Brass Step by Step
Molding and gating is the same for aluminum, brass and bronze. Follow these basic instructions for most projects. Aluminum is easiest to learn with as it melts, cuts, files and polishes with less effort than brass or bronze.

 Pattern, flask and pattern board. The pattern board is placed between the cope and drag. When you are finished with the mold, the cope is the top and the drag is the bottom.

Dust pattern with parting dust in the drag.

Completely cover pattern with fine riddle.

 

Completely covering the pattern using the fine riddle will insure fine detail.

Fill the rest of the drag using the coarse riddle.Fill mold flush with top of drag.                The coarse riddle (seive) has 1/4" holes, this fluffs up the sand so it rams evenly. You do not need to use the coarse riddle if you make sure most of the lumps are out and the sand is "fluffed".

Ram edge of mold with paddle rammer. This will prevent leaks.

Ram with peen side of rammer. North to south and then east to west. Not real hard, but evenly. Soft on the first ram and slightly harder each time you ram.

Then fill the mold (without riddling), to about 2 inches over the top.

Then ram with the butt side of the rammer, a harder ram.

Strike off drag leaving a small amount of sand to cushion bottom board.

Place bottom board on drag section and flip the mold over.

Remove cope section (empty) and pattern board.

When placing pattern stay at least 1/2 inch away from edge of mold.

Smooth the sand with a molding spoon around pattern and rough areas. On items with uneven parting lines carve down to the parting line.

Mark the location of your sprue by slightly pressing the cutter into the sand.    

Replace cope. Apply parting dust to keep cope and drag separated. Note sprue (0) and pop-up (X) location.

Cover back of casting with fine riddle for fine detail, coarse riddle if you don't mind a slightly rough finish on the back.

Fill cope section flush to top and use paddle rammer to tuck edges.

Ram with peen side pointing east to west, then with north to south, firm and even, not too hard. Soft the first ram and slightly harder each additional time.

Fill cope 2 inches above top and ram again with the butt side of rammer. Then the cope is struck off and slicked smooth with a trowel.