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myfordboy's furnace

After making quite a few castings using just a large propane torch and a pile of fire bricks I thought it was time to make a proper furnace. The torch and fire bricks works ok, but is a pain to set up and wastes a lot of expensive gas.
I looked around for a suitable sized steel dustbin ( trash can)  but couldn't find one suitable at the time, so decided to roll my own.

This is how my furnace was made.

I bought a small sheet of 0.5mm steel from the local DIY store and some 25mm x 25mm steel box section. The sheet steel was cut to size and rolled to form the body and the box section added to form the legs. One of the legs is longer than the others and extends to the top of the furnace.
50mm x  6mm galv screws and nuts were used to join the ends of the sheet together, passing the screws through the long leg and into the steel casing. There were left full length on the inside as this will help hold the refactory in place.
 A hole was made for the tuyere and a disc of MDF cut to be a snug fit on the inside of the casing. Two further pieces of MDF were cut and holes made in them to suit the outside diameter of the casing. These 2 formers were placed as shown below to keep the casing in shape when the refactory is added. The disc has a sheet of plastic laid on top to prevent the refactory sticking to it.  
 


The disc in the photo is resting on top of some wooden packing equal to the height of the plastic paint can which will be used for the inside former, less the thickness of the disc. The 20mm dia white plastic tube you can see was to form a trough and escape hole for any metal spills but this has proved to be too small. 

Update 22/07/14
If I were to make another furnace I would not bother with the drain hole but add another inlet in the side for a blower. See the details of my blower at the bottom of the page. This has speeded up melt time as well as using less gas.
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The Refactory.
From a garden center I bought a 100Lt bag of  Perlite and from a stove center, two 12.5 Kg tubs of Fire Cement. After the job was finished I had half a bag of the perlite and about 1/4 tub of fire cement left.
The mix is 4 parts of Perlte to 1 part Fire Cement by volume. It is not that easy to mix so and I found the best way was to add a little water to the fire cement and mix in a bucket using your hands ( wear rubber gloves). Any water added has to be evaporated before the furnace can be used so as little as possible was used but enough to make the mix workable.



At the bottom, some galvanised steel wire was tied between the protruding screws inside the casing to help key the refactory to the furnace, like the reinforcing bars that are used that in concrete.

The mix was then added .........




.....and smoothed to a nice finish.


This now has to be left to dry. It could take a few days depending on the air temperature in your part of the world. When it was dry enough to handle it was turned over and the disc removed.

For the inside former I used 5Lt + 10% extra free, plastic paint can. A further piece of the metal sheet was bent and added to the outside to make a bracket which will later hold the burner. A tube of silicone was used as the former for the tuyere. The screws were again left long on the inside of the casing.





Another mix of refactory was then added around the former .This was then left to dry naturally for a few days until I felt the former could be removed. Once it was removed a 60 watt light bulb was suspended inside to speed up the drying process. Next I dried it further by putting it inside the kitchen oven. It just fitted. Since the furnace was made we have had a new oven and I don't think my wife would let me do this with the new one!
You can see in the photo below I also added a ring and rods to give extra support to the bottom.
 




The lid was made in the same way as described to the dimensions shown in the drawing.

The Burner
I already had a Sievert propane torch set which has an economy setting, the main flame can be shut off and a smaller flame kept going. I made a new necktube to fit it using a jet from one of the nozzles I had. It is not essential  to use a torch handle, a simple gas tap would do the job. I use an adjustable regulator set at 2 Bar (28psi) and this incorporates a hose protection valve which cuts off the gas if the hose should fail.



 A hose clip determines the length of tube that goes inside the furnace.





                                         Close up of the jet.





To hold the burner in place the bracket shown below was added, the holes are a loose fit on the burner tube. The burner tube is not sealed into the large hole in the furnace (this is called the Tuyere) This allows air to be admitted around the burner.


The furnace was heated up slowly several times to prevent cracks before being put into service.











The Kasenit Furnace
If you are following my metalcasting videos you may have spotted I am using a different furnace in  Part 29
This is a commercial furnace that was recently given to me. It was in a rusty condition but a clean up an a coat of heatproof black paint smartened it up. It was originally made for town gas but the previous owner had changed the jet and it now runs on propane. 
By coincidence the internal dimensions are identical to my home made one.
I was interested to see how it's performed compared. 
The main difference in the design is the vertical air inlet to the right of the burner, and the design of the burner itself which screws into the side. There is no hole in the bottom.







Performance

Well I have to report there is no noticeable difference in performance. I have not measured the gas consumption of the home built furnace but I have recorded it for this one.
I was surprised how little I used. I weighed the gas bottle before and after the melt and found 0.3 Kg had been used. From this I got 3.88 Kg of metal after the dross had been removed.  

The advantage of the Kasenit furnace is that the refectory will be good for melting brass and bronze if I ever need to. The homemade one with the perlite lining is not designed for the increased temperature though ideal for aluminium melting.

Update 16/07/14

For a year or so I have been using a clay/graphite crucible in place of the home made stainless steel ones. The reason for the change is the stainless steel storage containers don't seem so easy to get now and they are thinner. This meant I could only get about 3 melts from one before it sprung a leak.
As expected the time taken to melt the metal is now longer. With a stainless crucible the heat from the burner is transfered  easily through the metal but with the graphite one the whole furnace needs to brought up to temperature.
I have been using the burner supplied with the Kasenit furnace without any thought but one day I had my hot air gun handy during a melt and blew some air into the vertical slot next to the burner. It seemed to make the burn more fierce but it did not reduce the melt time.
Then I thought I would try my home made burner with the blower and it was a big improvement. 


The blower was taken from a hot air gun



Temporary set up to evaluate blower



Finished burner with blower



Flame pattern with new burner




 This is the Amal burner on the same pressure setting, 2 Bar


16/08/14
New burner design.
I have simplified the burner design to use plumbing fittings and no jet is now needed. Easily made in a hour or less. 





The video above shows the construction.
Here are the dimensions:
15mm copper tube 80mm long
20mm steel conduit 225mm long
Hole for the gas jet is 1mm dia.
I tried the burner with  the 20mm steel tube and also a 22mm stainless tube.
Both worked equally well, I used the 22mm one in the end as it fits the hole already in the furnace.



Oil fired Furnace
The Artful Bodger has a great design for a waste oil fired furnace which is easily and cheaply made. This furnace is capable of melting iron and if you have a supply of waste oil its free to run.
Full details are given in Colin's book.












190 comments:

  1. i am not sure about the construction of the burner tube. How is the part at the jet end of the tube made. also,is the fire cement in powder form or paste?
    THANKS, SKIP

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  2. The part at the jet end is made from steel using a lathe. Fire cement is ready mixed in paste form.

    ReplyDelete
  3. Hey There,
    I don't know what kind of stainless steel pots
    you've got over there, but I've tried everything
    between 1/4" walled SS pipe to malt mixing cups
    and melting scrap and alum. cans has ate out the
    wall on every one of them in the first two burns.

    ReplyDelete
  4. Hey Grandpa Bill, that sort of thing happens when you're got too much air entering your furnace. Ideally you just want only as much air as is necessary to support combustion, any extra just cools down the furnace and oxidizes whatever's inside. So, cover your drain hole and plug up any extra space around the outside of your burner tube and your crucibles will probably last a lot longer.

    ReplyDelete
  5. Hi,

    What are the units on the diagram? I'm guessing inches, but can you confirm?

    ReplyDelete
  6. Is there a reason that the hole on the lid is offset? How many melts do you get out of that propane tank?

    I love the videos and watched most of the metal casting ones yesterday. This is an area that I hope to get in to very soon.

