# Induction Furnace 30 Kw



## Anonymous

Just the right size for what I have in mind, I need the ability to economically melt brass and bronze, my home made propane fired furnace served me well over the past three years but it's time to move along.

Recently inquired from a Chinese ebayer selling induction furnaces for a single phase unit and he responded with the following information.

This set up is $ 4995. it has 30kw induction heating machine and a tile
system. the capacity is around 10kg.

The video as here:

http://www.youtube.com/watch?v=zVdQimrinjY


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## Noxx

I also wish to purchase an induction furnace. Not 30kw, but enough to melt a few kilos.

I am not sure about the reliability of these units though...


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## Anonymous

Harold would you please go over the specification sheet for these induction furnaces and give us your opinion based on the information provided by the seller.


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## Noxx

I ask for a quote at http://superiorinduction.com/

I'll let you know the price for a 7KW unit.


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## Anonymous

Noxx said:


> I ask for a quote at http://superiorinduction.com/
> 
> I'll let you know the price for a 7KW unit.



Where it gets confusing Knoxx, some induction are LF - Low Frequency, MF Medium Frequency, HF High Frequency, some are designed for heating and annealing, some for soldering and then what we want melting. 

I'm hoping Harold_V will shed some light on the subject if induction furnaces. 

Best Regards
G


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## Noxx

I got the quote. These units are pricey.



> Hi Jean-Nicolas,
> 
> Attached is the quotation to the induction heater. If you do less than 2Kg of gold using a graphite crucible then the 7KW will do fine. Anything larger would require the model 12KW which is 240 volt three phase, but we have been able to actually single phase it.



The 7kW unit is $9990 US.

What we need is HF or MF. Low is used on thick material.


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## Palladium

8)


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## Barren Realms 007

5,000 for a 30KW or 7KW for 10,000. HMMMMMMMM decisions decisions. The 5,000 I might go for the 10,000 I would build myself.


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## Barren Realms 007

gustavus said:


> Harold would you please go over the specification sheet for these induction furnaces and give us your opinion based on the information provided by the seller.



Gustavas, 

I assume you have a 3 phase service for the 30KW unit? Or are you going to use a transformer for your 3rd power leg?

Is your electrical service for your building able to handle another 60 amp load for the 15KW heater or larger load for the 30KW?

I also noticed a caution in the submital that says the head unit does not have a flow switch for the water entering the unit, you might want to consider putting one in to save problems.

I noticed that it has an automatic cut off for over voltage. I don't remember where you are located at but if you have power spikes you might want to put a filter inline on this thing to smooth out the voltage.

Nice looking unit.


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## Anonymous

Three phase at the street, not in my shop. I have a very good supply of waste veggie oil and have been making bio, I would purchase a suitable used diesel generator to supply the power needed for the furnace. This way the generator could be used for a standby if the power ever went down.

Wow what a spread is price, the quote I received is China direct, while the one Noxx got is after the item reached our shores - greed.


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## Barren Realms 007

gustavus said:


> Three phase at the street, not in my shop. I have a very good supply of waste veggie oil and have been making bio, I would purchase a suitable used diesel generator to supply the power needed for the furnace. This way the generator could be used for a standby if the power ever went down.
> 
> Wow what a spread is price, the quote I received is China direct, while the one Noxx got is after the item reached our shores - greed.



You could buy a transformer and put it in to make up your 3rd leg cheaper than purchasing a genrator to handle the load this will require.


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## Anonymous

Barren Realms 007 said:


> gustavus said:
> 
> 
> 
> Three phase at the street, not in my shop. I have a very good supply of waste veggie oil and have been making bio, I would purchase a suitable used diesel generator to supply the power needed for the furnace. This way the generator could be used for a standby if the power ever went down.
> 
> Wow what a spread is price, the quote I received is China direct, while the one Noxx got is after the item reached our shores - greed.
> 
> 
> 
> 
> You could buy a transformer and put it in to make up your 3rd leg cheaper than purchasing a generator to handle the load this will require.
Click to expand...


I don;t understand how this would work, the induction furnace requires Input Voltage 380V/415/480V. Using a transformer with my incoming 220 volt with a transformer for the 3rd leg is not going to work. Otherwise I would have considered using a roto phase which can be made from junk yard parts.

Anyone interested in plans for roto phase I have from simple and economical to build plans to more the more expensive self starting units, too many files to list on the forum.


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## Harold_V

Barren Realms 007 said:


> You could buy a transformer and put it in to make up your 3rd leg cheaper than purchasing a genrator to handle the load this will require.


