PID Controlled Forge/Heat Treat oven plans & WIP

[nickandersonart]

Hey everyone, so here are some photos of what I have going right now with the PID controller hooked up to a venturi forge. I still haven't build the blown forge yet, BUT, the controller worked so, so well with the venturi forge that I at least wanted to share that too for those that are working with a venturi and just want to add some extra control to it.

For anyone wanting to set this up, I also highly recommend the muffle. It helps so much to get that even heating.

I also added another level of bricks to my venturi forge which, while using a bit more gas to heat, does make for a really nice even heat when doing HT. I'm considering having a removeable floor that goes on top of the muffle for when I just want to do forging (thus again reducing the amount of interior space that needs to be heated). I would also then create a second inlet for the TC that I could place on the top floor when doing forging. Would be sort of a 2-use venturi forge then, forging on the top, HT on the bottom. If that all sounds confusing maybe the pics below will help

Here's the finished controller shown in the housing. Main switch activates power to PID, and the side switch cuts off the 12VDC supply to the SSR which disables the PID's ability to control the 220VAC output. This means that it can only read the temperature, which is sometimes useful

Here's the other side of the controller. The bottom cord is main power, the top gasket is the TC wire (extends out of the controller about 15" and then has a female plug for switching to different TC if desired). The middle plug is a female panel mount plug which controls the SSR output. Currently I connected my solenoid to this male plug, which then plugs into the side of the controller. This system allows the controller to also be used to control tempering oven, etc.

Until I build the blown forge, I have the PID controller hooked up to my 2-burner venturi forge. I extended the height for more even heating of the interior, and put a muffle inside along the bottom for heat treating. The TC comes into the side of the forge, and into the muffle as well

Another shot of the venturi forge showing the solenoid gas hookup. This will be done more beautifully in the future For now please excuse the dirty shop haha.

Here's a picture of the A/B gas setup with bypass and then solenoid, each with its own needle valve for controlling the flow.

Here's the muffle for heat treating along the bottom of the forge, where you can see the ceramic TC sheath going into the tube. The muffle is approximately 1/4" (~6mm) steel, 24" (61cm) long

Another shot of the forge interior with front door brick partially in place

A shot of the inside of the muffle where you can clearly see the TC inside. I also have placed two long 1" bars of steel which serve two purposes - acting as a heat sink and keeping temperature even across the length of the blade (great for longer blades), as well as acting as a means to hold the blade upright in the muffle while doing HT.

The back of the forge with muffle sticking out.

A shot of the side where the TC is coming in. Again please excuse the dirty shop

As the blown forge body comes together I'll post more pics. Happy to help out with questions if anybody is curious about any of the build so far.

 

[nickandersonart]

Thanks Dixieblade, yea Fred was a good source of encouragement in the build and helped out with some good advice for sure. Was over my head at first but have a pretty good grip on how it all works now Now just to not get too out of hand with building the actual forge! I was scheming up a ribbon burner or maybe a bunch of small burners but am considering going simpler again and doing 3 small burners. We'll see )




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[cooeyinc]

Was hoping I could get some suggestions from you?? I am wanting to build a PID Controlled round horizontal forge... was thinking
Forced Air
Ribbon burner
Burner placed sideways at the top to swirl the heat
Using a second propane needle valve so when the gas is shut off there will be a lower pressure gas still running (lower temp. Setting) and the blower stays on...

Plus digging through this and many other posts for more details


Any thoughts/improvements???

Thanks
Cooey

 

[Stacy E. Apelt - Bladesmith]

Welcome cooeyinc. You may not have noticed that this thread is several years old. It is best to start a new thread if you have questions, but this particular thread will be left open because it gets lots of reading.

The stickys has a whole section on PID control including my tw0-stage PID control burner plans. There are also articles on ribbon burners. The custom search engine in the stickys also will find threads on things like Fred Rowe's ribbon burner forges.

 

[Crocus88]

I'm resurrecting an old thread but it was on the HT sticky, so...

I managed to find insulation bricks here in Croatia, I plan to make my HT PID oven by the end of the year.

I believe these bricks will be good but if anyone can take a look at the specs and confirm, I would be greatful.

Max temp 1250 °C
Density 550 kg/m^3
Thermal conductivity @ 1100°C is 0,33 W/m*K

Thanks

 

[John mc c]

Resurrecting old threads is not the done thing here crocus. Either is not listening to the mod stacy
If you start your own thread you will get lots of help

 

[Stacy E. Apelt - Bladesmith]

Those are 2300F/1250C soft firebrick, usually called K23 in the States. You want the K26 2600F/1425C type if the forge will be used for forging.

If you use the bricks you listed, the forge will be fine for HT only, but won't last as long if you do general forging in it. It also will not work for welding.

 

[Crocus88]

I will use them for HT oven only, with coil elements.

I have a 2BF and will make a coal pit for forging a bit bigger tools, but the oven will be for HT only.

 

[Stacy E. Apelt - Bladesmith]

Sounds good.