    ReplyDelete
  7. MyfordBoy, I am also interested in what you are using for a crucible. I see in one of your YouTube videos you say it's a "steel kitchen container". I am presuming you mean the ones that come as a 4 or 5 part multi-size set with lids, for putting things like flour and sugar in? Is it stainless steel? I am also presuming you use stainless hardware, and the two "tabs" look to be flat iron bar. Thanks for all the information you've posted, and the thoroughness of your videos is appreciated.

    ReplyDelete
  8. @Grg I can position the lid so the hole is in different places to get the best burn.

    @Ian The crucibles are like you suggest. Two metal plates are added for handling.

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  9. sorry I do not understand a thing but the white tube and passing just to the lower floor?

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  10. The tube was to form a channel and hole in the bottom of the furnace to allow and spilt metal to escape. The hole proved too small but a suitable size is shown on the plan.

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  11. cement for fire must be at least 8 hours or quick drying?

    ReplyDelete
    Replies
    1. It takes much longer to dry out. Depending on where you live. I left it for a few days before adding the light bulb and oven treatment. Slowly is the way to go.

      Delete
    2. Hello. After you made the Foundry and the burner tube i noticed on the outside of the furnice you added a piece of bent metal (picture 6 of 15) where you put the caulk tube in. What i am asking is how did you get the burner tube that is 3/4 inch OD to fit Snugly in the larger tuyere hole which is 2.00 inches in diameter. I also noticed on the completed Furnace refering to picture 13 of 15 you have the Burner tube inserted and it looks to me you added something to make the 3/4 burner pipe fit snuggly. Can you please Help!

      Delete
    3. Also the part i am refering to is the one where the hose clamp stops(butts up against) the tube for desired insertion!

      Delete
  12. I have attached a link has a picture of a gun to see what the difference between your and one in pictures


    http://www.okaffarefatto.it/INSERZIONI2/022/INS00041/INS41_Files/DSCF1078.JPG

    ReplyDelete
  13. Thanks for all your posts, myfordboy! Really appreciated. I've sourced everything for the furnace. Start in on it tomorrow...

    ReplyDelete
    Replies
    1. All done.

      Almost ready for my first casting. I've made plenty of ingots (easily enough for a new center steady for my lathe). Haven't tested for inclusions & porosity in the ingots, yet.

      Finalising the fabrication on the wooden master mold.

      I used a 2" tuyere and a Bullfinch propane burner with a 1260 (2") flare and a #60 (1.0 mm) jet. My propane bottle is 47kg (2 bar). The bottom drain/air-intake wasn't sufficient for use with my burner (flame spluttering at higher throughput) so I opened it up to 2" and repaired the lining... Although, it still melted 15 liters, as was, of ally quite quickly (about 20 mins per melt). Left a redish residue on the inlet side of the trivet (red-oxide?).

      I used a home-made, 6mm wall, 3 liter steel crucible for the scrap melting and will move up to a stainless food container (as suggested) for the casting pours.

      Asda value cat litter was about 50/50 bentonite and gravel. Lot of hassle to separate. I'm going for the Catsan clumping formula if I have to do it again. B&Q playsand is lovely, fine and fluffy.

      Also using "cider vinegar", to eliminate castings from the melts, as the hydrogen reaction is better.

      Would like to fit a thermocouple to it.

      Thanks for time & effort. Much appreciated. I'm on my way...

      Delete
    2. Pleased to hear your build went well. I am not sure who you are, everyone is called "anonymous" so I don't know who I am speaking to.
      I have a thermocouple but found its not required, its best to pour as soon as its melted and you can see when that is.

      Delete
    3. I was thinking of using the thermocouple to aid in tuning the furnace and burner combo. See what temp it's capable of. I didn't want to deviate from your directions too much, unfortunately I had to accommodate the equipment I had on hand.

      I reasoned that I could also use the furnace as an oven for soaking larger parts re; annealing, hardening & tempering. Some experimentation with glass melting for sculpture would be kinda cool, too (laying burner on its side).

      For the fingers of the center steady I'd like to cast from brass (~900*c). Are there any similar products for use as a brass flux & degasser, like there are with "lo-salt" & "soda crystals" for aluminium?

      The lathe is a 1939 Hardinge Cataract. Beautiful machine. Parts & accessories are a little hard to come by. :)

      I'd like a forge. My one bug-bear is sorting a decent steel anvil. Good one's never come up for sale where I live. I would like to cast & harden my own. Any advice or suggestions would be most appreciated...

      Thanks for sharing your knowledge & experience, myfordboy!

      Apolls for name, was rude of me,

      knoba

      Delete
    4. Knoba, I have only just tried brass myself.
      http://www.youtube.com/watch?v=-XJNeQ_U-RQ
      Borax is the what to use for flux.

      Delete
    5. Good video & nice job!

      I did another round of aluminium ingots today.

      The enlarged 2" drain/air-inlet worked very well. Produced a melt in approx 10 mins with the same gas feed rate (interior of furnace was much hotter, more efficient). The enlarged inlet opening also allows a much higher gas flow rate, if desired. I had already fitted a sliding waste gate over the drain hole, so can adjust air input from drain, (rich/neutral/lean).

      Open air ingots (cake tin mold) were coming out with heavily granulated breakup on underside, but ironically, with a better topside surface finish... :) Too hot, too quick, bad metal, etc...

      Steel crucible holed. Inspection revealed a 1" wide x 4" long band area had completely eroded away, on the circumference, near the base. The rest of the crucible is fine. Suspect flame super-heating this area accelerating deterioration and allowing iron absorption into the melt.

      Most fun I've had in a long while... :)

      knoba

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    6. Patched up the steel crucible & added some 3" stand-offs to raise the trivet up so the crucible isn't heated, directly, by the flame. All good, now.

      Made a stainless steel crucible for brass & did my first melt. Didn't have any borax(flux) so went without. Took 3x as long to get to melting point. 11kg melt. Open sand mold. Made a 4" o/d x 1" round, machined back & everything's sweet (no inclusions).

      The colours & luminescence of the molten brass when I skimmed back that dross was jaw dropingly beautiful...

      Next move is graphite crucibles.

      Thanks, myfordboy. It was your videos that got me into casting.

      knoba

      Delete
  14. there was a question above about how many "melts" you can get out of a standard propane bottle, im curious too!

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  15. I did wiegh the gas bottle once and compared it with the quatity of metal melted but I can't remember the results exactly, I think it was 5Kg metal for 1Kg gas. Next time I fire up I'll record the result.

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    Replies
    1. sweet thank you, iv been looking at this for weeks now and i want to get into it. here was my first attempt when i got too bored the day i decided to try casting, feel free to point and laugh :)
      i had an old coffee can with empty soda cans in it over w wood fire (pine, birch, pecan, sweet gum) the cans would get soft but not melt, so to make them melt i used spray paint (about 2/3 the bottle) to heat it up more. my make shift crucible supported by hand ( 3 pairs of gloves soaked in water) poured out 2 0z ish of liquid metal into a shot glass. after a few days my fingers were well enough to play on my computer i find your videos and this blog (should have done that first) now armed with information iv played with it some more (metal tongs after that first time) and more and more. its destructive creation and i cant get enough of it!
      ``Derek

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    2. I did a lot of casting before I built my furnace using a large (85kw output) propane torch and stainless stew pot. It is quite possible to melt the just same as with a proper furnace but the gas consumption is extreenly high and its not as safe or convenient to use. You could try a charcoal furnace with a simple blower. There are designs on the web for these. Please work safely, no more burn fingers.

