I'm fixin' to try the backyard foundry thing. Found a really good source somewhere (here I think) of a waste-oil fired setup using an old water heater as a base for a furnace. My new house has an old water heater (needs replaced). I have access to plenty of waste oil and used pistons from work. And therein lies the question. When melting used pistons, there seems to be several potential issues - contamination from carbon deposits an oil embedded in the surface of the old piston, and how to get out the steel pin supports. I'm thinking an hour or 2 in the vat will solve the oil issue, sandblasting will solve the carbon issue, and a sledgehammer will solve the steel plate issue. However, that all sounds very labor intensive for 500 or so grams of aluminum per piston. Is there a more efficient way of handling these issues? I am planning to start out by just making ingots (hopefully relatively clean ones). Then, when I am actually casting a part, it should go smoother. Will the contaminants all come out as slag, or is it worth it to go through the trouble of thoroughly cleaning the pistons first? And has anyone tried a method of melting the whole piston, with some way of pulling the steel plates out after the aluminum has melted, or is it really better to sledge them to death and separate the metals first? My first parts will probably be replacements for thoroughly wasted plastic parts on one of my daughter's projects. Inner door handles, dash parts, etc., (sort of OT cuz it's foreign, but it is a '60) so contamination should not be a huge problem there, but I would like to start out right from the beginning. Later, I will be doing stuff like wind shield posts for her '19, and maybe some bits for my '53, where integrity of the casting will be more important. Thanks Chris
Ya planning on making investment moldings then from parts to repro as well? Or are you going with sand? IMO you would be steps ahead to use a propane forge and crucibles. Don't use a ladle, used one for copper years ago and melted through it. I had plans for a propane forge laying around here somewhere... But lost 'em
From what i've read on the internet the crap floats to the top and you skim it off,try homecasting .com or something like that
if you're going to pour ingots and then remelt for a casting, just dunk the whole piston in the crucible. Be careful when you pour to not dump the steel out into your ingot mold. When the volume in the crucible is low enough you can pick the steel out with pliers.
What Mopar said. I melted lots of pistons. The dirt becomes slag and floats on the surface. The steel just sits there and I picked it out with pliars. Wasn't castinf structal parts. Pretty brittal result.
I did a bunch of aluminum casting with my cousin when I was a kid, and I kind of remember my cousin throwing handfuls of white powder (I think it was borax) in there as sort of a flux to get the crap in the aluminum to float up to the top. Also he used to throw a few copper pennies into the melted aluminum (when pennies were made of real copper). I'm not sure what the copper was for, but I think it made it easier to machine or something. We made some really nice looking castings. Once in a while we'd pour it when it was a little too hot and the casting would wind up porous and wouldn't polish up well, but usually they polished up really nice like a mirror. You can use those old cast iron cupcake pans to pour the leftover aluminum into ingots.
forget the waste oil heater, i'll make you the deal of a lifetime on a real furance, i do not need it anymore have 2 of them "lindburg hevi-duty"
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