Ingot Molds

IMHO the cheapest easiest ingot molds are made out of angle iron or channel iron. If you have an electric welder, they are easy to make and cheap and sticking will not be a problem. Cut ends of angle iron or channel irons on an angle of approc 3 to 5 deg for draft, and weld on a piece of strap or flat iron. You can gang a couple of them together. Extend the flat iron thats used to cover the ends of the channel or angle iron and attach a p iece of rod or pipe to it so it forms a handle.....Works great and takes a beating.

Or if you have green sand you can simply inbed a ingot pattern or whatever into the green sand and pour them that way, of course you have ot make a new mold for each ingot, but if your not doing a lot of ingots its not a big problem.

You'll soon find cans and other thin materials are bit the greatest for melting due to all the surface area and tons of dross you get, but hey, its certainly better than twiddling your thums with nothing at all to melt down........

regards '

============================================== Put some color in your cheeks...garden naked! "The original frugal ponder" ~~~~ } ~~~~~~ } ~~~~~~~ }

Any idea for getting the aluminum ingots out of the muffin pan? I tried a torch to the bottom, but all I have is a little bernzomatic oxy/mapp thing (and various propane torches, including the foundry burner), and it didn't seem to do much.

The individual cups are crimped into place, and prying on the ingot actually popped the whole cup out. I guess if it comes down to it I can melt the cup with the ingot in the foundry when I want to use them, then fish the cup out.

CHAR YOUR INGOT MOLDS THE FIRST TIME PEOPLE!!!!!!!!!

Sorry but honestly, what the hell makes people pour into a virgin muffin tin that is designed for cooking food, not metal. The paint (ESPECIALLY if teflon coated, try that poison on for size) burning off under the metal is just BEGGING for an explosion.

Tim

As Roy said, use a heavier mold to start with and use a better quality of scrap. Stuff like beer cans is very inneficient scrap, even when done on industrial levels with baled or briquetted cans. The bottom half of the cans is good stuff, but the tops are a crummy alloy that you'll probably find to be quite slushy.

If your mold gets too hot the aluminum will bond with it, either through warpage or like brazing. Even iron, given some time, will dissolve in aluminum and I think what you're getting is your ingots effectively brazed to the muffin tins. A heavier mold won't get to as high a temperature and you'll likely get better results.

John

Nah, the cans overall melt to approx. 3% Mg, balance Al. Which... really isn't very useful anyway. Burn out 1-2% of the magnesium, add 1-2% copper and 10% silicon and you've got yourself a skookum casting alloy. Just need to find silicon...

There's a *lot* of metal in cans, more than you'd think. I mean, individual cans are piss-poor on metal, but more than half the slag still contains metal. To get it out, you need to add a flux. Salt is a good flux for aluminum, or better yet, a lower-melting mixture such as half and half NaCl

• KCl (potassium). Throw it on, stir, wait for the salt to melt, add enough that it becomes a soupy mess, then pour everything. If you want aluminum oxide for any reason, it can be seperated from the salt by soaking in water.

I'd be more inclined to call it soldering.. it's a pretty weak bond. 'Course it won't get a bond in the first place if your steel is rusty or covered in scale, which is why you need to char your steel items before any contact with aluminum.

Doesn't take much time, pure aluminum eats non-charred soup cans for breakfast. At 1450°F, aluminum has about 4% solubility for iron (which later comes out as brittle Al13Fe4 or if silicon is present, a three component AlFeSi intermetallic).

My 1/4" thick angle iron regularly gets red hot, the problem is how clean the interface is. I use the damn rustiest angle in my scrap pile and there ain't a damned thing gonna stick to it.

Tim

-- "California is the breakfast state: fruits, nuts and flakes." Website:

Muffi8n "tins" like soup cans are iffy at most when using them as crucibles or ingot molds, charred or not. They do not take any kind of rap without denting, so those dents can also impede removing ingots from a muffin tin. The cast iron corn bread molds work fine, if you don't mind having a heap of ingots looking like a slice of corn on the cob etc. Tin is just too thin and it reacts too much with what poiured in there other than cake or muffin batters.......

I quit melting cans a long time ago its just not worth it, having to diddle around to make what you get worthwhile with or without flux, best to sell the cans and get the money.....or trade them for some previously cast aluminum scrap.......

============================================== Put some color in your cheeks...garden naked! "The original frugal ponder" ~~~~ } ~~~~~~ } ~~~~~~~ }

Or.. you could start with a different alloy;-)

Again, I think I'd start with heavier chunks.. although the oxide might be useful. Seems a can is about an ounce, and there's a lot of surface area there to oxidize..

Maybe a coating of carbon from a torch? Careful with the rusty steel, a little water makes for impressive results. The aluminum foundry I worked in had some fairly large water cooled sow molds, around 600lb. ingots.. when they'd accidentally pour a wet mold the aluminum would hit the roof pretty hard, about 20' above. The help would scatter amidst considerable verbal abuse directed at whoever slipped up, the aluminum would continue to run, etc. It was sort of a hoot, when nobody got burned.

Now that you mention it, I remember a guy who liked to throw coathangers and or banding in the melt when the iron content was adequately low and they were waiting to bring the alloy to spec., didn't take long for them to dissolve. The point was simply to increase the number of pounds in the furnace cheaply.

With small ingots I think you're onto something. Again, most of my experience is with ingots of 25lbs. and up- these have adequate size to shrink considerably, relative to the mold, and would come out of a clean mold fairly well. Usually..

Been there. Works great. I used some angle iron (40 * 40mm), welded them side by side to have something like a shuffle board and closed the ends with a flat. No prepping before poring. The steel was HRS.

Nick

True, but their value as scrap is greater than the yield. Seems to me a guy could come out much better by selling the cans and buying scrap cast aluminum, perhaps from the same source. Still leaves you with the *fun* of melting and casting ingots, but without the tremendous loss. The bonus is to end up with aluminum formulated perfectly for casting, very unlike melted cans.

The other thing I'd comment on is using ANYTHING with a thin wall for a mold. Muffin tins are that, muffin tins. The idea of using them for molds for molten metal is insane. As Roy said, it's way too easy to make a mold that won't over heat, preventing your metal from fusing. Using angle or channel iron is especially good, because the mill scale makes bonding of the molten metal all the more difficult. If you find you're having trouble with fusing, you can easily blacken the mold with an acetylene torch, or brush on a mold release mode of lamp black. Foundry supplies carry that product.

Harold

laying down a layer of soot from an acetylete torch to act as a mold release. Not sure how the carbon might affect future melts if it doesn't brush off though. Anyone remember where soot was used like this? Also curious also how it would affect the AL on future melts. Comments?

Koz

Very true. My scrapyard will pay about $1.30/lb for cans and sells me diesel pistons for less than a dollar a pound. Any day, every day.

Which would you rather cast with?

I seem to remember

Soot from any source has been a standard mold release for many people who mold lead figures and lead bullets. The "smoked" mold can have the soot applied with a candle or a torch set rich. It works very well and most of the soot remains on the mold.

Thanks for the many tips guys. I'll get some cast iron cornbread molds and will smoke them up with a rich torch first.