      Delete
  16. Thank you for your contribution...I want to use your plans to build this. Very well explained, but what do you mean when you use the word "former"? Are you using it to differentiate between two points, former and latter, or are you using it as a verb, as in to form something?

    And are you using two "formers" the outside being the sheet metal casing, and the inside being the paint can? And the two formers are basically used to shape the refactory (fire cement and perlite)?

    I just want to clarify because I am pretty new to this whole thing. I saw a foundry online for sale, the guy wanted like six hundred for it and that is crazy! So I want to build my own instead.

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  17. From the Oxford dictionary of English
    "A person or thing that forms something: a tool, mould or other device used to form articles or shape materials."
    The paint can is the former, used to shape the refactory. The outside sheet metal is the outside former but is left in place.

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  18. your videos are quite explaining the procces but can stailess steel bucket hold molten iron and

    ReplyDelete
    Replies
    1. No, it's only suitable for aluminium. You would need a regular foundry crucible.

      Delete
  19. Two questions (and thanks for this information):

    1. I looked at the gas jet drawings and googled "Sievert propane torch" and it appears to be a "repurposed" blow torch with just the stainless steel pipe added. First, is this an accurate interpretation, and if so, what is the purpose of adding the long pipe? Why would you not put the business end of the torch as as close to the interior of the furnace as possible?

    2. Do you think using an aquarium pump or blow dryer or some such (low pressure) forced air source would increase the heat output or is the design of the torch such that it sucks in all the air it can use anyway?

    I have been playing with smelting lead using an outdoor cooking grill and a MAP gas torch, and am really interested now in building this and expanding my "foundry capabilities". Thanks for the information! It is greatly appreciated!

    And TIA for the two questions (actually, I guess at least three questions:)...

    Allen

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  20. After watching the video, I see you *replaced* the burner on the torch, so question #1 becomes "Why?". Why not just use the burner that came on the torch and make the furnace bracket so that it could hold it in place?

    Thanks again!

    Allen

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    Replies
    1. Hi Allen
      You need to get the tip of the burner into the furnace. If you just used the supplied burner it would be too far inside and would not be able to take in the air. I only used the torch becace i have it. A simple gas tap would serve but the torch has an economy setting, there are 2 control knobs, so i can turn of the full gas supply when adding more metal and still keep a small flame going.
      Some burner designs use forced air as you suggest but its not necessay for melting aluminium. My design is economical with the gas.

      Delete
  21. For drying out in the oven.. It's best to ask for forgiveness than permission...

    Joe

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  22. myfordboy,
    Over here we use the "Webster's Dictionary" and very rarely at that. I was wondering if you could omit the oven process. My wife would kill me if I tried that. Also, what is the purpose of the burner hole being offset?
    One last thing,could you elaborate on the pre-heat cycles you used to cure your furnace, duration, temp, cycles.
    Thanks,
    John

    ReplyDelete
    Replies
    1. The burner hole is offset and tangent to the furnace so that the flame swirls around the crucible.
      The refactory is dried slowly to prevent cracking, I can't recall the exact times but a 100w lamp was hung inside for a couple of days initially. If your wife doesn't understand you (!) and won't allow use of the oven you would have to apply heat slowly and gradually build up to a full heat.

      Delete
    2. Hi myfordboy,

      first of all thanks for sharing your knowledge and experiences!
      I felt inspired to give this adventure a try too and am currently
      at the shopping stage.
      I plan on using an old cut off porpane tank as a solid chassis
      (approx 30cm=12" outside diameter) which should come down to pretty much the same dimensions you show in your drawing.
      Doing the math for the refractory ingredients and supplies I was only wondering about the amount of perlite:
      The outer dimensions of 11.25" diameter and 14.5" height takes me to about 1441 cubic inches (not considering the void space of chamber and hole in the lid) which should come down to about just a little less than 24 liters.
      You mentioned that you had about half of a 100lt bag of perlite left after the job was done so I was wondering where all that perlite went.
      Are you sure that was a 100lt bag or could that have been a 50 lt bag?

      Anyway - great projects, brilliant documentation and fantastic results!

      ...can't wait to chop up an ols cylinder head and get going myself...

      Looking forward to read about any new projects on your side - pleas keep it up this way!

      Beast regards

      Piter

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    3. Piter. I have checked and it was 100lt.There may be a bit more than half left but it defiantly used more than 24lt. If there is a 50lt bag that should do it.

      Delete
  23. Hi myfordboy,

    thanks for the soon reply!
    Maybe I just got my maths all mixed up - the perlite
    sure doesn't take the project to the edge of bankrupcy anyway
    and the remaining material can always hit the flowerpots...
    I just played around with the figures for a while when I was
    trying to make up my mind about scaling up the furnace a little
    bit. I think I'm going to leave it with the propane bottle and
    the same size as yours for starters though.

    By teh way - does anyone have any experience with running a
    'Ron Reil'-type burner in this size of furnace and any hints for suitable component sizes (fittings and nipple diameters)?

    Thanks and best regards again

    Piter

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  24. Thanks for all of your excellent video's! I have been watching, and re-watching them for months and can't wait to get my own furnace going. Your mould making skills are also amazing!

    -Jerold

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  25. Thanks for all the work you are sharing.

    are you going to use the perlite cement mix for the brass work? or will you use something else. i have seen others say that the perlite will melt at the temps needed for brass.

    dave

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  26. Dave, No I won't use the Perlite mix for brass. As you say I don't belive the perlite or the fire cement would last very long at the higher temperature. The mix has proved exeptional though for aluminium, I have done hundreds of melts with it and it still looks almost as new.
    I have recently been given a Kasenit furnace and have just refurbished it but haven't actually melted in it yet. This will be my brass furnace. I hope to try it at the weekend.

    ReplyDelete
  27. thanks mr myfordboy for passing on your knowledge, after finally building a furnace i managed to melt enough alum to get a couple of kilo ingots, it did take a good half hour per melt but i reckon i can fine tune it as time goes by, it'll be trial and error with gas and air mix, ventilation on the furnace and such like. this has taken me a good 4 months to get it all sorted as money is short and i'm also trying to convert my wood lathe to a metal lathe, i'm getting there so all is cool. so thanks again and keep up the superb work on the blog. ttfn from tetley

    ReplyDelete
  28. Been watching lots of your video's and they are great.

    I want to build my own furnace for melting aluminium.

    Plan so far looks like using a 13kg sized gas bottle for the outer shell.

    Perlite and fireclay for the inner.

    I was wondering. Would an inner stainless steel or similar liner work?
    With the perlite between to insulate it?

    Ive not seen anyone do this. Would it take too much time to heat up? Must be a reason why its not done.

    Thanks. DRJ.

    ReplyDelete
    Replies
    1. Hi DJR
      The stainless steel would get holes in it from the burner.My stainless crucibles eventualy get pin holes and have to be replaced.
      Some builders use a seperate hot face of half an inch of a refactory material.

      Delete
  29. So do the perlite mix as i planned then add 1/2" of pure fireclay for the inner wall?

    Or do the perlite mix, Add the metal ring inside then 1/2" of fireclay on that? Or will that just crumble and fall off?

    Just seen 25kg of rammable refractory on ebay just over £40 ready to use 1600C.

    Be a bit of a pain if i decide i need to alter the size for any reason and have to break it out though.

    Been scouring the kitchen isles at the supermarket looking for a decent thick walled stainless container.

    I dont want to spend too much, Just in case its a one off.

    Thanks for the help.

    DRJ

    ReplyDelete
    Replies
    1. DRJ
      Forget the metal ring. My furnace just as the perlite and fire cement mix and just a thin coat of fire cement on the inside just to smooth off the finish a bit. No problem for melting aluminium, has withstood hundreds of melts.

