Melting Furnace

[kurtak]

IMO & for what it is worth - one of the best investments you (you being anyone) that is going to get into the hobby/business of recovery &/or refining of PMs is to buy a (or make your own) propane fired furnace --- like the one justincase provided a pic of

Besides melting - a propane fired furnace can also be used for smelting & incineration/pyrolizing - AND - they will give you MANY years of service (& cupelling if you do lead collector smelts)

If you are going to do any smelting or incineration/pyrolizing you want one that will hold "at least" a #10 crucible

I have two propane furnaces - one that holds a #4 crucible used mostly for melting (though I have done small smelts in it) and one that holds a #40 crucible used mostly for smelting & incineration (and large melts)

For the dollars invested - those two furnaces were the single best investment I ever made & allowed me to step up my recovery/refining game from a hobby to a money making business

IMO - those bench top electric furnaces are a waste of money (& yes - when I first started I had one)

They are good for one thing & one thing only & that is for melting silver (or lower melt temp metals) in

They don't get hot enough to melt gold or coper in (at least not well) & you can not do any smelting in them

Smelting in them will destroy both the crucibles & the heating elements in them in very short order !!!

Likewise with trying to incinerate/pyrolizing in them due to the acidic gases/fumes produced in the incineration/pyrolizing process

IMO (& speaking from experience) you are WAY ahead of the ball game by spending a few dollars more for a propane furnace - as they will do more work for you & do so for a much longer time (years)

For what it is worth (IMO)

Kurt

 

[kurtak]

https://www.amazon.in/Ashirwad-Ente...&hvtargid=pla-1003724951668&psc=1&ext_vrnc=hi
Holy crap - $7,000 for a (electric) furnace that will only melt 1kg metal

I (you) can buy a propane furnace (10kg crucible) for $400

https://devil-forge.com/gas-furnaces/87-gas-metal-melting-furnace-fb2mb-10kg-full-set.html
Kurt

 

[orvi]

https://www.amazon.in/Ashirwad-Ente...&hvtargid=pla-1003724951668&psc=1&ext_vrnc=hi
Holy crap - $7,000 for a (electric) furnace that will only melt 1kg metal

I (you) can buy a propane furnace (10kg crucible) for $400

https://devil-forge.com/gas-furnaces/87-gas-metal-melting-furnace-fb2mb-10kg-full-set.html
Kurt

Or you can buy induction furnance from China - Aliexpress. For ca 1500 USD you can get one which will provide 7kW of power (rated for 15, but 7-8 is real limit due to frequencies, coil efficiencies, overall eff... etc ). Maybe a bit expensive toy for startup, but once you experience the comfort of the induction, you are never going back Very efficient in heat transfer, very very quick, convenient, easily regulated... Perfect tool for mid-grade equipped refining shop. Of course, we have 35kW variant, that can run from 3000-5000 USD, but is more convenient because of 3 phase plug - and you can do practically whatever you want with it... Smelting 10 kg of incinerated board trimmings in few dozen minutes past 1350°C... Efficiently you can heat 5 gallon crucible with it to do convenient smelts past 100kg of material.

Consider also this option it is well worth the money if you want to stand up from propane a little bit, sometimes you need to conveniently smelt the PGMs etc... I didn´t trusted the thing from beginning (as it originate in China), but we have two and never had bad experience with them, they work well for like 4 years... And we "abuse" them quite a bit One transformer needed to be repaired after we baked it a little completely our fault.

 

[GoIdman]

Do you think this Melting Furnace will work for a few years? If I get a lot of Sterling Silver or maybe Gold I might get one.

https://www.ebay.com/itm/1-3-KG-Gol...962242&hash=item1cee86d64f:g:s~YAAOSw7HFfDsbA

If you insist on electric furnace, try to find a used Calcination furnace sold for dental labs. It gets up to 1300 C, it is closed system, My furnace is on rebuild right now (for some time actually, but i didnt have time to rebuild it with the new heating element and controller). It lasts forever if you use it correctly, it has a kanthal heating wire, by upgrade you can change the heating wire from 1,5kw to 2,5-3kW which will last even more.


I have to agree with fellow members, the best investment is a gas operated furnace.

Be safe,

Pete

 

[Thomacus]

It would be nice but all your home hobbest In the USA do not have 3 phase power at home

 

[Thomacus]

It would be nice but all your home hobbest In the USA do not have 3 phase power at home

you can use a transformer with about 50 amp braker

 

[4metals]

Since the price has gone up a bit for melt considerations, consider this. A small assay furnace. If you read Chapman’s book called How to Smelt your Gold and Silver he discusses using electric assay furnaces for melting. (Great book and in simple common English for the non technical refiners.) I’ve used Vcella Kilns assay furnaces for over 30 years and they are as close to bullet-proof as you can get. And parts are available and they are easy to rebuild.

Why an assay furnace? Well it gets hot enough to melt gold and silver and they are quiet (my only complaint with a gas furnace is they are not quiet). But a small refiner starting out needs an ability to know the value of what he or she is refining. Fire assaying is key to that and this furnace is made for that and at the same time it can do crucible melts in small crucibles. So two birds one stone.

