Copper scrap for bar casting

[Shazbot57]

I've been collecting copper scrap in the form of wire, pipe, old busted inoperable equipment/appliances, etc. from random dump sites and curbside trash for years in the course of errands/work and just set it aside. I have a sizeable pile and an idea that has been bouncing around in my head was someday building a homemade forge/smelter, buying a few casting molds and casting some copper bars (maybe lead & aluminum also) for grins & giggles. Thought they might make interesting conversation pieces, paperweights, doorstops, gifts etc.

I know there are members who cast copper, silver and other metals as bullion bars as part of their businesses. This is not meant to compete with their endeavors, or meant for resale. I'm just looking to putter a bit. I've seen you tube videos on how to make melting furnaces out of various objects like old propane tanks, etc.

So here's the question: Any thoughts about, or advice on how to go about this, or past experience anyone cares to share. All input is appreciated!

[hobo finds]

I think it would be easier to sell the copper scrap at a scrap yard than a bar made out of copper scrap. But they go for good prices on EBAY...

[Shazbot57]

I think it would be easier to sell the copper scrap at a scrap yard than a bar made out of copper scrap. But they go for good prices on EBAY...

I would tend to agree, it would be easier, but selling the scrap for money wasn't that important to me. Was just thinking about doing something more interesting with the metal... And I really wasn't planning on making these to sell, (at least not anytime soon that I can foresee).

[natsb88]

If you've never melted/poured before, first practice with something easier and more forgiving like aluminum. You can work at ~1300 degrees and your castings should stay pretty clean. With copper you will be over 2000 degrees and you'll have a black crust from oxidation to deal with. Copper is one of the more challenging non-ferrous metals to work with. It's pretty borderline for backyard casting IMO. I would not recommend it unless you are mechanically inclined, safety conscious, and get good at melting and pouring aluminum first (or even silver if you are working small scale).

Be careful what you melt. Crap in = crap out. Pipes may be contaminated with solder and corrosion/oxidation from whatever was flowing through them, motor wire is coated in varnish/lacquer/enamel, watch out for connectors and insulation on wires, etc. Some contaminants will burn off (don't breathe it), some will float to the top, anything metallic will mix in and lower the copper purity. If you want to be able to stamp it "999 fine" you will not be able to use random scrap, and once you melt non-pure metal in a crucible you can never be assured of pouring pure metal out of that crucible again, even if you use 999 stock.

Wear safety gear! All-cotton clothes with long sleeves and pants, then a flame-retardant jacket, face shield, high temperature gloves, etc.). Be aware of what is around you and under your feet. The radiant heat from the crucible (or dropping/spilling copper) can easily set grass, wood, and anything else flammable on fire, and of course can severely injure you. I once stayed in the heat of an oven too long and crazed the lenses in a pair of prescription glasses

[Sheikh_yer_Bu'Tay]

If you've never melted/poured before, first practice with something easier and more forgiving like aluminum. You can work at ~1300 degrees and your castings should stay pretty clean. With copper you will be over 2000 degrees and you'll have a black crust from oxidation to deal with. Copper is one of the more challenging non-ferrous metals to work with. It's pretty borderline for backyard casting IMO. I would not recommend it unless you are mechanically inclined, safety conscious, and get good at melting and pouring aluminum first (or even silver if you are working small scale).

Be careful what you melt. Crap in = crap out. Pipes may be contaminated with solder and corrosion/oxidation from whatever was flowing through them, motor wire is coated in varnish/lacquer/enamel, watch out for connectors and insulation on wires, etc. Some contaminants will burn off (don't breathe it), some will float to the top, anything metallic will mix in and lower the copper purity. If you want to be able to stamp it "999 fine" you will not be able to use random scrap, and once you melt non-pure metal in a crucible you can never be assured of pouring pure metal out of that crucible again, even if you use 999 stock.