      Delete
  30. Me again, What a minefield. I notice you use cement where others seem to say fireclay.

    Fireclay seems to be cheaper. Is this an option? Or is there a reason you used cement?

    Thanks for your time.

    DRJ.

    ReplyDelete
  31. DRJ
    It's not cement like you would use to make concrete but fire cement, used to seal and repair flues and fireplaces.

    ReplyDelete
  32. How does it differ to fireclay though? When they list fireclay they seem to suggest its for building furnaces and using as a refractory.

    Even making crucibles, With the right ingredients.

    Thanks.

    DRJ

    ReplyDelete
  33. Hi Myfordboy
    Fantastic source of information, I am at present construction a furnace to your design but would appreciate advice regarding the ramming of the fire clay and perlite ,Should the refectory be rammed with a large amount of force making the mix dense or just applied so that it fills all the gaps? I have the opportunity to dome the inside of the furnace lid , do you think this would help reflect the heat source , or possibly be detrimental to the heating process .

    Thanks in advance

    Keith

    ReplyDelete
  34. Keith,
    To get it to mix I added a little water to the firecement so it was wet enough to coat the perlite, so it did not need ramming. It was like laying concrete. Some builders use poystyrene beads which burn away after fireing.I don't think there is any advantage in domeing the lid. The refactory is more of an insulator than reflective.
    I have a layer of ceramic blanket on my base now and that reflects a lot of heat.

    ReplyDelete
  35. Will fireplace refractory cement work?will a 500,000 btu torch melt copper?Will 100% natural clay kitty litter work for the greensand?

    ReplyDelete
    Replies
    1. Kitty litter is fine but the fireplace cement will not be suitable for the temperature required for copper. The burner though should have plenty of heat.

      Delete
  36. Thanks for your quick response on kitty litter and 500,000 Btu torch do you have any suggestions on what I could use to build a foundry just like yours but hold up to copper melting and what kind of crucible to build.by the way the torch is just a fleet farm grass burner torch that says on the package it will burn that hot

    ReplyDelete
  37. You need a commercial refactory to line the furnace but I understand that copper is very difficult to cast. Brass or bronze is easier.

    ReplyDelete
  38. Could you please explain why copper is so hard to cast and what I will need to make a successful cast all info given is appreciated highly thanks

    ReplyDelete
    Replies
    1. I have only cast copper and brass so cannot advise but here is something you could read.
      http://www.alloyavenue.com/vb/showthread.php?7433-Anyone-cast-pure-copper-before

      Delete
  39. Could you please give me names of refractory cements to look for and possibly store that sell it in the USA or a good brand to look for and will your stainless crucible hold up to copper melting thanks I appreciate all the help you've given me so far just need these questions answered to starts casting so please help thanks

    ReplyDelete
    Replies
    1. I am in the UK so can't realy advise on a US supplier but I belive refactory may be available from Ebay sellers. A graphite crucible would be best for copper. A stainless one would not last very long.

      Delete
  40. Few delays. But im almost ready. I think?

    100L Perlite. 25kg of KOS Fire Cement. 15kg Gas Bottle (Empty).


    How do you measure the fire cement and perlite? I imagine this will be hard work to mix properly and will need to do it in small chunks.

    Any idea how i can build it so that i can alter the internal dimension
    for different sizes of crucible?

    Or is that going to be difficult? Will a 2" thick brick of these materials be too weak?

    Many Thanks for your help.

    DRJ

    ReplyDelete
  41. @DJR
    I used a small plastic tub and filled it with perlite. Tip 4 measures into a bucket. Add 1 measure firecement. Add a little water and mix as mentioned in the instructions above.
    I can't see how you can make an adjustable size furnace. 2" refactory is fine. There should be about an inch around the crucible wall minimum.

    ReplyDelete
  42. Not too sure myself about the adjustable part.

    Just an idea. Its 12" across and 15" deep without the lid.

    My trial stainless crucible is just under 4"

    So not a huge way off the size of yours. I was thinking if i made
    a 2" layer on the wall of the cylinder and then 2" bricks that can
    be inserted or removed.

    Maybe thats too much for a 1st attempt.

    Just noticed your top exit hole is 4". I didnt cut mine that big.
    Looks like i may need to alter that.

    How much of a difference does the bottom vent hole make to the burn?
    Too big/too small?

    Is it worth making a small vent door for it? Spring operated so anything falling on it will open it or maybe a wire operated one?

    I had a vision of measuring the clay and not being able to get it all out of the tub making a mess and not the right ratio.

    So eager to start mixing and filling it up. But resisting that urge until all the holes are made. And trial fitted it all.

    Thanks for your time.

    DRJ

    ReplyDelete
  43. @DJR
    I wouldn't wory about the adjustabe part. I have used a range of stainless crucibles without problems. The hole at the bottom was just to let metal escape is your crucible gets a leak. I made mine too small and it filled up with metal and is now blocked, makes no difference to the operation. The kasenit furnace mentioned in the description has no hole. I put a lining of ceramic insulation on the bottom now, if I get a spill I can tip up the furnace and let it out whilst still hot, Take care though!
    I expect you were aware of the dangers of cuttin up a gas bottle but mention it so others can take note.

    ReplyDelete
  44. Yeah the bottle had been standing for 24 hours with a peg holding the valve open. Then i removed the valve and its been filled with water for a week.

    Emptied it and refilled twice more, Then left upside down for 48 hours.

    Only then did i take the grinder to it. Even thought its cut open and outside, I still get the odd whiff of gas. But i read the smell stains the metal and lasts for ages.

    Finding containers the right size is a pain.

    Possible i may made them out of cardboard and fill with sand to help it stay in shape?

    Is a 3" top hole too small?

    Thanks. DRJ


    ReplyDelete
    Replies
    1. @DJR
      I would think the cardbord would work. How about wrapping in clingfilm for a smooth surface finish?
      My hole is 4",I would enlarge yours if possible.

      Delete
  45. Hey its me again I found some refractory its 60 us dollars for 50 lbs and its rated for well over 2000 degrees ferenhite so I would like to know how much cement did it take to build you foundry and I would also like to know how tall your foundry is not counting the legs and how wide and thickness of the walls in inchs fyi the refractory is powder form had to be mixed can this withstand copper thanks for all your help

    ReplyDelete
  46. @apprentice
    The dimentions are shown above in the description of the construction and also the quantity of perlite and fire cement I used.
    I would ask the refactory supplier what volume the 50lb makes because it will be different from what I used. Copper melts at around 2000F so it would be at the limit of temperatue required.

    ReplyDelete
  47. Amazing your great

    ReplyDelete
  48. Does everey cast you make has to have a core

    ReplyDelete
    Replies
    1. You usualy only need a core to make a hollow casing or large hole.

      Delete
  49. Thanks . From crazy guy

    ReplyDelete
  50. How many minutes does it take to melt 3 kg metal

    ReplyDelete
  51. So your drawing says your foundry is only 12 inchs tall it looks so much bigger am I correct or are you using inchs

    ReplyDelete
  52. Dimentions shown on the drawing are correct. Height is 12"

    ReplyDelete
  53. I can't seem to figure out your wall thickness please help? Ok got some info on the refractory its a 40 lb bag it says 10 lb will cover 1 inch thick 1 sqft. can u tell me how many bags I will need? thanks again

    ReplyDelete
  54. This comment has been removed by the author.

    ReplyDelete
  55. I reccon you need 2 bags.
    volume is 0.64 cu ft.
    1 bag does 4"x12"x12" =0.33 cu ft.