The third leg doesn't come from a transformer (not a stationary transformer, anyway). It can be developed by spinning a three phase motor, with single phase, however. The generated leg can be somewhat wild in voltage. I had considered a phase converter such as this for my induction furnace prior to making the decision to have three phase run to my shop. That a 75 horse motor was required made having three phase run an easy decision. Unlike the induction power supply offered, mine is a motor/generator unit. 

Gill,
I took a look at the literature, but there's more to this than may be obvious. Frequency of an induction furnace is critical, although it does have a bit of a spread. For instance, if one intends to melt small volumes of gold powder, the frequency required would be significantly higher than if one were to melt an equivalent volume of gold in the solid. Same thing applies to other metals, of course. As the frequency goes higher, even non-conductive items can be heated. 

If I ever find enough time to get all of the information from my old computer installed in this one, I'll be able to provide you a graph that provides guidelines for making a wise decision. Mean time, remember that frequency is tied directly to volume. Huge induction furnaces operate at line frequency (60 Hz), and go upwards from there. My power supply is a 50 KW model, and operates @ 3,000 Hz. They made the identical unit that operated @ 10,000 Hz. It likely would have been a better choice when starting out with a charge of small items. A large item heats faster and easier, and may be required if frequency isn't high enough. 

Sorry I'm not more help. 

Harold


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## jimdoc

Quote from Harold;
"If I ever find enough time to get all of the information from my old computer installed in this one, I'll be able to provide you a graph that provides guidelines for making a wise decision"

Harold,
I have one of these Tornado devices and it works good;
http://www.thetornado.com/backup_files.asp

I got mine for $20 on sale, the $49 price looks like the list price.
Or on Ebay or Newegg, or Tiger it should be cheaper.

Jim


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## Harold_V

Thanks, Jim. I can also buy a cable that permits the same thing. My big problem is lack of time. I am still running Vista, and have W7 at the ready. Had a problem when I attempted to do the install, losing Norton in the process. Had to go back to square one, costing me a full day. I'm trying to avoid transferring anything that isn't necessary until I do the upgrade, which will come, from all indications, about the middle of some year! 

Harold


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## Barren Realms 007

gustavus said:


> I don;t understand how this would work, the induction furnace requires Input Voltage 380V/415/480V. Using a transformer with my incoming 220 volt with a transformer for the 3rd leg is not going to work. Otherwise I would have considered using a roto phase which can be made from junk yard parts.
> 
> Anyone interested in plans for roto phase I have from simple and economical to build plans to more the more expensive self starting units, too many files to list on the forum.



The 380V & 415V are probably used in other countries besides here in US. I have never run across those voltages. 

Here in the US we have 110V/208V/220V/277V/480V. Generaly when you hear someone discussing 220V or 240V they are talking about the same voltage, same thing goes for 440V & 480V. 

You will have what is called a Delt or Y power source at the utility power pole and they step down the voltage according to what your application and needs are. The Delta & Y systems are 2 different power systems, They will not be used together buy the utiliy comapny at the same location generaly.

Unfortunaly I have never had to go from 1 phase to 3 phase for the consumer to use. At least as far as I can remember. My company use to do a lot of commercial and industrial work and installations. But since I have downsized my company I haven't done a lot of this work in the last few years.

Here are a couple of links that might help you out.
http://www.3phasepower.org/3phaseconverters.htm
http://www.usphaseconverterstandards.org/buildyourownphaseconverterplans.htm

The post that Harold made about this was good.


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## jimdoc

Maybe you can add your hard drive as a slave drive on the new machine? I seem to remember you have a use for the old computer
though, that would mess that idea up.
Jim


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## Palladium

One question i haven't heard yet. Does that price include the cooling unit. Most companies sell the unit as a seperate item. Make sure it included.


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## Noxx

mine did not. the cooling unit is $900 more.

i am sure you can build one yourself for much less than that...


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## Refiner232121

I thought there was no benefit in having inducton furnaces.
Harold used a propane furnace and never had induction furnace
I have seen induction furnaces at work and the person who had this machine always used a torch to heat the big bars because the furnace didnt melt it fast.
Maybe I should read this thread more carefully


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## Noxx

Refiner232121 said:


> I thought there was no benefit in having inducton furnaces.



Time is money my friend


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## Harold_V

Refiner232121 said:


> I thought there was no benefit in having inducton furnaces.


You were badly informed. An induction furnace is the finest melting process you can acquire. They're just costly, and generally require a three phase service, aside from small units. 


> Harold used a propane furnace


Nope! I've never used propane, and wouldn't today. I don't like the damned stuff, and it's not cheap, anyway. My furnaces were fueled by natural gas. I had a 1 pound meter at the castle, so some appliances had to have pressure reducers as a result. 



> and never had induction furnace


Ahhh! But I do! 

I have a second generation (motor/generator) Ajax Magnethermic 50 kw induction furnace. Its intended use is for melting steel, for conversion to ductile iron. As I said, induction is the finest possible way to melt metals. Clean, non polluting melting, with no sound and almost no fumes. 