Wear safety gear! All-cotton clothes with long sleeves and pants, then a flame-retardant jacket, face shield, high temperature gloves, etc.). Be aware of what is around you and under your feet. The radiant heat from the crucible (or dropping/spilling copper) can easily set grass, wood, and anything else flammable on fire, and of course can severely injure you. I once stayed in the heat of an oven too long and crazed the lenses in a pair of prescription glasses

I am also interested in converting scrap copper into bars for long term storage. It is my hedge for the eventual dollar collapse. scrap copper is cheap now. Some day it will be much higher. Please tell us more. I too have watched the YouTube vids on backyard foundries. There is a lot they leave out and most make bars far less then 99.9 pure.

EDIT: natsb88........After re-reading and thinking about what you have written, and visiting The Copper Cave a few times, the biggest question I have is this: What is the difference between "999 fine" and "#1 Bright Copper"?

[AGgressive Metal]

#1 and #2 are scrap industry terms not exact purities, #1 Bright is basically stuff that looks completely copper and is clean and bright, like a new 1/2" copper pipe from Home Depot, ie the best you can do short of actually assaying the stuff. A ton of material that leaves a scrap yard as #1 Bright is still going have some impurities due to human error or stuff that looks right but wasn't cast out of true 999.

[natsb88]

EDIT: natsb88........After re-reading and thinking about what you have written, and visiting The Copper Cave a few times, the biggest question I have is this: What is the difference between "999 fine" and "#1 Bright Copper"?

In theory, #1 bright copper should actually be 999 fine. #1 bright copper is to be only unalloyed, uncoated copper wire, 16 gauge and larger, free from any tarnish. No pipe, no bus bars, no connectors, no sheet stock, no paint, not burnt, no varnish or insulation remnants, etc. However, many scrap yards and recyclers have their own definitions for #1 bright that are more lax. They may include other forms of copper like pipe/tubing, thinner wire, and copper with some minor oxidation, but throwing those into the mix can drop the purity below 999.

If you stick with clean, uncoated wire scrap (other forms only if you know the source and alloy), melt in a new, clean graphite or ceramic crucible, and pour into a clean mold, your copper should stay 999 fine, but you will still have to deal with rapid oxidation.

[Sheikh_yer_Bu'Tay]

EDIT: natsb88........After re-reading and thinking about what you have written, and visiting The Copper Cave a few times, the biggest question I have is this: What is the difference between "999 fine" and "#1 Bright Copper"?

In theory, #1 bright copper should actually be 999 fine. #1 bright copper is to be only unalloyed, uncoated copper wire, 16 gauge and larger, free from any tarnish. No pipe, no bus bars, no connectors, no sheet stock, no paint, not burnt, no varnish or insulation remnants, etc. However, many scrap yards and recyclers have their own definitions for #1 bright that are more lax. They may include other forms of copper like pipe/tubing, thinner wire, and copper with some minor oxidation, but throwing those into the mix can drop the purity below 999.

If you stick with clean, uncoated wire scrap (other forms only if you know the source and alloy), melt in a new, clean graphite or ceramic crucible, and pour into a clean mold, your copper should stay 999 fine, but you will still have to deal with rapid oxidation.

I have a buddy who runs an aluminum casting foundry. I have tried to get him interested in copper for years. He always comes up with reasons it is not cost effective to make 999 fine cu bars. He knows his stuff, too!

I guess using electrolysis is the cheapest way to transform scrap into 999 fine. To do that in quantity would make for a very high electric bill (and maybe a visit from some government agency wanting to know if you are growing weed )

To avoid rapid oxidation I guess placing the crucible in an enclosure filled with an inert gas (heavier than air) before you pour would keep oxygen out during the pour. Right?

[Sheikh_yer_Bu'Tay]

Thanks for the great advise natsb88. All the bars I pour ( IF I ever get around to it. It may be that I have Wilson's Disease and have to give up Cu ) will be like those guys in their backyards. 95% of all my scrap is #2 copper. If I ever decide to step up to 999 fine, I will know who to buy it from.

[natsb88]

To avoid rapid oxidation I guess placing the crucible in an enclosure filled with an inert gas (heavier than air) before you pour would keep oxygen out during the pour. Right?

If you could melt and pour entirely in an environment free of oxygen, there would be no oxidation to clean up. That is more challenging than it sounds, particularly if you are using combustion to generate the heat to melt your copper.