    ReplyDelete
  56. This comment has been removed by the author.

    ReplyDelete
  57. I just went to Wal Mart and saw, in the gardening section, a bag of Perlite. It was an opaque bag, but it felt like pellets, I'm assuming it's the little white "beads" used to prevent soil from compacting. Apart from the fact that this stuff was "enhanced" with Miracle Grow, is this the stuff I'm looking for? Would using this work, or should I look for stuff that's not "enhanced". I'm also having a really REALLY hard time sourcing sand for making the greensand. Wal Mart only has paver sand, which looks far too course and pebbly. I'd like to avoid buying online since sand is heavy, which means shipping would be costly.

    ReplyDelete
    Replies
    1. You don't need miracle grow in your perlite!

      Delete
  58. What are the dimension of the former paint can +10%? How many inchs thick are the walls on foundry please answer?

    ReplyDelete
    Replies
    1. 9.5" high 7" dia. as shown on the drawing.

      Delete
  59. Hi Myfordboy. Great Job. Any cuestions please.

    In the Metal casting at Home Part 9 The Furnace you shown a steel crucible.

    1.- The material crucible is stainless steel ó carbon steel specification?

    2.- Please, what´s the thickness crucible.


    Thanks.

    ReplyDelete
    Replies
    1. @ Boby
      I am using stainless steel storage jars as crucibles. They are thin and last about 8 -10 melts but are cheap and easily available.

      Delete
  60. I managed to get some perlite sans the miracle grow from a garden center. I also picked up 4 40 lb bags of play sand (3 of which are drying on a tarp on the patio right now). I've been posting on alloyavenue, where I'm told you're a respected member. I'm trying to get some detailed information about the exact recipe for making a furnace refractory, but no one there seems to want to provide it, they all just recommend that I go out of my way to get a commercial refractory. I've got the perlite and the sand, and there's a store semi-locally that sells various fire clays and something called "kiln cement". Can you give me any tips on what else I might need to get this off the ground. I have a 12" diameter steel cylinder that I'm going to cut a little shorter, to use as the outer shell, I plan on using 2" of refractory, leaving an 8" hole in the middle (unless you recommend otherwise), and I'll build a propane burner. The issue I have with buying a commercial product is both that I like doing things myself, so I learn, and that I'm moving sometime in the next year and probably won't be able to take the furnace with me, so I'll have to build a new one. I don't know if I'll be able to get a commercial refractory where I'm going, but I'm sure I can find the base materials.

    ReplyDelete
    Replies
    1. Halo,
      I belive the US equivelent of the fire cement I used is available in a hardware or fireplace stores, Black Worcester Brush brand, Meeco or Rutland high temp furmace cement. I used a mix of 4 parts perlite to 1 part cement by volume.
      Your furnace dimentions are fine.

      Delete
  61. Thank you for the reply. I've been asking around for fire cement and very few people have heard of it, maybe I'll start asking for furnace cement, or by brand name.

    ReplyDelete
  62. Done the bottom section, I may have added too much water, Got a few hairline cracks. Plan to cover those when adding a skim over the surface.

    Hopefully its not an issue. Thinking now i wish the lid was a bit bigger.

    Oh well. Have to think of a good way to make sure the mix stays put.

    Thinking about that fire proof blanket stuff (name?) 5mm as a liner maybe a good option to help protect the surface?

    Many Thanks for the advice.

    DRJ.

    ReplyDelete
    Replies
    1. @DJR
      The ceramic blanket is a great heat reflecting surface but will break up in time with the flame directed on it

      Delete
  63. Good job indeed. A small but well integrated furnace. It's really a fabulous task to see that it is performing well but have you checked out the safety points. Is it really safe at all?

    ReplyDelete
  64. hi myfordboy
    i have watched all the videos and red most of the faq's and was wondering if you take a propane cylinder cut of the top then cast 3 to 4 inches of the perlite mix in the bottom then carry on with the rest of the instuctions would that be ok my point being does it have to made from a tube of steel then cast a plug of perlite to close of the bottom or can you use a pre pluged tube
    kindest regards karl

    ReplyDelete
  65. Hi Karl
    Using a gas cylinder is quite a popular way of constructing a furnace.
    Be aware though of the danger in cutting it up. I belive the procedure is to remove the brass outlet and fill the cylinder with water and leave it for a long period to expel any remaining gas.

    ReplyDelete
  66. ok thats great any idea what size cylinder to use im thinking the 19kg would be about right size. i have a two part piece that i want to cast its fairly heavey about 4.5 kgs of metal with about a 2 thid split so 1 is about 1.5 the other about 3kgs but i dont see any way of casting it can i send you a photo some how to give you an idea what im up against also would you be interested in casting them for me maybe or some sort of a deal where are you in the uk
    kind regards karl

    ReplyDelete
  67. Karl,A 13 kg bottle would make a furnace the size of mine and would melt about 5Kg in the available space. You may send me a photo of your project and I will see if I can help.

    ReplyDelete
  68. ok thank you i have a 19 a 13 and a 7,5 so thats ok how can i send you a photo by email also where are you uk just roughly
    kind regards karl

    ReplyDelete
  69. GREETINGS KNOW, I agoes from Indonesia I have seen your prowess in metal printing, and I am very impressed with your expertise, if I may know what the green sand material could create? Thank you in advance.

    ReplyDelete
  70. Hi aremabkfarm
    Something may have got lost in translation but I think you are asking what items can be cast. I cast parts for model engines but any object could be cast e.g sculptures, see my metalcasting video series for ideas.

    ReplyDelete
  71. hi myford im a bit stuck can you help please
    karl

    ReplyDelete
    Replies
    1. What,s the problem Karl? I had your email but no photo.

      Delete
  72. hey myfordboy
    i was wondering if the refactory cement mix that you use could also be user to make a crucible aswell and do you think it would last??

    thanks
    Lindsay

    ReplyDelete
    Replies
    1. Hi Linsay,
      I dont think a crucible like this would be strong enough to handle when the the weight of metal is included. More importanly the refactory is an insulator so the heat would not be transfered to the metal.

      Delete
  73. hi myford thanks for that the email was a tester to see if i got it correct i will take some pics and send them via email
    kind regards karl

    ReplyDelete
  74. My furnace is coming along, Drying it very slowly in this miserable damp climate.

    Just noticed its getting lighter. Even the lid weighed a lot, When i started.

    If it helps the above questions, I used a 13kg gas bottle. As mentioned make sure its as empty as you can. I used a regulator to vent it. Then left a bar pressed onto the valve to keep it open for 2 days.
    Then removed the valve. Filled with water. Left for 24 hours+ then repeated. Left it upside down overnight to drain fully.

    Then cut the lid off. I only cut the lid right where the radius starts, Wish i had made that a bit bigger now but never mind.

    Internal dimensions are 7" across and 11.5" tall. This is with approx 2 3/4 inches of refractory.

    Glad i listened to the advice here, Restricting the top vent has a serious effect on the flame. Glad i made it bigger as suggested earlier.
    Thanks.

    Slightly too big and you can cover with a firebrick or slate etc. Too small and it wont fire properly.

    To do my 1st tests i have some stainless cups from asda 3 for £5. Do i sit it on the base or make a stand?

    Thanks.

    DRJ.

    ReplyDelete
  75. Hi DJR
    Sounds like it's comming on fine. Did you use the light bulb inside to assist the drying?
    You can see on the video I have the crucible sitting on a little trivet. The bottom of the crucible is level with the centre of the burner.

    ReplyDelete
  76. Yeah i did use a bulb also. Not sure how much it helped to dry it.
    But i thought its a good way to prevent thermal shock anyway.

