# Table Top Electric Furnace 110v



## kadriver (Oct 31, 2017)

I would like to add a small electric furnace for incinerating jeweler's bobbing compound, and jeweler's filings and clippings, and calcining. Does anyone have any experience with an electric furnace, either good or bad?

Thank you! kadriver


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## Topher_osAUrus (Nov 1, 2017)

Electric furnaces are belittled all over the forum. They just cant compete with a good gas furnace.

Pretty sure a guy has had one up for sale in the classified section here for over a year..


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## nickvc (Nov 1, 2017)

Depending on the make up of jewellers bench waste makes a huge difference on how to treat it, if it has carborundum in its not easy to get a good melt result and incineration and wet refining is the way to go, if it’s a setters bench sweep then melt and assay are usually an easy option same as bench filings but that is based on having access to cheap quick asssays. If you have to refine direct from the bench sweeps its a journey of faith and trust with you and your customer, they only work on 18k and the odd bit of lower karat and silver so why isn’t my sweep result based almost entirely on 18k prices, been there and done that which is why when I was refining full time most lemels and bench sweeps were a melt and assay job, the melt done while either the customer watched or waited for their bar.
We deal with people who know that the general rule is rob the customer if they can’t prove it, so been honest with them is a hard ride, they assume everyone is a crook and even an honest report of values is questioned but in time most learn that you are trustworthy but explaining why you charge what you do against bogus claims of returns can be frustrating to say the least.


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## kadriver (Nov 1, 2017)

I only have one customer to deal with, and he is my boss! I work at his jewelry repair business. He has taught me how to set diamonds with a graving tool. Also how to size gold and silver rings, up or down. The bench sweeps are from his drawer. He keeps it open under his bench block. He is constantly sawing gold and platinum rings all day long. He does ring sizings while you wait in 20 or 30 minutes in most cases. As a result he always has a line of customers out the door. So the gold dust builds up fast. 

I did a section of carpet from under his work bench about 1.2 foot square. I got about 24 grams of pure gold from that.

It would be nice to have the convenience of a small electric furnace, vented into, and sitting right next to, my fume hood. I envision just putting the material into the furnace set on 600 or 800 degrees F in a fused silica melt dish and just let the heat do the incineration for me.

He's got a ton of material saved up for me to do now that I'm back in business. I normally do all his scrap. We tried sending a pound of bobbing compound in to an un-named big refiner and they tried to melt it to get an assay. The regular guy was on vacation. Of course it came back way low. Based on my past yields with this material, I told my boss to expect 22 to 26 grams of pure gold for the pound of bobbing compound valued at around $1000 - but when we received the settlement they only gave us $268! We complained and they graciously did an investigation and made things right. What a relief.

Anyway, I'd still like to hear from anyone who has an electric furnace with any results good or bad.

I'll check the for-sale section on the forum for the item mentioned in the post above.

Thank you, kadriver


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## kadriver (Nov 1, 2017)

Nick, the bench material will have much carborundum because he uses little carborundum wheels to grind the gold when sizing rings or when doing other jewelry repairs. I remember the first time I saw it in the refining waste. It looked like something valuable and I kept adding nitric to the AR to get it to dissolve and it never did. I brought it in to the jeweler and he said, "that's carborundum". Lesson learned.


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## cuchugold (Nov 1, 2017)

https://www.kanthal.com/en/products

There you go. They tell you how to make one yourself for cents on the dollar. Very simple. The heating element oxidizes somewhat fast, unless you control the oxigen inside the furnace.

I remember your fine refining videos and photos... 8)


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## kadriver (Nov 1, 2017)

cuchugold said:


> https://www.kanthal.com/en/products
> 
> There you go. They tell you how to make one yourself for cents on the dollar. Very simple. The heating element oxidize somewhat fast, unless you control the oxigen inside the furnace.
> 
> I remember your fine refining videos and photos... 8)



Do you have one of these? How has your experience been with it? Thank you.


