Question for welder/metallurgists on Copper

Fittings, parrots, packing, tooling and so on.

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Tōtōchtin
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Question for welder/metallurgists on Copper

Post by Tōtōchtin »

I ordered some copper scraps that came from milling. I have 12 lbs. that I paid less then scrap. When it arrived instead all swirls I ended up with half of it having the texture of sand. My question is, if I put it in a pot and use a cutting torch to try to melt it hoping it beads up. Maybe hitting it with a spray to help with the beading.
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Steve Broady
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Re: Question for welder/metallurgists on Copper

Post by Steve Broady »

What are you hoping to achieve? If you’re trying to cast it into a solid object, you might want to research metal casting. That’s a whole other rabbit hole to go down, just as complex and challenging as making booze.
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Tōtōchtin
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Re: Question for welder/metallurgists on Copper

Post by Tōtōchtin »

No what I want is to make some small pebbles out of it. Originally I wanted to use it to pack a column. Now I want to use it hanging in my boiler/thumper for more exposure. Right now its too fine to use.
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Re: Question for welder/metallurgists on Copper

Post by shadylane »

Tōtōchtin wrote: Thu Jan 26, 2023 9:55 am I ordered some copper scraps that came from milling....When it arrived instead all swirls I ended up with half of it having the texture of sand.
I wouldn't trust that all of it was copper.
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Tōtōchtin
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Re: Question for welder/metallurgists on Copper

Post by Tōtōchtin »

I know where it came from. lt's 99.9% , just much finer then I can use.
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Re: Question for welder/metallurgists on Copper

Post by cob »

melting it then pouring it in water will give you +- BB's

An old story; stolen gold bars were melted and poured into

bread to make it look like placer nuggets.

I have no proof of that story.
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Re: Question for welder/metallurgists on Copper

Post by RyanAnderson »

cob wrote: Thu Jan 26, 2023 2:37 pm melting it then pouring it in water will give you +- BB's
This. Though use a tall (~ 3ft) piece of pipe, steel trash can, or something with a bit of height, or you'll end up with a birds nest at the bottom of the container. I've done it many times for sling shot ammo with copper, aluminum, and lead, though aluminum doesn't work so well.
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Re: Question for welder/metallurgists on Copper

Post by RyanAnderson »

Also, don't spray molten copper with water. 50/50 chance of sending the copper all over your shop, been there, done that, lol...
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Re: Question for welder/metallurgists on Copper

Post by shadylane »

Tōtōchtin wrote: Thu Jan 26, 2023 9:55 am My question is, if I put it in a pot and use a cutting torch to try to melt it hoping it beads up. Maybe hitting it with a spray to help with the beading.

It will definitely want to bead up.
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Re: Question for welder/metallurgists on Copper

Post by elbono »

Sounds similar to what we called copper mud where I used to work. This was a mix of fine copper powder and the oil/water emulsion that lubricated the process that generated the powder. Nasty stuff because of the lubricant. We paid good money to get 55 gallon drums of the stuff hauled off because it wasn't economical to remelt into usable copper.

Assuming what you have has any moisture and oil removed it will still have high oxide content because there's a lot of surface area to oxidize compared to the mass with small particles.

Molten metal and water has killed or maimed a lot of people. Google "molten metal explosion". If water gets encapsulated in molten metal it turns to steam and blows everything all over the place. Not a real explosion in my book but the result is about the same, hot shit flying around!

You have been warned!

So now to melt it you'll need to put it in a crucible (something to hold it that won't melt). You want to use a reducing flame https://en.m.wikipedia.org/wiki/Oxidizi ... ing_flames (yellow/orange oxygen poor) when you heat the copper it will oxidize if it can find oxygen. A reducing flame absorbs oxygen so a lot of the copper oxide will turn into copper when it loses oxygen. You should end up with a mostly pure chunk of copper if it all goes according to plan. The surface will oxidize unless you shield it from oxygen until it cools, not a big deal probably.
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Re: Question for welder/metallurgists on Copper

Post by contrahead »

Copper melts at 1,984 deg F (or 1,084 deg C) – which is pretty hot. Hotter than the melting point of either gold or silver.

You might want to try fiddling around with a crucible furnace someday. You can make one yourself like I did several years ago, or you can buy one off the shelf..
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The one I made never really got hot enough; mainly because I used charcoal rather than real blacksmiths coal. Air was forced in with a portable hair drier – which worked well enough. Eventually I got distracted and moved on to another project before I ever refined a better fuel delivery system – like a slightly pressurized waste oil drip or simple LP.

Another problem was the crucible. I tried ceramics and steel. The ceramics cracked and the steel would oxidize too quickly and pollute whatever sample that I was trying to melt. What I needed was a decent crucible made of graphite.
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Nowadays you can buy little crucible furnaces online - which wasn't a thing 10 years ago.
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Tōtōchtin
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Re: Question for welder/metallurgists on Copper

Post by Tōtōchtin »

The copper came off a milling machine. I washed of some oil from lubricating the bit. I was worried it would just pool up, when I needed it to bead. I live in an area with few people, going to the local welder is going to raise questions. I just needed to know it would be worth it. I thank you all for your advice.
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Re: Question for welder/metallurgists on Copper

Post by elbono »

It MIGHT make beads but I think it will pool into one big glob which would be pretty cool anyway.
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Re: Question for welder/metallurgists on Copper

Post by Tōtōchtin »

I am trying to make more surface area so I can hang it in a thumper. There is a lot of surface area in half of my copper as it is real fine. To fine for water to flow through easily. I figure when running rum or fruits in the thumper this would help.
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