    Got the flame going now as i type this. With the cold UK mornings
    is it a good idea to put it on a low flame to warm it 1st?
    Or have the bulb on overnight.

    Thanks for the tips.

    Bottom level with the centre of the burner. Excellent.
    You saved me when you said 4" for the top vent. Mine was smaller.
    Glad i made it bigger.

    Thanks.

    DRJ

    ReplyDelete
  77. What did you use for the trivet? Do i need stainless or will
    any steel work? Anything to avoid?

    I have visions of it welding itself to the crucible.

    Are your jars from ASDA in a pack of 3 for £5?

    Thanks again.

    ReplyDelete
    Replies
    1. I would dry it as slowly as you can to avoid cracks. You can fill any cracks though with the fire cement.
      There is no Asda where I live but I recently got some suitable containers at a local discount store for £3 each. They are 6" tall 5" dia. This size holds 5Kg of metal.
      The trivet is steel screwed together. I don't have a welder but that would work fine. Eventualy it may need replacing.

      Delete
  78. Seems to be drying well.

    I placed a tub in to see how the flame swirled and accidently blocked the bottom drain hole, No trivet. On a fairly low yellow flame this had the effect of coating everything in soot.

    The torch im using to dry it is like a weed burner approx 2" diameter with 6 holes these maybe a bit restrictive or may work better with the gas turned up. Trial and error i guess. May rig up a fan to help just in case.

    Trying to find tubs with a decent thickness is not easy.

    I now know the drainhole helps to draw air upwards though.

    Got some long 1" thick bolts from a towbar to make a trivet from.

    So fingers crossed.

    Thanks again.

    DRJ

    ReplyDelete
  79. Think im almost ready for my 1st melt...

    Need to play with the flame and nozzles. Good point above about the flame hitting the crucible directly. Creating a hotspot and burning through?
    May start with it just above the inlet hole and lower it after to see how it compares.

    When melting smaller quantities is a wide low container best or a taller one?

    Any tips on adjusting the flame?

    Thanks for all the info.

    DRJ.

    ReplyDelete
  80. I am a happy boy.

    I sort of melted some aluminium :)

    Just tinkering using the rest of my butane, Not quite happy with the swirl, Maybe its too cold for the butane.

    Dont want to waste my propane doing the testing though.

    Using the stainless container i managed to partially melt an old computer heatisnk.
    Had to shut it down because dinner was ready. :)

    I left it to cool in the container. Removed it the next day, Which i was not sure it would. Some dust in the base? Any idea what that is?

    Thanks for all the tips and advice.

    DRJ.

    ReplyDelete
  81. I had a play again. Melted well and i added a bit more aluminium. Was surpised to find my small container 3/4 full.

    Though what can i do with that. Spotted a bag of builders sand in the garden, Open to the elements and rather damp.

    Got a car shaped moneybox and push in into the sand, Scooped some upto the sides and pulled it back out. Left it all open because it was too wet.

    With a VERY long handle i poured the aluminium into the sand it sizzled a bit and i guess from the pockets in the metal after steam did try to escape. 1.5kg in weight. More than i expected from a small container.

    I have an A6 crucible now. And think i have found a 14cm x 17.5cm stainless tub. 5 1/2 inch x a smidge under 7 inch.

    Next step some proper greensand.

    Got me wondering now. When you use cores how do you keep them in position to get a contant wall thickness without having holes in the metal?

    Say casting a large model car 6" long. Without having holes on the exterior and without having it solid metal?

    Might have to think about that. Put some pictures up.

    Need to sort a saw out now to cut the metal up to the right sizes.

    Watched your video on what to use and not use. Why not extruded aluminium and bars? I thought this would be ideal material.

    I have seen video's on melting cans and after a hundred or so they have a tiny amount of metal, Most of it burning away as they put it in.


    Thanks
    DRJ.

    As Rolf Harris used to say... " Can you tell what it is yet... "

    http://i278.photobucket.com/albums/kk109/Grampian91/minimelt1.jpg

    ReplyDelete
  82. carbon monoxide is caused by incomplete combustion or improper exhaust' Unless he closed an exhaust damper (which most systems don't have), or monkeyed with the gas regulator (hard to do) Industrial Heaters

    ReplyDelete
  83. DRJ,
    You cannot make a hollow casting without at least one hole. The core needs support and you have to be able to remove it afterwards.
    Extrusions and bar can be melted of course but the properties of that grade of aluminium will be different from a casting, so for the best results stick to metal that has been cast before.

    ReplyDelete
  84. So just making a non important part like my model car and it will be OK. But anything that needs to be a decent quality/strength then avoid.

    I know when i 1st started looking lots seemed to melt cans the 1st time. One guy pulled out 6 large chunks of waste. I did wonder if he had any metal left over.

    Made this melt from computer parts. Got some carparts hiding somewhere, Turbo castings and waterpumps etc.



    Need to sort out a saw. Got some mitre saws to try and add a motor to.

    Try a fan and see if it gets any hotter with some blown air.

    Get a thermocouple maybe. Do you use one? Will they connect to any test meter? What setting do they need to get the correct temperature readout?

    Thanks for the time.

    DRJ.

    ReplyDelete
    Replies
    1. I have a K type thermocouple that plugs into a mulimeter but I don't ever use it. I pour as soon as the metal is all melted. It's not good to overheat the metal.

      Delete
  85. The advanced devices like Temperature Recorders are used in measuring the exact heat generated.

    ReplyDelete
  86. You have a lot to answer for Sir!

    I has trudging along happily with my Super 7 and messing about with OT when I happened across your posts on YouTube - and became addicted.

    That may seem innocuous enough, until you realise that I am Irish - with a gas tank and a furnace :-)

    The most suitable subject I could find was an empty gas cylinder, which I filled with water, emptied after a few days, then repeated the process before decapitating it with the angle grinder. Worked out fine so far. All holes cut out as per your plan and refactory in. I used a bag of "Ciment Fondue" with small pumice pellets (acquired from a friend).

    The only thing I could find to use as a former was a full tin of paint. Thinking "what could possibly go wrong" (and being Irish) I forged ahead - forgetting to wrap it in foil or similar.

    I will leave to your imagination the extraction process when I found it firmly cemented in place. Suffice it to say Sheila has now got reservations about using her ladle in the kitchen.

    Now waiting until the whole thing dries fully before I embark, teeth clenched, on the next stage.

    Thanks :-)
    Ruaidhrí
    Dublin

    ReplyDelete
  87. Thanks Delores Faulk. Nice bit of SPAM there. But i am not in INDIA.

    Whats the point of having a website if you dont advertise the prices? Waste of space.

    See if you had prices on the site your SPAM may have actually got a sale. Go and tell your web team to put prices on.

    India 0 : China 1. Thermometer / Controller / Thermocouples on their way from China. They got the sale because i could see how much the items were and had good descriptions with dimensions/options etc for the probes.

    DRJ.

    ReplyDelete
  88. FWIW - now have handles welded on, top and bottom refactories dried out and greensand -ish :-) ready. Just need to find something suitable for a crucible and I'll be having a bash.

    Again, thank you for a super collection of videos. I would never have dared embark on this unless I had seen them.

    Regards,
    Ruaidhrí
    Dublin

    ReplyDelete
    Replies
    1. Ruaidhri, Happy to be of some assistance.

      Delete
  89. Hi myfordboy,

    Thank you very much for so nice sharing with careful presenting your works and tutorials.

    Because I need to build DIY metal lathe similar like Gingery's but larger, with some combination of EG (Epoxy Granite) and other interesting techniques, I am building DIY foundry. It should be simple, classic, but solid machine for easy improving and upgrading to be like universal machine ...

