Hi all, Now that the winter months are approaching, I can finally get back to metal casting without suffering heat stroke! I bought two large ingots, one casting-grade Al and one SI-bronze, and neither will fit in my largest crucible. Does anyone have any tricks to breaking down large ingots into manageable pieces? All I have is a hacksaw I seem to recall something about heating the ingot up (how hot?) and bashing it with a hammer to break it up.
Maybe close to the malting point it gets soft, then remove it from the heat source (furnace or wood fire), smash it to smaller pieces. Or an angle grinder (which you don't have ?).
Aluminum should be easy to hack up. The bronze is a another issue. It really depends on how big the ingot is. An angle grinder and a pack of thin blades is in your future. If all else fails you can probably find a small machine shop to chop them up for you. I had to do that with my zamak ingots. The first shop I went to it almost broke their horizontal bandsaw and he gave it back to me told me to go somewhere else lol. Second shop used a HUGE chop saw and a lot of lube
It turns out I already took care of the bronze ingot. I guess it was small enough to fit in a crucible. The aluminum is massive though, so I definitely have to break that down somehow.
Two options. Heat to hot short as metallab suggested over an open fire then mash it into pieces. Melt over an open fire and pick up the remains from under the fire. If you build the fire on sand with grooves cut in it you will get a semblance of ingots the size of the grooves.
Aluminum is soft enough that common woodworking tools will work, any type of circular saw with a carbide tipped blade cuts through aluminum with ease. A word of caution though, the chips are hot and sharp so appropriate PPE is mandatory.
Manageable for you maybe, but not when this is my biggest crucible lol The carbide blade idea is interesting. What sort of PPE do you need for high velocity hot metal chips?
As I see your photo of the Al chunk and the crucible, you can use a roofer's roaring burner while putting the chunk vertically on the crucible and than melt it. Some will leak beside, but you can easily collect that when frozen and remelt it all together.
I went with the heating idea, and used my weed burner to heat the ingot up in my fire pit. I bought this to cure my furnace when I built it, and it puts out a tremendous amount of heat. I just blasted the ingot until it just started melting, and used a hammer and chisel to break it up. It had an interesting consistency, sort of like hard clay. It took a bit more work than I was expecting, but I got it into manageable pieces. Next will be to melt these into clean ingots, and then I can use it for projects. Thanks for all the advice!
It looks like your method worked well. Unless there’s a lot of foreign matter mixed in your chunks I wouldn’t bother making ingots. It should be good to go like it is. Pete
Hot short is a very practical way to break up aluminum, but, those pieces have a lot of surface area and now aluminum oxide on the surface. When you remelt it, that will become dross on the surface of the melt and you will loose a little in your yield. Don't skim the dross until you are ready to pour because H2 is soluble in aluminum but not Al2O3 and it acts as a barrier. I agree, I would not mess with making ingots as the aforementioned will occur on the first remelt regardless of what you intend for the melt. Best, Kelly
