The Sand Casting Process
While the American Brake Shoe Foundry of Mahwah was known for the manufacturing of brake shoes for railroad tracks, the Foundry also produced other items. A very important step of the brake shoe manufacturing process is the creation of a melting pot from a sand casting mold. Sand casting molds were very cost efficient for American Brake Shoe, and were created daily at the Foundry. The purpose of the sand cast molds was to shape metal at high temperatures into melting pots that could be used in the foundry. Since this was such a major part of the American Brake Shoe Foundry, in the 1940s F.S. Lincoln took company photos of the sand casting process. He used Foundry worker Frank “Bunny” Gannon in the photos. Sadly, there is very little information on Bunny Gannon, as he most likely commuted to Mahwah for work. Regardless, he can walk us through the sand casting process.
Bunny Gannon is taking the first step in making centrifugal casting core with Osborn jolt-rockover molding machine. The sand is carefully mixed with core oils as well as clay, and packed tightly. A cereal binder is packed firmly into the pattern, to create a mold for metal to be poured into later.
Bunny Gannon is now smoothing out the sand mixture of the mold. You can see the pattern that the mold will produce in the center of the sand casting.
Some molds required more sand casts to be made. Pictured are Lennie Busch and Benny Dembrowski packing sand and clay into multiple sand casting molds in order to have enough volume to make a very important item, a melting pot. The melting pot has to be cast thick enough to hold molten metal, but thin enough to reduce the part volume to accelerate the cooling process.
Back to Bunny moving one of the melting pot sand casting molds under a safety hood for the casting process. This is done to ensure that the melting pot cools uniformly to reduce defects in the melting pot.
Pictured are Bunny Gannon and Ernest Busch removing the pattern of the melting pot. By splitting the mold into two pieces, they are able to retrieve the newly formed melting pot. But the melting pot that comes from this mold isn’t the finished melting pot pictured in the right corner.
The melting pot is first put on a Vibrex shakeout machine. Bunny Gannon is shaking out remnants of the sand casting from the mold, and the bits of sand and clay fall through the holes in the machine to be gathered for future molds. After this process the melting pot is essentially complete.
Ralph Trimble, George Watson, and Ed Kaulback are pictured using a melting pot to pour molten metal into a mold for brake shoes. This was done in the Metallurgical experimental foundry building at the factory.