    For some time I wandered with material for furnace because here in my country recommend mostly thermo concrete - I suppose it is ready mixture. But recently still I found looking same materials like yours: "Gorkal 40" (25kg - but dry cement), and Perlite (100Lt-10kg). Now I would build very similar maybe something larger furnace like your, for crucible capacity about 5-6kg aluminum, but with burning on charcoal (because it should be larger I suppose).

    1. Please, do you can recommend to me something about such my furnace, like maybe about internal diameter and height because there should be some enough space between crucible and furnace walls for charcoal ..., to consider these materials i found, or anything else?

    2. I found here also to buy foundry quartz sand and bentonite clay for molds. Because in yours foundry videos I found you recommended fine foundry sand for fine castings surfaces, please tell me which granulate of this sand I should to buy to do that (here is available 0,3mm, 0,8mm and larger) and how to apply that if there is something specific (?).

    Best regards, :-)

    Peter

    ReplyDelete
  90. Hi Peter,
    I have never made a charcoal furnace so I don't know what to recommend for the size. Maybe a Google search will show a suitable design.
    I would get the finest sand that you can mould. I don't know what grade mine is but it is very fine.
    Sorry if this isn't much help.

    ReplyDelete
  91. No problem, thanks! Best regards,

    Peter

    ReplyDelete
  92. Please, how many times about you can use your stainless steel crucibles?

    Regards,

    Peter

    ReplyDelete
    Replies
    1. They vary, sometimes only a couple of melts but usually about 6 to 8.

      Delete
  93. Hi myfordboy,

    Today i got materials for furnace and molds I mentioned. I firstly got idea to use charcoal for burning because it was appeared like very simple way (more DIY what I like), but because it is not so available in urban place like mine I decided still to use gas and build same furnace like your. Also I found many information on the net that burning charcoal release a lot of dangerous carbon monoxide, but I found similar for other kind of fuels like gas also ... Second I have a lot of cases from disassembled HDDs I read they are made from aluminum, but also from - zamak which can release also dangerous fumes when melt it. If you have some knowledge and experiences about how to avoid dangerous fumes in home foundry, please tell me how to do that.

    Best regards,

    Peter

    ReplyDelete
  94. I don't see any danger from fumes as long as the melting is done outside.
    Can't say I have ever noticed any when I melt other than smoke sometimes is the metal used is a bit oily.

    ReplyDelete
  95. bigjohnvette3 March 2013 03:04

    Myfordboy your site is awesome I have a couple of questions. 1) the salt you use is regular table salt? 2) washing soda is that the same as baking soda ? THANKS FOR ALL THE POSTS John

    ReplyDelete
  96. Regular salt is Ok but I think LoSalt or Litesalt gives better results.
    Washing soda is sodium carbonate,not the same as baking soda which is sodium bicarbonate.

    ReplyDelete
  97. Hello my ford boy,
    I made a furnace similar to what you showed. I couldn`t find fire cement so I used perilite and mortar. I used a weed burning torch. It goes directly into the furnace. The crucible gets red hot and a lot of soot is being produced but, it doesn`t get hot enough to melt aluminum. Any suggestions ?

    ReplyDelete
    Replies
    1. A sooty and yellow flame means not enough air. If your burner goes into the furnace it cannot get take air from outside the furnace.
      If you look at my burner design and those by others you will see the air is taken from well outside the furnace.

      Delete
  98. I live in Los Angeles. KOS fire cement is not available here. Any suggestions as to a substitute? I've done quite a bit of looking and am coming up empty!

    ReplyDelete
    Replies
    1. I believe the product you need in the US is Worcester Brush High Temp Furnace Cement.

      Delete
    2. Thank you. I guess since the burner has opening to the rear of it that it was pulling enough air. Guess not. Soot mean not enough air ? Also if I could not find fire cement isn`t mortar with perlite safe after it is entirely dry ?

      Delete
    3. Hi Ted.
      I wouldn't recommend the mortar, I belive there is a risk of it exploding, but it sounds like you have already used it with no issues.
      I guess your flame is yellow which is lack of air
      ,you could try blowing air in the back with a hairdryer or leaf blower. Maybe the burner is just too small.

      Delete
  99. Thanks so much. Sure do appreciate such a gifted person sharing with the rest of us. I can`t see the color of the flame really. Or I hadn`t looked. I have been using the lid on the furnace. Hoping to get some of your DVD`s or something. Great knowledge.

    ReplyDelete
    Replies
    1. Ted, Happy to help. you can run the furnace without the lid, it just keeps the heat in. I take mine off to add more metal whilst it's still burning.

      Delete
  100. Well this is a very descriptive and informative info you shared here about furnace, I was searching for a furnace emergency service in Toronto, can you please sort one for me... Appreciate your hard work, thank you very much.

    ReplyDelete
  101. Hello,

    Good to see your all the unique techniques. Really liked your work, Thanks for sharing it with us.

    Glass Melt Furnaces

    ReplyDelete
  102. Hi myfordboy i found your blog and videos awesome but i have 2 questions: what are the metals that your furnace can melt? and what's the maximum temperature that it can reach without the furnace takes any damages?
    thanks very much

    ReplyDelete
    Replies
    1. The perlite and fire cement is fine for aluminium but if you want to melt bress or bronze a commercial refactory would be better to use. The furnace will reach the temperature required to melt these OK.

      Delete
  103. myfordboy
    You are a gem and a blessing who's capacity to share and teach from your own knowledge and experience is one of the greatest amongst human attributes. All of us would do well to learn and take on board your generosity and unselfishness where "we" and "us" is placed well above the selfishness of the "I" and "me" that is rampant in the West and is infecting the rest of the world with its consumption without thinking.
    Your recycle and repurposing of materials is wonderful and FUN.

    We can become creators of what we need.

    Looking back way into my past i clearly recall the two Myford lathes (the grey-blue one for metal and the yellow one for wood) that were located in the school workshop. Now this was Kirkham & Wesham Primary School in the 1950's. The trouble was that by the time i started school in the 1950's those machines were no longer being used to teach: seems as though the curriculum's had changed so we missed out. What a waste. (Though they did still teach tech drawing - oh how i remember the ultimate sin of getting pencil smudges on my drawings. And what about rough lettering...bad, bad boy).

    People overlook the fact that the best way to learn anything is to do, then think, then do again.

    But i am waffling as Poroldchap of YouTube fame would have it (good thing is constructive waffling, i reckon).

    myfordboy be well and always remain in good health both physically and mentally and thank you very, very much me old son. :-)

    Tom Mitchell aka tashammer

    ReplyDelete
  104. Hey Myfordboy,
    I have a couple of questions on the diagram. Is it the same size as the one you made? I guessed that the O with a diagonal line through it meant radius, and I figure out the circumference was 70 inches, and that is what is confusing me. Is your furnace 70" in circumference, it seems a lot smaller than that. I also thought that maybe the one in the diagram was an improved version or something. I am thinking about building a furnace now thanks to you, though all the sheet metal around here is Galvanized, and i don't need a lecture on what that stuff can do to your lungs. Again, is that diagram the exact copy of the one you made? I am very confused.

    Thanks man,

    Jakob

    ReplyDelete
  105. Jakob
    The 0 with the diagonal line is the engineering symbol for diameter not radius. This means the circumerance is aprox 35". The drawing is the same as the one I made.

