In making any kind of castings you need a flask, that is a wooden frame made in halves, as shown in [Fig. 40]; the top half of the flask is called the cope and this must be fitted with pins that set in holes in the bottom of the frame or drag, as it is called.
Fig. 40. how a pewter casting is made
When these pins set in the holes they keep the top and bottom parts of the flask together so that after the mold is made they can be taken apart and the pattern removed and then when they are put together again ready for the metal to be poured they will be exactly even. Make the top and bottom halves of the flask a couple of inches larger all round and a couple of inches deeper than the size of the pattern you are going to cast.
The Patterns Necessary.
—You can saw or turn or carve out of wood anything you want to cast in pewter, provided it is not too intricate, and after sandpapering it nice and smooth all over give it a couple of coats of shellac varnish.[33]
[33] This can be bought already made at paint stores or you can make it by dissolving some yellow shellac in alcohol.
If it is your idea to make table-ware of pewter you can use ordinary china dishes for your patterns, provided they are without handles, but before making a mold with any kind of a pattern in plaster oil it well all over with sweet oil, using a brush for the purpose, so that it will not stick and then you can draw it easily.
Making the Mold.
—Lay the drag, that is the lower half of the flask, on a board or a table; mix dental plaster of Paris with water until it is about as thick as batter and fill the drag with it.