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Induction forges

Chris Cramer

Super User
Vendor
Premium Member
I see. I’ll make a video of my build if it works fine, so every one can feel more confident purchasing the unit. I’ve looked at some commercial units online that look pretty similar to a welder and plasma cutter. I’m a bit curious about how it would work for someone to use an old welder as a power source with good control of the amperage, and voltage, as long as the other components within the driver are strong enough to make the unit operational. High alternating current runs back and forth through the coil and generates an alternating magnetic field which creates the heat by induction. as soon as anything magnetic or conductive passes through the magnetic field then the cells within the metal continuously move back and forth creating heat by friction or high current. With that, a graphite crucible that fits through the coil is used to melt metal like copper brass, platinum, silver, and gold. That would be very useful for casting metal.
 

kevin.decelles

Jack of all trades -- Master of none
Premium Member
Thx Chris, From the pictures, the coil loop looks to be in the 2-3 inch diameter, not a 5-10 inch diameter that I'd expect for a crucible. Were you envisioning a different coil?
 

Chris Cramer

Super User
Vendor
Premium Member
I keep getting put off by the plumbing/water cooling requirements. The power consumption seems reasonable, and would actually be pretty good off my solar here in the fire season, when the neighbors are least happy with my solid fuel forges. But I keep imagining all sorts of "water everywhere" grief in my future with one of these.
I’ll have to find a good way to seal the mini water hose, but even if a small leak does happen, it is only a very small quantity of water moved by the mini water pump. Commercial induction heaters pump cooled water through the coil from a small reservoir, that is cooled continuously to get rid of the heat. I’ll have to add that to my design as well, probably with ice if that could last long enough.
 

Chris Cramer

Super User
Vendor
Premium Member
According to the information on Amazon the coil is 50mm. I don’t know if that refers to the inner or outer diameter, but the crucibles I ordered are 50mm as well and different heights. If they don’t fit then I could either widen them or make another one with some copper tube.
 

Chris Cramer

Super User
Vendor
Premium Member
I've been trying to convince my Boss to buy one for years. We harden a lot of O1 fixture gauge pins a year, and currently just use oxy/acetylene torch. An induction forge would be awesome for our process, and the ROI would be pretty quick.

I have one of the little 1000w ones from banggood, and it will actually bring stuff up to 1/4" to a dull red. I haven't played with it much, but I'm sure with some different coil shapes I could find some good uses for it. I just bought it as a toy to play with. Would love to get one of those big ones at home eventually, but have a much longer list of stuff I want first. I've been tempted to buy one of the 2500w ones but I'd rather just hold out for the big guy.
How much voltage have you tried using it with? The more voltage the more current and power is generated. Several people have used the 1000W modules with a 48V power supply and are able to heat items as thick as 1”.
 

Dan Dubeau

Ultra Member
How much voltage have you tried using it with? The more voltage the more current and power is generated. Several people have used the 1000W modules with a 48V power supply and are able to heat items as thick as 1”.
ok, I got mixed up on which one I have. Turns out mine is only 120w
This one
I've only run it from bench power supply on 12v. I've only played around with it a few times, and not in a long time.
 

Chris Cramer

Super User
Vendor
Premium Member
I tested the induction heater, and it does work, but I don't know if it performs as well as it should have. I used a 30v 10a power supply which heated a 3/16" steel rod pretty slowly. The water pump circulates water from a bowl of water through the copper tube and back to the bowl which works well. I think it is just because the power supply could not provide enough power, so I chose to return the power supply and the heater. After doing some more research I found a more popular unit on Amazon, and a 48v 50a power supply off a different site.
 

Chris Cramer

Super User
Vendor
Premium Member
I just received a 48v 50 amp power supply for my 3000W induction heater, and tested it out for the first time. This power supply delivers enough current to allow the induction heater to heat thicker metal stock. You can tell that it is drawing more current as you run thicker stock through the coil because the fan for the power supply starts to run very fast; however that requires you to heat some pretty heavy metal, like a 1/4" 1" square tube.
This is only my very first assembly/ test of the unit through quick wiring, I still plan on designing a fully encased machine that is wired/soldered correctly, equipped with a voltage/amperage meter, and a fully sealed water cooling system.
 

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6.5 Fan

Ultra Member
Premium Member
Chris, looking forward to your full build. At a farm show a few years back there was a business selling several sizes of hand held induction heaters geared towards farmers and repair shops. The idea was to use them on severely rusted bolts heating them up and not requiring a open flame of a torch.
 

Susquatch

Ultra Member
Administrator
Moderator
Premium Member
Chris, looking forward to your full build. At a farm show a few years back there was a business selling several sizes of hand held induction heaters geared towards farmers and repair shops. The idea was to use them on severely rusted bolts heating them up and not requiring a open flame of a torch.

Gotta wonder how well that works...... Not much beats an OA rose bud torch......
 

Tom O

Ultra Member
I just came across this in a pawnshop for 40 bucks I think its worth a go.
 

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Chris Cramer

Super User
Vendor
Premium Member
The induction forge has gone fairly well. I finished wiring a fixed multimeter ment to keep track of a device's amperage, voltage, power, and energy. The heater still works as well as it did when I first tested it, but the potentiometer I installed that is normally used for dc motor control did not work with controlling the heat from the heater. I don't think reducing the voltage input is enough to reduce the heat generated by the inductor. I've read more that a change in frequency is also required to control the power output of the induction heater, since it is an ac unit.
It can heat steel rod fairly quickly to bright red, which is enough for shaping wrought iron. However, at 1400 - 2000 Watts most other heaters I've seen online will bring steel to a bright orange or even white forge welding temperature. I'm thinking that may have to do with the size of the coil. In comparison to those high powered heaters, they have much smaller sized coils, which are probably more effective to smaller sized rods with the copper tube coiled closer around the metal being heated.
I did shape a smaller coil with the same sized copper tube, but I need to find a way to exchange the coils without having to open the case and remove the water cooling tubes to replace the current coil. If there is some sort of small water sealed copper/metal fitting that I could slip the copper tubes into for quick connection to the water cooling system, and remain connected to the power output.
 

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Ggordon

Member
The unit @Canadium quotes would cost 2.5 kilowatts of power per hour of running at 100%. So if you dig out a power bill, see what you're paying per kilowatt and multiply that by 2.5 will give you the hourly cost to run the unit.
But you are only running it for like 30 seconds at a time maybe 10 times an hour so in an hour you would only use it for like 5 minutes or about .3 kWh.


Sorry, just reread the post yes 2500 watts per hour of running. So you would get about 3.5 hours of run time per 2.5 kWh of power usage or at $.2 per kWh about 50 cents. Cheap cheap if it does what you need it to do.
 
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