> I have seen induction furnaces at work and the person who had this machine always used a torch to heat the big bars because the furnace didnt melt it fast.


That's due to one of two things. One of them could be that the unit was underpowered. The other could have been that it operated at the wrong frequency. 

With induction melting, power is everything. Given a large enough power supply, cold metal can be melted in but a few minutes. 

During the Viet Nam war, I held a job, briefly, at Tooele Army Depot. We were engaged in a full time rebuilding project of armored personnel carriers. One of the items that were made in the shop was the main shaft for the transmission. It was hardened on site by induction heating. The shaft was inserted in the coil, then power applied. Within 15 seconds, the shaft was at a red heat. Try that with a torch, or ten. 



> Maybe I should read this thread more carefully


And keep an open mind. Some times it's not easy, because some of the people that post here appear to be hell bent on re-inventing the wheel, but if you pick and choose carefully, information from well grounded and rational people, you can learn a great deal here. 

Harold


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## goldsilverpro

I agree with Harold. I much prefer natural gas over propane, for several reasons. Unless you have a large propane tank, the tank will freeze up, the propane will stop flowing, and the furnace will shut down. I've seen 1/4" of ice build up on the tank. At least, you can tell how much propane is left just by looking at where the freeze line is. Also, propane burns too hot for my likes. Changing tanks is a pain. The tank always seems to run out at a critical time. With natural gas, you just hook it up once. I also think natural gas is easier to control. No problems with natural gas.

For general purpose melting and fluxing, a natural gas furnace can't be beat. You can do most anything in a gas furnace, if you've got the time. An induction furnace is much, much faster, but it is more limited. It won't take heavy fluxing. For stuff like karat gold scrap, it is the best. With a big budget, I would have both. With a small budget, I would build a natural gas furnace and use it for everything.


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## jimdoc

goldsilverpro said:


> With a big budget, I would have both. With a small budget, I would build a natural gas furnace and use it for everything.



Ah yes, there is that elusive big budget I wish I had. One of these days I tell you. Jim


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## goldnugget77

I am wondering if it is necessary to have both of these gases or if I buy 
a natural gas tank that will be enough


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## Barren Realms 007

goldnugget77 said:


> I am wondering if it is necessary to have both of these gases or if I buy
> a natural gas tank that will be enough



You can't buy a natural gas tank only propane tank's.


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## goldnugget77

I was thinking about but i was not sure
Then I would have no choice to use propane gas


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## Barren Realms 007

It really depends on what you are wanting to do. Propane is not the only bottled type of gas that can be used.


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## Anonymous

If you use a restiction (expansion valve)to flash the propane from liquid to gas you can use the bottle upside down and it will not freeze.

Jim


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## Anonymous

james122964 said:


> If you use a restriction (expansion valve)to flash the propane from liquid to gas you can use the bottle upside down and it will not freeze.
> 
> Jim




My propane furnace is running a 800,000 btu propane torch on a liquid diet supplied from 500 gallon tank. It works great the only problem is that propane is unjustly priced in comparison to other petroleum products. I can still buy a ton of coal here in Manitoba for $30.00.

An induction furnace would certainly be more convenient, plus I would have the advantage of being able to melt iron, brass and bronze economically.

I have melted copper and brass in my furnace but have iron, some foundry-men claim that they have done iron in their homemade propane fired furnaces. However I take my metal casting seriously and know that propane will not meet the proper melting temperatures required to properly alloy the metals I wish to cast.

Some guys think that you can melt of a bunch of pop and beer cans or computer heat sinks to make a good casting, this is not true. There are hundreds of aluminum alloys and each has a purpose.


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## Noxx

Now it seems that we are three looking for an induction furnace. Any clues where to buy a used one? 

On the other hand, I am not sure I would trust a furnace made in India or China. Yes, they are 1/3 the price of one in North America, but will they last (or even work properly) ?


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## EDI Refining

Noxx- get a adjustable temp oven furnace for your use. So you can melt and do fire assays with the same unit.


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## goldsilverpro

> Noxx- get a adjustable temp oven furnace for your use. So you can melt and do fire assays with the same unit.


I wouldn't agree with that, especially if it was electric. Too limited. Too inconvenient. Unless you're doing nothing but clean stuff, too much maintenance. A little slag running over and you have a big hole in that soft firebrick. Some types of fumes (like if you're in a hurry and don't happen to rinse all the acid out of your gold powder) will eat the elements or make them so brittle that they break when you touch them. You have to remove the crucible to flux or to even look inside it - If you're not fast, the melt will freeze. They're slow. Been there. Done that. Besides fire assaying, for melting anything except pure gold or silver or, maybe, karat gold scrap, I think they are worthless.

