Temperature controlled forge.

Hello I am new here, but I would like to know if my project is feasible.

I would like to create a temperature controlled forge using some of This, I would like it to get to temperatures hot enough to Heat treat blades(~1000C).

I can insulate it but I need to know if it is possible to control that much current with an arduino. the temperature control does not have to be very accurate ( +/- 50C), but if anyone can lend me some help that would be awesome.

lolzcat88: Hello I am new here, but I would like to know if my project is feasible.

Yes.

lolzcat88: I would like to create a temperature controlled forge using some of This, I would like it to get to temperatures hot enough to Heat treat blades(~1000C).

Make sure that the heater element you intend to use is able to cope with such an heat.

lolzcat88: I can insulate it but I need to know if it is possible to control that much current with an arduino.

It's not that much, actually. A decent relais (220V AC/16A or more) is fine.

lolzcat88: the temperature control does not have to be very accurate ( +/- 50C), but if anyone can lend me some help that would be awesome.

A K-Type Thermocouple is what you need. There should be plenty of tutorials how to use these with arduino.

Cool project, good luck :)

lg, couka

lolzcat88: using some of This

It says "Material: 0Cr25Al5" which doesn't make much sense but maybe it's the typical Chinese bad description and they actually mean it's a Kanthal type element which should work for your application. The big issue I see with that element is it doesn't have pigtails. Typically kiln elements will have a section on each end that is doubled over and twisted, called the pigtail. This decreases the resistance of that section so that it won't get as hot. You need to make a solid electrical connection to the ends of the element and if they get glowing red hot that's not going to be possible. I use brass bolts and threaded bus bars on my kiln to connect the elements and have found that to be far superior to the crimped connectors you will find in many commercial kilns which tend to loosen up from all the heat/cool cycles after which the poor connection causes them to burn out. That's been the cause of the only elements I've needed to replace in 14 years of full time use but I'm operating at 565C max.

I'm using the MAX31855K breakout board from Adafruit: https://www.adafruit.com/product/269 with this library: https://github.com/RobTillaart/Arduino/tree/master/libraries/MAX31855 to read my type K thermocouples.

Hi,

Welcome to the forum. As said, an Arduino will do the job nicely. What is your electronics, programming, arduino, hardware experience?

This is going to need some pretty good mains wiring, simple but high current and high temperature. Have you got a kiln you can wire up or are you building from scratch?

The actual element control device, contactor, not relay to small, will have to be rated for the surge current that will flow when connecting to a cold element.

Have you calculated the power needed to get your kiln up to the temperature you require?

Thanks.. Tom.. :)

TomGeorge: The actual element control device, contactor, not relay to small, will have to be rated for the surge current that will flow when connecting to a cold element.

Hmm.. my idea was that the surge current only flows the first time, because after that, the heater stays at around 1000°C.

But you're probably right :)

lg, couka

Something I've added to my kilns, after a couple of costly lessons, is a limit controller. This is a setpoint controller set a bit above the highest temperature that the kiln should ever achieve under proper operation that controls power via a separate contactor. This prevents the kiln from ever going into runaway heating if the primary temperature control system fails. If your forge is properly designed and no flammable materials are too close, runaway heating shouldn't cause a fire hazard but it is likely to be hard on your furnace, elements, and may damage whatever is inside the furnace at the time(in my case it means a puddle of glass that used to be a whole days worth of finished product fused to the floor of the kiln). Mechanical contactors have a fairly common failure mode of fused contacts where the thing actually gets arc-welded into the on state. This can be avoided by the use of a mercury relay. With a home-made temperature controller this is an even more important feature although I have experienced multiple runaway heating events caused by malfunctioning commercial temperature controllers and have never had a problem since I made my own.

Hi,

Something I've added to my kilns, after a couple of costly lessons, is a limit controller. This is a setpoint controller set a bit above the highest temperature that the kiln should ever achieve under proper operation that controls power via a separate contactor. This prevents the kiln from ever going into runaway heating if the primary temperature control system fails.

Yes, I have done similar, use a separate system, separate Ktype and simple controller that is interlocked with the contactor coil. In the application I was building, the kiln was heated from ambient up to 1300C on a profiled ramp, so I also had a software watchdog timer that monitored the output ON time. Tom.... :)

Hello, Thank you for all your replies
First off the questions

TomGeorge:
What is your electronics, programming, arduino, hardware experience?

little, I do know basic programming and have been experimenting with arduino.

TomGeorge:
This is going to need some pretty good mains wiring, simple but high current and high temperature.
Have you got a kiln you can wire up or are you building from scratch?

I will be building this from scratch and from silica fire brick most likely, very much like this person, but higher temperature and temperature control.

Now secondly I am thinking to use a relay and some code that says if(temp < target) - turn on coil, else - turn off coil, for some very easy settable temperature control.

lolzcat88:
Now secondly I am thinking to use a relay and some code that says if(temp < target) - turn on coil, else - turn off coil, for some very easy settable temperature control.

Don’t forget to implement some hysteresis!

lg, couka