Place the "cope" of your square mold (which has two interlocking pieces: the cope and the drag) on a flat, clean plastic surface so that the locking mechanism faces down. Place one-half of your molding model -- the item that creates the molding cavity -- in the center of the cope. Coat the inside of the cope with separating powder.
2
Place a sieve -- a mesh grate designed to break large chunks of sand into smaller particles -- over the top of the cope. Pour oiled molding sand into the sieve and work it through the wire mesh down into the cope. Fill the cope most of the way with the sieved sand.
3
Remove the sieve and fill the cope the rest of the way with oiled sand. Break apart large chunks of sand.
4
Compress the sand into the cope using a wooden tamper. Add more sand if the sand level falls below the edge of the cope. It is best to have an abundance of sand rather than too little sand.
5
Ask an assistant to hold the cope steady. Scrape a straight edge across the sand, and remove the excess sand until it sits at an even level with the lip of the cope.
6
Turn the cope over. Add the second piece of the molding model over the first piece embedded in the cope. Line up the edges perfectly.
7
Snap the square moldĄ¯s "drag" over the top of the cope. Coat the inside of the drag with separating powder.
8
Place the sieve over the drag. Force oiled casting sand through the mesh of the sieve until it almost fills the drag. Fill the rest of the drag without the sieve, and tamp the sand down in place.
9
Scrape a flat edge across the top of the drag to even out the sand. Ask an assistant to hold the square mold steady as you work.
10
Separate the drag from the cope. Set the drag aside.
11
Cut two holes (the runner and riser holes) into the sand to the right and the left of the molding model in the cope. Do not make holes in the drag. Use a hollow tube to cut out the holes. Space them 1/2 inch away from the molding model.
12
Pull the molding model out of the sand in both the cope and drag. Do not disturb the sand around the object.
13
Scoop out small amounts of sand between the runner hole and the mold indentation to make a canal. Do the same between the riser hole and the mold indentation. This allows the molten metal to travel from the runner hole into the mold indentation and then into the riser hole.
14
Hold the cope suspended with the mold indentation facing down. Shape it gently to remove excess sand. Smooth out the sand in the canals with your fingers.
15
Set the cope on its side and poke the inside of the mold indentation with a 20-gauge metal stick. Poke all the way through the sand. Poke all along the indentation so no air bubbles can form and prevent the mold from filling completely.
16
Flip the cope so the mold indentation faces down. Set it over the drag and line up the edges on both.
17
Dig a small indentation into the sand next to the runner hole, no more than 1/2 inch deep. Carve out a canal that leads to the runner hole as well. This is where you will pour the molten metal and allow it to seep into the mold.
18
Separate the drag from the cope and remove loose sand from both sides. Reconnect the drag and cope.
19
Don a pair of welding gloves and welding goggles. Lift your container of molten metal and slowly pour it into the small indentation that leads to the runner hole. Allow the metal to seep slowly into the runner hole.
20
Allow the metal to cool for 10 to 20 minutes. Pull apart the cope and the drag and scrape away the sand from the molded metal using a sturdy metal pole. Do not touch the metal until it cools completely.