With a gas crucible furnace, you can do about anything I can think of, except cupelling. You can do sludges, heavy fluxing, etc., etc. As a refiner, all sorts of things need to be melted.

Were it me, if I were also doing assays, I would have both. If I weren't doing assays, I would never use an electric box furnace in a refinery. It would just sit in the corner and gather dust. However, I would use it for heat treating when I make my carving chisels and knives.

And, of course, I would have a torch setup. To me, a torch is 10 times better for melting pure gold than an electric box furnace. If the quantity was too big for a torch, I would use my handy-dandy gas crucible furnace.

I can only think of two other types of melters - (1) a wonderful induction furnace and (2) one of those high-dollar, slow, crucible eating, worthless, cutesy, Electro-Melt things with a handle on it.


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## Noxx

> I can only think of two other types of melters - (1) a wonderful induction furnace and (2) one of those high-dollar, slow, crucible eating, worthless, cutesy, Electro-Melt things with a handle on it.



Lol, pretty straightforward


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## Harold_V

What Chris said. I can't think of a less useful furnace for the refiner than an electric one, but my comments, previously, fell on deaf ears (or blind eyes). 

There are some things a newbie must learn the hard way. I'm of the opinion that no amount of talking will convince a guy that has a different idea that a good and proper torch is the best possible way to go, assuming one is not assaying. I melted even large lots of gold by torch. It offers very good control, and I never had to flux my gold, so that wasn't an issue. 

If I was refining today, I would have no need for an electric furnace, in spite of the fact I have two of them. Each is targeted for heat treat and burning out waxes for investment casting. I wouldn't consider, even remotely, using either of them for melting gold-----not under any circumstance. 

Harold


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## 4metals

The same company Vcella, that makes assay furnaces makes an electric crucible furnace, the smallest crucible model they make is #16.

http://www.vcella-kilns.com/products.html

They have a long cold start heat up time but once hot they do well on karat and silver melts. They are easily serviceable and I've seen them in use at gold buyers who don't want the expense of induction or the noise of gas. They won't do platinum but for gold and silver this form of electric melting fills a niche.


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## PreciousMexpert

If I used a propane gas instead of natural gas
would this make the gold impure


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## 4metals

No, the only effect is it costs more than natural gas.


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## Anonymous

Noxx said:


> Now it seems that we are three looking for an induction furnace. Any clues where to buy a used one?
> 
> On the other hand, I am not sure I would trust a furnace made in India or China. Yes, they are 1/3 the price of one in North America, but will they last (or even work properly) ?



You got it right Noxx, listen to this youtube video of my metal lathe not even a year old. Sounds like a thrashing machine.

I added oil on receipt of the machine and did an oil change a week ago, opened up the gear case last night and the oil is full of metal particles. The lathe has only made a few light projects from metal otherwise most of my turning has been from hardwoods.

$7000.00 and they never even had to strong arm me for the money.

http://www.youtube.com/watch?v=OxxNH1SbEQ8
http://www.youtube.com/watch?v=3HDkLm05xG4


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## Noxx

There is definitively something wrong with the lathe...

May I suggest that you change the youtube video name, so that everyone could see how bad is this tool.


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## Anonymous

Noxx said:


> There is definitively something wrong with the lathe...
> 
> May I suggest that you change the youtube video name, so that everyone could see how bad is this tool.



Still dealing with warranty, contacted the store where I purchased the lathe several weeks back with out any solution to remedy. The distributor was contacted yesterday morning who asked for a list of parts needed to replace solving the problem.

The list is extensive, because an internal keyway on the cluster gear was cut so sloppy this is the cause of the noise plus excessive wear from the gear has made metal particles which have circulated throughout all the bearings. In addition to the gears and shaft, asking for all new seals, gaskets and bearings.

Because most of my turnings were from hardwoods, using high speed 2000 rpm the noise went undetected, recently I made a small threading die holder and had opportunity to use the lower speeds on the lathe - flabbergasted.


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## Harold_V

My Sag 12 Graziano was purchased new in 1967 and has never experienced anything similar. Early on, within the first year, it had two clutch failures. You may find this hard to believe, but a factory repairman came to my shop and replaced the clutches, on two different occasions. Not a big deal until you consider that the repairman was dispatched from Italy. He spoke no English. 

Considering your comments about metallic particles circulating with the oil, keep in mind that the main headstock bearings are precision (or should be) and very expensive to replace. It is highly unlikely they have escaped damage. I recommend you do a test on the spindle, using a tenth indicator. Also, turn a diameter and check it for roundness. 

The ultimate deal would be if they will accept a return of the machine. 

Good luck, Gill. Keep us posted on the outcome. 

Harold


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