Wednesday, January 13, 2010
Wooden It Be Nice?
Finished making the pattern for the pump housing today. As I stated before, it is three pieces of 3/4 plywood sandwiched together. I used the gasket to trace the shape and I bandsawed it out. The recess was made with a circular pattern and a router. I used my spindle sander to smooth the sides. I tilted the table a few degrees to give it some draft so it will pull out of the greensand mold. I sprayed the whole thing with sandable primer/surfacer and coated it with automotive, lacquer based, spot putty and sanded the whole thing smooth. Another couple of coats of the primer, a bit of finish sanding and there ya go, one pattern. I'll wax it before I ram up the mold. The recess was made slightly conical with some Durham's Rock Hard Water Putty so it too will have sufficient draft to release from the sand. I could have left out the recess and machined it, but that's a lot of extra work
While I was whittling, I made a pattern for the pulley. I could have gone to Pick a Part and, possibly, found one that would work. I figured I could make one in less time and for free. Plus, I get extra bragging rights for making my own stuff.
Today I got some pictures emailed to me by a V-8 biker that built a pump similar to mine. His and mine are almost identical. Since I consider him to be a bit of a genius (though not a Boy Genius™), I feel my design is a good one and should work flawlessly. He also offered some suggestions to make the entire unit more compact. Since this would involve machining the pump housing, I have opted to keep the original size pump. I expect that it will never give me a bit of trouble, but if it does and I need to change it, I don't want to have to cut down another pump, especially if I'm stuck in the middle of nowhere.