I've seen plenty of videos on making a tabletop furnaces out of things like old propane bottles or hot water heaters lined with refractory bricks and the like.  Some seemed pretty nice too, but many were gas fired.

I'd like to go a little bigger and electric.  Without having done more than some very basic research, I was thinking about rewiring a older floor standing pottery kiln to have PID temp/cycle control.  Might need to replace the elements to reach temp, not sure yet.  Probably will depend on what I get my hands on .

Also was thinking about gas purging.  I was thinking maybe one of these kilns could be sealed up well enough to plumb argon into it to displace O2 to a low enough percentage to reduce or eliminate scaling/decarburization.  I'd like to look into this more, not sure if it's possible or even practical.  Might just be a try it and see what happens type of adventure.

Any of this sound do-able?

All of this if fantasy so far, but I need to do something, or find a local heat treater that is willing to take on nickle and dime small parts on the cheap.  I don't see that happening.  Plus it's something I've always wanted to try anyway.

I'm sure someone has done this already.  So, figured I might ask around before I get myself all excited and start throwing money at another hopeless project.

Any thoughts?

I don’t have anything valuable to add to this thread, but I did do this in the backyard today. Attached File

I bought a kiln to do exactly what you are thinking. I never got around to messing with it, and it's taking up space that I could use.

Shoot me a PM if you want it. If you want to drive to IL you can have it.

Someone here did something just about like that a while back. Don't think they were purging it but they either built or converted a kiln to PID control.

I have a tabletop kiln I've (mostly) converted. Needs a new SSR and some bricks repaired. My first test run showed that it was going to take forever and six weeks to get to the temps I needed so I got a new element sized for 240 (came with 120 elecs).

I seem to remember reading that the typical heating element wire doesn't like the purge gasses, but I never really looked into it. Hard to imagine nitrogen would mess it up seeing as how air is mostly nitrogen.

I have heard of guys using Brownells anti-scaling on it during heat treat, but have never done it myself.  I was going to try argon, but never purchased the purge kit.  I just end up sanding off the scale.

I have some stainless foil for air hardening steels, but haven't used it.

I don't know if nitrogen would be a problem at temp either, but I was thinking argon.  I have 2 T size bottles sitting here, so why not try it?  The trick would be getting pieces from out of the kiln and into quenching medium lickety split, or else why bother, I would imagine.

Here is the first post in my thread where I started messing with my converted pottery kiln.  There's a bit of info missing from that thread because I started another one in GD specifically about the kiln/thermocouple/pid.

Long story short, buy a ~$40 pid/ssr/thermocouple kit from Amazon or ebay, toss the thermocouple that comes with it.  Buy a k type thermocouple (i use a ceramic insulated one)that reads in the range you want and get some k type thermocouple extension wire(this is important, you can't just use any wire), mount the thermocouple in the kiln, wire up the stuff and program the pid controller.  Look on youtube for info on the pid if you aren't familiar.  The videos from a dude called "red beard ops" was one of the most helpful for me.

I started the project not knowing a thing about any of this stuff, now I'm heat treating AEB-L fairly often in it.

I'd recommend using 230v if possible. My kiln is 120v and it takes hours to reach ~1950°.

BarZ Industrial offers a nice HT oven for around $1000.  It's also available with an Argon purge kit.

Forget gas purging until you know more and have experience with heat treatment. Just wrap your steel in stainless foil to achieve a similar oxygen shielded atmosphere.

Other than that is just a PID switching on and off a SSR switch powering the heating coils on and off. Pretty straight forward.