Shopping for an induction furnace

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fasTTcar

Well-known member
Joined
Apr 5, 2009
Messages
80
Location
Ontario
Hi All.

I currently am using a RDO bench top easy melt system. I have been having some issues with it recently with keeping the heat high enough when melting over approx. 500 grams of mixed karat gold (usually about 12k). It is viscous and homogeneous but more often than not unable to be hot enough to pop the vacuum pin tube and it just melts it instead.

I have been in touch with the company and they are suspecting it is a software issue and believe it can be solved. I would need to send it back in for maintenance and thinking about my back up plan to continue to melt and assay (without resorting to my little electric job).

One consideration is that it might be time to upgrade to a larger unit for master melts and possible silver processing and keep the original unit for day to day usage.

I have 3 phase electrical available, so that is not an issue. I need something that has a smaller footprint and can handle 5 - 10 kg lots. A tilt system would be preferred, but I am under the impression they are a big jump in price.

Currently looking at the RDO 10kg and a few others.

Any tips or suggestions would be appreciated.

Thanks,
Daniel
 
Daniel,

I currently use a propane furnace for melts up to 5kg. Have you considered using one ? It's is very efficient generates a lot of heat.

I built mine myself and it cost me only a couple of hundreds. If you ever come by Sherbrooke, I'll show you how it performs ;)
 
Mike at Toronto surplus has about 40 of them. I think he quoted me $5000. http://www.torontosurplus.com/
 
glondor said:
Mike at Toronto surplus has about 40 of them. I think he quoted me $5000. http://www.torontosurplus.com/

Thanks for that. It looks like a power supply, not the furnace though.

I am not a hardware guy, but I don't believe that is what I need.
 
Daniel,

I have had the same exact problem and I found that I had the metal too hot and it just melts the whole end of the pin sample rod. Turn the heat down a little and I bet it solves your problem. I do business with RDO also and know them to good people. I have a small Wand Melter from another supplier and went thru the same problem. I like not having to try to handle the crucibles with thongs. I have found several Chinese melters that tilt but are overkill for my needs.

Turning down the heat solved the problem for me and I hope it works for you.

Dan
 
I will give it a shot, but it seems that it is lack of heat that is the problem.

Heavy crucible loads tend to be less viscous and cool quicker when pouring.

Maybe my next melt I will dial the power back to 80% when sampling and back up to 100% when pouring. See how that works.

Thanks for the tip Dan. Also, if you want to shoot me the name of some of the tilt and pour furnaces, I would be interested in checking them out.
 
Daniel,

Most of the cheap ones I have found are from Google searches and they are in China. Another small suggestion, preheat the crucible until it starts to turn a dull orange before dropping in all the metal. Then drop in 40-50 grams and let that get melted and feed it in 40-50 gr lots. It actually goes a lot quicker and when it is when it's all melter, stir it and take the pin sample. I can't run my machine at 100% as it get too hot and shuts off. I try to run mine at 83%-85% and feed it. Usually takes me about 2-3 minutes to melt 500 grams.

Another tip. Try pouring into a tilting ingot form at an angle. Now this promotes solidification and pushes the high & low limits of the bar. I take 7 XRF readings with one on each short side and two on the long sides, average them, and I am within $20 of what NTR pays me. On my last 50 cashouts, it's almost always dead on!

Dan
 
I do preheat the crucible and slowly add material to it.

I do not assay the bar, as that is what the pin sample is for.

My last 3 settlements with the Royal Canadian Mint were within a 10th of a gram on 100 + ounce lots.
 
Great,

With 100 Oz bars, you need the bigger melter. I cash out 2-3 times a week and certainly a much smaller fish. all the cheap melters I am finding are (of course) out of China. Here is the Google Search http://www.alibaba.com/trade/search?SearchText=induction+melter&IndexArea=product_en&fsb=y . I have a very tough time buying things without service. I have been seaching for a large one in 50 lb to 100 lb area for another industry that has lots of Aluminum and high chrome steels. I know RDO has a couple of tilt melters. I might have a buyer for your old machine. Just have Bob give me a call with a price and trade it back in for one of his larger machines.

