This how I make my moulding flasks.
I use simple wooden boxes for my moulds. A pair of boxes is called a Flask. The lower box is known as the Drag whilst the upper box is called the Cope.
Four pieces of wood are used for each box and are screwed and glued together.
A line is added to one side of the pair with a marker pen. This makes sure you re-assemble them the correct way around after removing the pattern.
and short lengths of 3/16" steel rod.
On the the side with the single hole a 3/16" drill is used to open the hole a little.
It's safer to hold the block in a vice whilst this is done.
The blocks are fixed to the wood with a couple of screws.
The use of these blocks gives a very positive location of the cope and drag. The pins can be pushed out before seperating the flasks which makes it easer to seperate.
It is sometimes recommended that grooves are made on the inside of the boxes to provide a key for the sand but I have not found this to be necessary.
The only time I had a problem with the sand slipping out from the flasks was in my first attempt at moulding when through lack of experience I made the sand way too wet.
It seems that modesty blocks are not available in some parts of the world including the US.
As a service to help others I can supply 16 blocks and airmail them anywhere in the world for £5.00. (5 GB Pounds) .Pay by Paypal.
The blocks are sold here in the UK in DIY stores for joining two sheets of furniture board or wood together at right angles. The term modesty blocks originates from mixed office environments where panels were fitted between desks to "preserve ones modesty"
25/03/13 Update
I have made up a number of new flasks using softwood decking. The timber is harder than the rubbish we get here as a general building material and has grooves on one side which is desirable as it helps the sand grip the flask sides.
A further refinement is to used different coloured blocks on each side, they are available in brown or white.This is a further aid to assembling them the correct way around after the pattern has been removed.
The video of the construction is shown below.
The blocks are sold here in the UK in DIY stores for joining two sheets of furniture board or wood together at right angles. The term modesty blocks originates from mixed office environments where panels were fitted between desks to "preserve ones modesty"
25/03/13 Update
I have made up a number of new flasks using softwood decking. The timber is harder than the rubbish we get here as a general building material and has grooves on one side which is desirable as it helps the sand grip the flask sides.
A further refinement is to used different coloured blocks on each side, they are available in brown or white.This is a further aid to assembling them the correct way around after the pattern has been removed.
The video of the construction is shown below.
