With the machine sort of up and running, It was time to stoke up a "little fire" and make the final set of adjustment blocks for the machine.
Last night, I fabricated a tool that looks to be a leap forward in the foundry's process. The device is a KHPT (Kush Head Pressure Tool) which I discovered on this site. The KHPT provides...
1. A clear target to pour into. The smoke makes it very tough to tell where you're pouring and how full you are keeping the sprue.
2. A reservior of molten aluminum above the part that provides pressure to feed the casting as it cools.
After welding up the KHPT, I set up the bandsaw and cut the foam patterns for the adjustment blocks. I made 6 patterns (accounting for my typically high scrap rate). Two of these included the mounting holes to see how well that works out.
Tonight, the foundry was fired up and it was fed most of the block from a donated lawnmower engine along with a few small chunks from previous pours. The temp was cool, so the foundry fed off the cold air and got hot fast. After the foam was buried in sand, the KHPT was placed around the top of the sprue and the hot liquid metal was poured in. I was easily able to hit the target and keep the KHPT about 3" full of aluminum. When the metal in the KHPT became just solid, I pulled it loose from the sprue and split the PHPT to eject the slug. A few minutes later, I pulled 6 perfect castings from the sand... Eureka!
