Melting soup and coffee cans for casting?

[gambit]

I was sorting out soda cans from my recycling bin and realized that we recycle
alot of soup and coffee cans. I didn't want them to get tossed if I could melt
them so I did some googling to see what they are made of. Apparently they
are made of steel (with a small percentage of tin added for corrosion
resistance) and sometimes aluminum and other metals. Campbells has said their
cans are steel. I would really like to know if anybody melts anything that is
usually recycled in the home other than soda/beer cans and the other obvious
aluminum products?

[awerby]

Even if you did have a cupola furnace that would melt steel, you'd want steel that was of a known castable alloy, not a mixture of whatever's in cans. And even aluminum cans, which melt at a much lower temperature, are poor candidates for remelting, since they have so much surface area - they mostly produce aluminum oxide and fumes from burning paint.

One creative idea, if you want to do something with your cans, is to make candle lanterns out of them. Fill them with water and freeze them, then use a punch to put decorative patterns in them, that the light from the candles can illuminate (once you pour out the melted ice).

Andrew Werby
ComputerSculpture.com — Home Page for Discount Hardware & Software

[keebler303]

Good idea on freezing water inside them. In the past I have just used a tree limb as an anvil to prevent denting the can.

Matt

[gambit]

Even if you did have a cupola furnace that would melt steel, you'd want steel that was of a known castable alloy, not a mixture of whatever's in cans. And even aluminum cans, which melt at a much lower temperature, are poor candidates for remelting, since they have so much surface area - they mostly produce aluminum oxide and fumes from burning paint.

Can a DIY cupola furnace melt steel? And what type of fuel would you need?

[DMF_TomB]

I was sorting out soda cans from my recycling bin and realized that we recycle
alot of soup and coffee cans. I didn't want them to get tossed if I could melt
them so I did some googling to see what they are made of. Apparently they
are made of steel (with a small percentage of tin added for corrosion
resistance) and sometimes aluminum and other metals. Campbells has said their
cans are steel. I would really like to know if anybody melts anything that is
usually recycled in the home other than soda/beer cans and the other obvious
aluminum products?

.
my experience melting aluminum cans is
.
1) fumes from pop can from "paint" are highly polluting without pollution control equipment
.
2) the aluminum tends to be heavily oxidized
.
3) easy to over heat metal and pick up hydrogen porosity from contaminated cans, fuel, water

4) cost of fuel may be more than cost of aluminum even if pop cans were free.

industrially the melted metal has nitrogen or toxic chlorine gas bubbling through the molten metal to reduce porosity. powerful chemicals help with fluxing oxides to surface, to be skimmed off and oxides maybe of use for other things in large quantities. industrially the metal is analyzed for alloy content as purer aluminum like in cans has low strength for machine parts.
......... Mao a leader in China thought every small village should have a blast furnace to make cast iron parts. After awhile they realized they had many small factories producing fairly low quality product. Efficiency experts recommended larger but few factories where unit cost is cheaper, quality is higher from better equipment design and more technical production expertise, and pollution is easier to try to control.

[gambit]

@DMF_TomB

I take it that you use to melt pop cans?

It sounds like you may not anymore. What sources of aluminum and other metals do you use?

[Joe S.]

I melted soda cans once, first last and only time I will do it. Lost pretty much 1/2 the weight to oxide & slag, better off selling them and buying aluminum. Good scrap is old auto parts like trans cases, water pumps, and other cast parts. High silicon aluminum, casts better than cans.

[gambit]

I guess I might as well toss the bags of cans and start stripping down some of the old cars on my property. If I was to save the cast iron engine blocks, I wonder how easy they would be to cut them down for melting?

[DMF_TomB]

@DMF_TomB

I take it that you use to melt pop cans?

It sounds like you may not anymore. What sources of aluminum and other metals do you use?

.
junk yard sells metal. be warned magnesium and aluminum are difficult to tell apart. best thing to get is little short pieces cut off leftovers from a place that sells aluminum or a machine shop. best stuff still has markings like 6061 (a type of aluminum)

[gambit]

.
junk yard sells metal. be warned magnesium and aluminum are difficult to tell apart. best thing to get is little short pieces cut off leftovers from a place that sells aluminum or a machine shop. best stuff still has markings like 6061 (a type of aluminum)

What kind of product at the junk yard would I want to avoid so I don't make the mistake of buying unwanted magnesium.

[DMF_TomB]

What kind of product at the junk yard would I want to avoid so I don't make the mistake of buying unwanted magnesium.

there is no easy way to tell aluminum from magnesium. magnesium when hot enough will burn by itself when exposed to air. i melted some with aluminum and when i took furnace lid off and the air hit it it started burning with a bright white light.
.
i used the heel of my shoe to dig grooves in the dirt and poured it into grooves where it continued to burn so i covered with more dirt. it smoldered for at least 10 minutes.
.
old story a junk man found a glowing piece of metal in junk equipment. he took it and showed it to every body including family. it was radioactive metal from hospital cancer treatment equipment. he gave radiation poisoning to his whole family. most bigger junk yards have a radiation geiger counter meter now. ...... you never know what you will find in a junk yard

[gambit]

I guess if I had to mistake magnesium for aluminum or radioactive material, I would definitely be happy magnesium. I just don't understand why someone would even think twice about wanting to be within 100 yards of any metal that glows. Common sense would tell you that glowing metal is not right. I could understand curiosity may get you close to something like that, just to make sure you were not seeing things, but why would anybody touch it. In this world, some people just get smacked with the stupid stick a lot harder and often than others.

It's kinda scary to think that a hospital could be that irresponsible. I would think with the money a hospital makes, they could afford to dispose of radioactive materials properly.