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## cuchugold (Nov 1, 2017)

In 1988 I built a electric furnace for an AP Green size 14 crucible to refine with the Miller process. The chlorine never got close to the heating element. It worked fine, and reached melting temperature in 10 minutes.

My current was 3 phase 220 V, not 1 phase 110 V.

Try to keep the fumes from your incinerator away from the heating element. That's all.


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## kadriver (Nov 1, 2017)

i found the electric melt furnace in the for sale section.

I've got one of those and it works great for melting cement silver for my silver cell.

But what I'm looking for is a furnace with a door on it with a small vent hole in the top.

It may be called a "burn out" or "dental" furnace.

I'm not going to use it to melt metal, just to incinerate the waste that I want to process.

Any experience with one of these would be helpful. Thank you, kadriver


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## snoman701 (Nov 1, 2017)

Incinerating in an electric furnace isn't advised without doing it in a chamber that is sealed from the elements.

kanthal or nichrome wire builds an oxidation, if you create a lot of sooty smoke, you run a risk of creating a reducing environment. This oxidation is self limiting, but if you change the environment to reducing, you will reduce the oxidation and it will flake off, then the element will oxidize again, and reduce, and oxidize and so on. This greatly reduces your element life.

There are ways around it. 

Personally, I've got a small stainless chamber that I can put in a kiln. I then have a stainless flexi hose like you'd use for your gas line hookup. This vents the smoke outside of the kiln. Once it is done pyrolizing off the volatiles, you just open the chamber and let it oxidize everything. 

I'd much rather just have a gas incinerator.


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## snoman701 (Nov 1, 2017)

Your burnout furnace is just that...it's where you put investment (the dried plaster that jewelers pour gold / silver in to). Anyway, it's a mould because it has a small piece of wax inside shaped like the object you aer about cast. Then theres a "sprue" that goes to the base, which is a little cone. All of this wax is put in the furnace, first to set the investment, then to burn the wax out in it's entirety, finally, to preheat the mould.

There's really nothing to them...so just buy one you like the looks of and fits the budget. Keep the book. Order replacement elements from Euclid Kiln Elements as you need them (realistically, not often)

You'll also find that the best way to clean dirty glassware is a quick anneal cycle. You basically just heat it up til just before it's going to collapse, then let it cool really really slow. No concerns of making silver chloride!!


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## kadriver (Nov 1, 2017)

That all makes good sense, thank you for the insight.


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## nickvc (Nov 2, 2017)

I used an old wax burnout furnace for doing floor sweeps and it worked well for incineration but it did create a lot of smoke,if you could return the smoke to burn I’m sure that problem would be solved, I used steel tote trays with a lid fashioned to loosely fit the top to contain the material and slowly raised the temperature and allowed the material to sit at high temperature for around an hour.
For bench sweeps you might find using a Corning Ware vessel and a torch under an extractor might be the easiest and fastest approach not to mention the cheapest.


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## kadriver (Nov 2, 2017)

An old burnout furnace sounds good. I only do this several times a year, not daily. I would have it sitting just below my exhaust hood to draw off the smoke. I've used a torch and corningware dish and it works. But I always seem to blow some of the material out of the dish.


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## snoman701 (Nov 2, 2017)

An old toaster oven is dirt cheap and will get plenty hot enough I'd think.


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## Shark (Nov 2, 2017)

snoman701 said:


> An old toaster oven is dirt cheap and will get plenty hot enough I'd think.
> 
> 
> Sent from my iPhone using Tapatalk



Most toaster ovens come without insulation. I packed mine with Kaowool, and it holds heat a lot better now.


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## kadriver (Nov 2, 2017)

Shark said:


> snoman701 said:
> 
> 
> > An old toaster oven is dirt cheap and will get plenty hot enough I'd think.
> ...



This is perfect, I can find one at a yardsale sale for a few dollars.


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## snoman701 (Nov 3, 2017)

After thinking about it, they may have a snap disc thermostat in them that you have to bypass. It will shut down the oven if it reaches a high enough temp. At the same time, just the regular operating temp may be plenty hot enough. I know it can turn toast black, I've just never left it long enough to see if it will turn it white afterward!


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