Getting pennies ready for smelting/melting one day?

[Ecotic]

Hey guys, so I'm about to order a $600 small metal melting furnace. Not to melt down my copper cents (at least not right now while it's illegal), but because I can freely melt down the Canadians I have (or get cheaply on eBay) and I'm also getting into melting detecting and want to be able to melt down the stuff I find.

Well anyway, I've really been doing my homework on melting down metal and I just realized that most guides I read say to clean the metal before melting or else the residual dirt and sticky grime can cause a fire in the furnace. So does this mean I have to go through my entire penny hoard and clean all the grime off the pennies before I can ever safely melt them one day? I mean ugh, that's potentially one hell of a task. The only real fast way I can think of would be to dump my penny hoard in the bathtub, fill it with water, and then dump in 3 bottles of cleaner or whatever chemical works best, and hope the dirt and grime just repels off or floats to the top of the water.

[natsb88]

I would advise against melting pennies in any kind of small furnace like that. You will be melting brass, which gives off zinc oxide fumes, something you most definitely don't want to breathe. You will be running at the maximum temperature the furnace is capable of all the time, which means you'll wear the (expensive) heating element out quickly. And when you're done melting and pouring, you will still just have a block of 98% copper (melting does not refine the alloy), but you'll have to get an assay done to prove it because it is no longer a recognizable form.

Cleaner material in will mean cleaner material out. Dirt will usually float to the top and create a layer of dross. If you are careful, you can pour the metal out from under the layer of dross and let it ride to the bottom, but then you'll have a layer of impurities that will tend to stick to the bottom and sides of the crucible.

There really isn't any money to be made in a home-brew penny melting operation. You can sell Canadian copper here all day long for $3/pound, you probably won't get much more for homemade blocks at the scrap yard. Then factor in your time, the cost of the furnace, electricity, consumables like heating elements and crucibles, molds, etc. Sans melt ban, I think yards will buy pennies for around #2 price and sell them to brass mills who will melt a pot and add more zinc to suit.

[johnbrickner]

Love the good information you disseminate Nate!

[Ecotic]

Thanks for the info Nate, though I wish you had better news. I'm just curious, how long do consumables like crucibles and heating elements last? I'm not entirely sure why crucibles are consumables actually. Impurities stick to the sides and gradually clog it until it's useless? And the heating elements, those are heating wires that gradually burn up or something like a lightbulb filament?

[natsb88]

Thanks for the info Nate, though I wish you had better news. I'm just curious, how long do consumables like crucibles and heating elements last? I'm not entirely sure why crucibles are consumables actually. Impurities stick to the sides and gradually clog it until it's useless? And the heating elements, those are heating wires that gradually burn up or something like a lightbulb filament?

Crucibles will degrade over time from heat cycling and oxygen exposure. Not so much at lower temperatures, but with copper you'd be running it at 2000+ degrees, glowing orange. Graphite oxidizes at those temperatures, essentially eating away at any surface exposed to air. Some photos and explanation here:

http://reviews.ebay.com/Graphite-Oxidat ... 0002145840

You will probably get some erosion on the inside over time from pouring too. Way too many variables to slap a number on the crucible life. Depends on the temperature, how much exposure there is to oxygen (how long it is out of the furnace for pouring), the density/quality of the graphite, etc. It will weaken over time, so even though it may still look usable, you need to keep an eye out for soft or thin spots. The last thing you want is for a load of molten metal to leak into the furnace, or for a crucible to collapse when you're trying to pour. Not particularly likely scenarios, but very bad if they do happen.

The heating element is a high-resistance metal that heats up when electricity is applied, not unlike the wires in a toaster. Except these get a lot hotter . They can burn out like a light bulb filament, and they can also change properties with repeated heat cycling to where they won't get as hot as they did when new. Most of the smaller furnaces have a 2050 or 2100 degree maximum temperature. Copper's melting point is 1984, so it only takes a 5% loss in performance and you're out of luck. Brass alloys melt at a lower temperature, but still hot. The heating element on most of the smaller electric furnaces is embedded in the refractory, so you actually replace the whole inner lining. That can be an expensive part to buy, and some of the cheaper furnaces aren't designed with replacement in mind, so do some research on the availability and price of replacement heating elements before you decide on a furnace.