Dan
 
Currently, I am shipping 500 gram to 1 kilo bars to the mint. They are re melting them anyway, so it really does not matter. I just would like the flexibility to handle larger bars and melt and assay silver, which is impractical with my current setup.

I am planning on keeping the smaller bench top for now. At the very least as a back up, but it will still be handy for the dealer lots that I have coming in.
 
Ended up giving Bob at RDO some business.

Purchased a 10kw benchtop induction furnace capable of melting 10kg's of gold / 7 kg of silver. Had the electrician in today working on the hookups (requires 220 3 phase). Hope to get a fume/smoke hood setup next week and hope to be going at full speed by mid January.

I am excited to be able to start melting silver, as it has been impractical for the volumes that I generate in the small furnaces that I currently have. I can get a much better handle on what I am shipping out and hopefully be able to be much more aggressive on buying at a wholesale level.

Once this is all put to bed, I am very anxious to start aggressively courting the wholesale business in South Western Ontario. I figure there is a big market here for jewellers and pawn shops that are sick of counting their fingers after shaking hands with many of the Toronto melters.
 
RDO are good people! Let me know how the new melter is working out for you. My little Wand Melter is really a workhorse and trying to get them to make a bigger one!

Dan
 
fasTTcar said:
Ended up giving Bob at RDO some business.

Purchased a 10kw benchtop induction furnace capable of melting 10kg's of gold / 7 kg of silver. Had the electrician in today working on the hookups (requires 220 3 phase). Hope to get a fume/smoke hood setup next week and hope to be going at full speed by mid January.

I am excited to be able to start melting silver, as it has been impractical for the volumes that I generate in the small furnaces that I currently have. I can get a much better handle on what I am shipping out and hopefully be able to be much more aggressive on buying at a wholesale level.

Once this is all put to bed, I am very anxious to start aggressively courting the wholesale business in South Western Ontario. I figure there is a big market here for jewellers and pawn shops that are sick of counting their fingers after shaking hands with many of the Toronto melters.


Noticed you have some induction loads and also adding this one, just wondering about the power factor . In US they will charge a power-factor penalty if it's too low.

just curious ,..
 
scrappile said:
Noticed you have some induction loads and also adding this one, just wondering about the power factor . In US they will charge a power-factor penalty if it's too low.

just curious ,..

Don't believe that it will be an issue. I am in an industrial mall and have not seen any major changes in my power bills.
 
fasTTcar said:
scrappile said:
Noticed you have some induction loads and also adding this one, just wondering about the power factor . In US they will charge a power-factor penalty if it's too low.

just curious ,..

Don't believe that it will be an issue. I am in an industrial mall and have not seen any major changes in my power bills.


just thought if it was low,
The use of synchronous motors is another method of providing power factor ... could possibly use one for the fan for fume hood, since it would be running most of the time,..??

,Rremembered doing the formulas in class . Thanks for checking
 
Melt shop.jpgWell, I am finally up and going. Have the room built, the venting operational and the new furnace hooked up and cooking.
 

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Nice size machine! Thanks for posting! Do you use a Crock Pot with Pickle to quick cool your bar and remove scale?

I fried my coil in my wand melter with trying to do powder with Pd in it. Every time I have trouble with an Induction Machine, it's always because of powder. I think I have learned my lesson.

dan
 
Dan Dement said:
Nice size machine! Thanks for posting! Do you use a Crock Pot with Pickle to quick cool your bar and remove scale?

I fried my coil in my wand melter with trying to do powder with Pd in it. Every time I have trouble with an Induction Machine, it's always because of powder. I think I have learned my lesson.

dan

I just drop hot bars in a meatloaf pan with cool water for small melts and in a metal bucket with water for larger bars such as the one pictured.
 
As a suggestion, try a bigger cheap crock pot with a Pickle solution set on medium. Drop out of the mold and put it in the pickle solution. Knocks off 95 of any scale. A rotary brass wire wheel on a cheap Sears grinder will make the bars perfect.
Dan
 
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