    ReplyDelete
  106. BTW If anyone has trouble finding 100ltr bags of perlite try a hydroponic shop (You know the places that sell growing accessories for "tomatoes"), I tried 4 large garden centres and they only had overpriced 10ltr bags (from £5 to £9 a bag !) the local hydroponic shop (which I should have tried first as it's right round the corner from me!) had 100ltr bags for £15

    ReplyDelete
  107. Hi there Dude,awesome vid,got a lonmg why to go to ur level but looking forward to it,could u tell me pls,1st,why the sand so black,isit a particular type of sand u using,any type u would recommend,and would u recommend a pottery pot furnace or isit a waste of time,i am really amped to start building 1 to melt down rusrt nails and skrews,alot of vintage tools and bits that doesdnt have any purpose anymore,and then just lastly,would rust interfere with the melting prosese or would io be able just to scoop it of the top as i would do with the impureties before a casting,pls could u come back to me on this,thanx for ur time,regards,jacques

    ReplyDelete
    Replies
    1. jq,
      The sand was a dark brown but has darkened with age. It's a foundry greensand. I now have a batch of different stuff which is more orange.
      A flowerpot furnace fired with charcoal is a simple way to start but no way are you going to melt those nails even in a furnace like mine. Steel needs a much higher temperature and is not good for casting anyway.

      Delete
  108. This post is different from what I read on most blog. And it have so many valuable things to learn.

    Heating and cooling Mississauga

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  109. Great post, and this was really interesting to read about. And this post made it look really easy to build a furnace. So if the time ever comes where I need to make one then I'll know where to come for help.

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  110. Thanks for the sharing of such information we will pass it on to our readers.

    High Efficiency Furnace

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  111. Outstanding info you shared here i really impress it.. High Efficiency Furnace Toronto

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  112. Very nice and informative blog Gas FurnaceThis is really a great source of info about HVAC thank you very much for sharing.

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  113. Wow, I love to construct such similar furnace, looks sturdy. Have made that DIY?

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  114. Hi myfordboy Nice working.. This is really fantastic blog i like it...High Efficiency Gas Furnace

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  115. MDB Mechanical commercial heating and Cooling can supply HVAC services and HVAC equipment designed around your business.

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  116. Hi there,
    I read your post myfordboy's furnace and also the pictures they are very nice. But how you get the idea to build your own furnace by your self. I definitely share it to others.

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  117. Hi myfordboy, i have built a gas furnance, it starts nice but when I put the cover top the fire ceases, I am using natural gas, do i need to use propane? or it might be the burner? please help!

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    Replies
    1. The gas should be fine you just need a different jet size than the one for propane.
      There is a hole in the cover isn't there?

      Delete
  118. It would be really cool to get my furnace running off of geothermal energy.

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  119. Thanks so much for sharing this great information! I have been trying to find really reliable furnaces in Vancouver... Hopefully I'll be able to find something perfect for me soon!

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  120. Wow. That is a nice project MyFordBoy. I have a project of my own. I bought a fixer upper apartment complex and I want to build a unit like your in the basement. Also it has a nice Heil Gas Furnace in it. I may refurbish it or sell the furnace unit or parts.

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  121. When it was time to change my gas furnace back in November, I choose a Heil Gas Furnace because it is 95% efficient. Also I look at the parts and they are cheap. Here is where to find cheap Heil Furnace Parts

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  122. I am glad this was useful information Heating and cooling Toronto

    Heating and cooling Toronto

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  123. Wow, I wish I could build something like that. It would save me money to build my own furnace. I am probably going to just get mine from Custom Comfort Inc.

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  124. When I saw this, I thought it could make a good science project for my son, but then it got a little to expensive for a science project.
    Harlin | http://www.giddens-heating-airconditioning.com

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  125. Thanks for nice sharing. You can also find best Cast Iron material at Laxmi Iron & Steel Industry. The main object of LAXMI IRON & STEEL INDUSTRIES is to provide best quality and cost effective Cast Iron. For more information Visit Cast Iron Soil Pipe.

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  126. Oh that's cool mini furnace, how long is the curing time for the cement and the cement proportions?

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    Replies
    1. It could take a week or so to dry, it needs to be done slowly to prevent cracks.
      The method and materials are in the description.

      Delete
  127. Hi David!
    Very nice and descriptive report on furnace performance. Thank you for sharing.
    I really appreciate it.

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  128. These are very useful pieces of information that will be of great use to me in a good position future Pretty. I came across your blog and wanted to say I really enjoyed reading your blog. Either way I will subscribe to their feed, and I hope to publish soon. Thanks for all the hard work. I really appreciate your professional approach.

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  129. Hi Mr myfordboy,
    Just cams across your page today and have been educated a lot. I live in Nigeria and have made a furnace using information Gorton from the net. I'm having some problems with my and wish you could help me out.
    1. I could not get hold of any fire clay or fire cement so had to make my own mix by locating some very white colour clay from a bog near my place. Mixed it 50/50 with some white sand for refractory. This was used to make my insulation and also for roof. The tin is my roof is crumbing apart in large sections but the body insulation is very stable. I was thinking if the reenforcement in the roof has any thing to do with that. PS the roof had very big crakes when drying which I did not patch before firing just to see what I out come would be. I use diesel fuel and was able to get the furnace to light yellow colour ,and the riff can very white from the heat I could generate with that type of fuel.is it rough to use diesel as I think I may have passed the firing temperature for my refractory mix

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    Replies
    1. I have only used propane fuel so have no experience with oil firing.
      For the the lid, on mine I passed screws through from the outside and then fitted some wire to the screws to form a reinforced mesh, to support the refractory. Some builders have suggested though that this can make the lid crack as the reinforcement will expand when heated. As you suggest the heat from your burner could be too great although you say the furnace walls are intact and that is where the heat from the burner hits.

      Delete
    2. Myfordboy,
      Thanks for quick responds, in my lid I use 5mm rods for the refractory in the former and I placed the rods very close to the exit hole. Could this have anything to do with the falling apart of the insulation, also the refractory shrinked alot any adverse as to reducing this, my refractory composition is just clay and sand

      Delete
    3. The way to prevent cracks is to dry slowly although you could still get some. Some builders have used polystyrene beads mixed with the refractory which burn out and leave voids. You could try just clay and beads and a little less metal in the lid.
      Only a suggestion as it is something I have not tried myself.

      Delete
  130. Thanks myfordboy,
    Would using saw dust in place of polystyrene work as it is more readily available in my part of the world as I read in some forum and what will be the composition of the mix using sand and clay and the above saw dust. My first mix of sand and clay weigh so mush.

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    Replies
    1. I have also heard of sawdust being used so you could try that. Worth a try for a new lid.

      Delete
    2. You are on your own really as I have not done this. Your clay and sand held up well though so I would suggest keep the same ratio of sand and clay and and 25% sawdust by volume to the mix.

      Delete
  131. Would give a try and get back to you on the result. What composition would you suggest for the mix using only sand, clay and saw dust

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  132. Myfordboy, i follow u a long time ago and im very surprised to your work, you are a role model. I want to make this foundry but I have a doubt, you made a hole in the bottom of the casting? is to improve the air intake?

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    Replies
    1. The thinking behind the hole and channel was to allow any spilt metal run out the bottom of the furnace.
      In fact it did not work because when some metal was spilt it cooled in the hole and blocked it up.
      My commercial Kasnit furnace has no drain hole so I suggest either leaving out the hole or increasing the size to about 1 1/2" and making it tapered, larger at the bottom.

      Delete
  133. That's an awesome little home built furnace. I'm actually really glad that you included the things that went wrong. It helps us know when we have to stop and go back, or start over. I may try this out for my sister's apartment. They really need a furnace. Thiago | http://www.shortysplumbing.ca/furnaces.html

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