[DirtyFingers]

You can sell Canadian copper here all day long for $3/pound

No kidding....scrapyards in your area accept Canadian coppers? Guess I need to give my local scrapyards
a call.

[natsb88]

You can sell Canadian copper here all day long for $3/pound

No kidding....scrapyards in your area accept Canadian coppers? Guess I need to give my local scrapyards
a call.

I meant on Realcent.

[DirtyFingers]

You can sell Canadian copper here all day long for $3/pound

No kidding....scrapyards in your area accept Canadian coppers? Guess I need to give my local scrapyards
a call.

I meant on Realcent.

Oh ok duh at me

I got all excited about nothing....sorry about that.

[SilverDragon72]

I would advise against melting pennies in any kind of small furnace like that. You will be melting brass, which gives off zinc oxide fumes, something you most definitely don't want to breathe. You will be running at the maximum temperature the furnace is capable of all the time, which means you'll wear the (expensive) heating element out quickly. And when you're done melting and pouring, you will still just have a block of 98% copper (melting does not refine the alloy), but you'll have to get an assay done to prove it because it is no longer a recognizable form.

Cleaner material in will mean cleaner material out. Dirt will usually float to the top and create a layer of dross. If you are careful, you can pour the metal out from under the layer of dross and let it ride to the bottom, but then you'll have a layer of impurities that will tend to stick to the bottom and sides of the crucible.

There really isn't any money to be made in a home-brew penny melting operation. You can sell Canadian copper here all day long for $3/pound, you probably won't get much more for homemade blocks at the scrap yard. Then factor in your time, the cost of the furnace, electricity, consumables like heating elements and crucibles, molds, etc. Sans melt ban, I think yards will buy pennies for around #2 price and sell them to brass mills who will melt a pot and add more zinc to suit.

How did you get so smart??

[HoardCopperByTheTon]

I would advise against melting pennies in any kind of small furnace like that. You will be melting brass, which gives off zinc oxide fumes, something you most definitely don't want to breathe. You will be running at the maximum temperature the furnace is capable of all the time, which means you'll wear the (expensive) heating element out quickly. And when you're done melting and pouring, you will still just have a block of 98% copper (melting does not refine the alloy), but you'll have to get an assay done to prove it because it is no longer a recognizable form.

Cleaner material in will mean cleaner material out. Dirt will usually float to the top and create a layer of dross. If you are careful, you can pour the metal out from under the layer of dross and let it ride to the bottom, but then you'll have a layer of impurities that will tend to stick to the bottom and sides of the crucible.

There really isn't any money to be made in a home-brew penny melting operation. You can sell Canadian copper here all day long for $3/pound, you probably won't get much more for homemade blocks at the scrap yard. Then factor in your time, the cost of the furnace, electricity, consumables like heating elements and crucibles, molds, etc. Sans melt ban, I think yards will buy pennies for around #2 price and sell them to brass mills who will melt a pot and add more zinc to suit.

How did you get so smart??

I heard a rumor that he goes to school.

[Ecotic]

So what I've learned from this thread is I'll need to buy a gas mask and a bigger, more durable furnace. Well, I guess that's doable.

[mbailey1234]

I wonder what would happen if you ran them through a shot blaster first. I know a guy who has one I may take him 10# and give it a try just for fun. Would it be beneficial to clean the crud off of them before melting?

[frugi]

get a rock tumbler...(even a really cheap small one would work). for less than $100.00, you could get a tumbler that would hold at least 5000 cents. Turn it on, and tumble them with BB's, sand and water....for a few days, checking ever so often to see effect. I have had one this size for 25 years. I tumble anything.

[Rodebaugh]

right on frugi.

Love this video:

[frugi]

I love that video & the background music! very cool!

[scyther]

Great video.

[ScottyTX]

LOL, nice video doc reminds me of my redneck uncle... God bless his soul! He used to live in a bus and make breakfast at one point with a clothes Iron

[Numis Pam]

Interesting video..