The smallest furnace is a 6” cube inside and they get much larger. (The smallest is about $1400 in 2022) The biggest unit you would want to stand in front of to work is a #13. Bigger than that and you need a full heat suit and hood just to stand there for a second to load it.

I have clients who are big refiners and do a lot of chemical stone removal. The problem they have is is the lots here in the US can be quite small with lots often being a kilo incoming. One way to piss off a manager of a melt shop who is set up to melt huge bars all day is bring him a 15 ounce fine gold lot to melt. One way I have shown many to get around this is to have a small assay furnace in the refining lab and when they get a small melt it’s perfect. The refining shop gets to hand in a melted fine gold bar separate from any undissolved which is easily melted even if it is a fraction of an ounce. And they don’t interrupt the melt shop with lots that are inconveniently small.

An assay furnace can be quite versatile in a start up refinery. I would likely choose it over a gas furnace to start. But soon thereafter followed by a gas pot melt furnace.

I would like to see some brochures or a website from the $1500 induction furnaces from China though, out of curiosity.

 

[Vossmor]

https://www.amazon.in/Ashirwad-Ente...&hvtargid=pla-1003724951668&psc=1&ext_vrnc=hi
Holy crap - $7,000 for a (electric) furnace that will only melt 1kg metal

I (you) can buy a propane furnace (10kg crucible) for $400

https://devil-forge.com/gas-furnaces/87-gas-metal-melting-furnace-fb2mb-10kg-full-set.html
Kurt

That price was in India rupee, or about $90USD. Shipping cost unknown.

 

[4metals]

Despite the fact that the type of furnace Ashirwad makes rarely holds up to repeated melts, the crucible size is quite small. They usually rate these things by the weight of fine gold they hold when filled to the top. A1 kg crucible is quite small, picture a 1" diameter dowel about 3" long. And if you are melting silver it's more like 1/2 kg, same for 10K scrap.

Refining, on any level, presents equipment with vigorous and difficult conditions which takes its toll on furnaces, hot plates, stirrers, glassware...... (the list can go on). If you can, buy things that 1, you can repair, and 2, have a good reputation for longevity.

 

[snoman701]

The small chinese induction melters work. I have one. Takes 3-5 minutes to melt a lb of gold. That's start to finish. Hardest thing about them is finding quality crucibles.

I also have the vcella, though I need to replace my heating elements right now.

 

[4metals]

The small chinese induction melters work. I have one. Takes 3-5 minutes to melt a lb of gold. That's start to finish. Hardest thing about them is finding quality crucibles.

What brand of Chinese induction did you buy and are you still satisfied 2+ years out? I have found that they work great, until they don't. Getting them repaired can be difficult.

 

[snoman701]

I'm not sure what brand it is. It's just a chinese one. They are all pretty much the same after you get inside. It is still working, or at least last time I used it. I was told that the caps can blow up on occasion, but there was no support available in the replacement...it was just the user reverse engineering the circuit, replacing the component and fixing it, or not fixing it.

 

[4metals]

I'm not sure what brand it is. It's just a chinese one. They are all pretty much the same after you get inside. It is still working, or at least last time I used it. I was told that the caps can blow up on occasion, but there was no support available in the replacement...it was just the user reverse engineering the circuit, replacing the component and fixing it, or not fixing it.

Not a stellar recommendation! But also not the first time I’ve heard similar.

 

[snoman701]

They are pretty popular amongst the blacksmiths. I'd consider them hobbiest grade. The volume metal you can melt is awkward. It just a tad more than I can melt with the torch, so what's the point.

I prefer my little propane furnace.

 

[4metals]

A torch and a gas fired furnace served me well for many years refining commercially, mostly for Gold and Silver. That was before induction came on the scene but still, the cost of going induction for a small shop can be substantial.

 

[Xing]

What brand of Chinese induction did you buy and are you still satisfied 2+ years out? I have found that they work great, until they don't. Getting them repaired can be difficult.

what kinds of the furnace would you like, i can look for different brand in China, many company use the small induction furnace.

 

[Xing]

I'm not sure what brand it is. It's just a chinese one. They are all pretty much the same after you get inside. It is still working, or at least last time I used it. I was told that the caps can blow up on occasion, but there was no support available in the replacement...it was just the user reverse engineering the circuit, replacing the component and fixing it, or not fixing it.

do you have photo, i could check the setting. sometimes, change the parts it will work.

 

[snoman701]

A torch and a gas fired furnace served me well for many years refining commercially, mostly for Gold and Silver. That was before induction came on the scene but still, the cost of going induction for a small shop can be substantial.

They are pretty versatile, meaning torch/gas fired. I can do a lot of stuff with fire that I can't do with electromagnetic fields.

Plus, when you are dealing in cement or sponge, you have something with a very poor packing efficiency. Maximum melt on the little induction units is dictated by crucible size. Your maximum crucible size for silver is going to limit you to around a pound or two of granulated silver, but only a couple hundred grams of sponge. It's a royal pain in the butt.

I use my induction melter for heating steel more than I do melting.

If I were a melt shop, it would be a necessity, but at that point, so would a CEIA Induction unit.

But I've come to accept that I don't have the $$ to service a melt shop, and I don't want to use someone else's money. I'm much better off just doing what I do, which is a bit of everything.