Homemade HT oven

[10es&]

I am considering building a heat treat oven like the ones on this thread. Would anyone who built one be willing to share what the approximant cost of the build is? I know that using different suppliers for the PID and SSR can be a factor?but I would like to know if there is a substantial savings to building vs. buying used.

[pipecrafter]

All prices approximate:

Mild steel angle and bar from the hardware store - $50
Fire Bricks - $80 for 24 locally
Element - $23 + shipping
PID - $45
SSR - $15
Heatsink for SSR - $10
Thermocouple - $24

So about $250-ish depending on where you source your parts and how much you can scrouge.

[dbalfa]

-to the best of my recollection:

Bricks-24 - $80
metal encasement- $45 (sheared plate to fit)
controls- $75 (SSR/PID)
thermocouple- $60
project box- $20
coil/leadout wire/Htemp wire- $50
misc- $70 (SS bolts, angle iron, hinges, switchs)

Total - $400

I had a lot of stuff around the shop like standard wire for outlet, outlet, switches, power cord etc. I would say if you had to purchase everything, you would be looking at $500- tops. It took apx. 20 hours of actual labor to put it all together (spread out over a couple weeks.)

[foxfyre841]

I'm going to have to agree for most everything:

Bricks-18 - $80
controller- $35+ship (SSR/PID)
thermocouple- $25 + ship
element - $25
project box- Free out of a junk bin
various wires- $50
DPST Switches - $30
SSR w heatsink - $45
Fuses and holders - $20
Plug end - $30
angle iron - $50
Recepticle - $25

Mine is probably a little more tricked out with fuses, wiring blocks, and a separate custom power cord and twist lock receptacle on the project box. So yes 400ish is about right for a tricked out one.

Duralite: for the element and K-thermocouple
lightobject: for the PID controller
Grainger: for the SSR & heatsink and 20A DPST switch
ACE: for the plug ends, wires, bolts/nuts, angle iron, and 10A DPST switch
Marjon Ceramics: for the firebrick (local)

I'm using the two DPST switches to cut power from the element and the PID separately. This is a good idea for anyone building their own oven (don't reach with metal probe into an electrically "hot" area to prevent shocks).

Also, fuses should be used as a safety measure. I'm using fuses (15A for the element and 0.5A for the controller) and holders rated at 20A to 260V for my setup.

Regards,
James

[dbalfa]

.....MAN! - I should've put in a fuse....now I gotta go get one..
I would think simple automotive plug type fusable link would work?

Thanks James!

[foxfyre841]

Maybe. Visit your local ACE or Grainger and pick out fuses and holders rated to the voltage and amperage of your setup. I'm not sure whether fast or slo-blow fuses are more appropriate. I am using ceramic versions of the 3/16" x 1 1/4" glass tube fuses. These are supposedly rated to the necessary voltage/amperage ranges. They are a little over a dollar a piece and one should be put on each hot leg.

When picking out a fuse out of the bulk bin remember that fuses look a like but will be stamped with their rating: sometimes the wrong fuses make their way in with the bulk from careless restocking.

Remember Voltage x Amperage = Power (your 3000W element at 220V will drawn 13.6A so get a 15A fuse with a 20A or better holder)

[Stanton Knives]

Wow I'm taking forever to get this done!

Looks like 110V wiring for controller is the only thing left.

I think Im around 600 but Im not that efficient in planning. Also a used flux core welder and welding table setup, good excuse to get one.

Easier on the wallet one piece at a time..harder on the noggin tho.

[Stanton Knives]

Well after much head scratching and testing it seems my SSR wont close contact. I'm no expert but i do have 12V going to the control leads of a1 and a2. There is nothing I did to short/fry it that I'm aware of.

Maybe I can find a temp solution to adjust it while waiting for another SSR.

Any quick and dirty ideas on that one? Maybe some sort of variable resistor dial from a box store? Basically I have 220V setup with each 110V leg connecting to each end of the heating element, one leg is what I am trying to switch on/off with the SSR. The other leg is direct to the element.

There is a main cutoff switch that cuts power on both legs on front of oven.

I will read up AGAIN on this on the web, maybe find an answer but I have not worked on this project in a quite awhile.

[Stanton Knives]

Heres a couple pics of working oven! The SSR I got from Auberins was DOA unfortunately. Kinda threw a wrench into my works trying to figure what the heck was wrong. I picked one up from Grainger.com and worked immediately upon installation. The Auber SYL PID works great just dont know how to use it. Still trying to absorb the instruction manual.

You can see the heat sink(from Grainger as well) in the pics for the SSR and that is the old SSR not the new one.

I did not seal the bricks but had no issues with heat so far up to 1000 deg. If it becomes any issue i will prob tack thin sheet on to the frame etc but then again there is only 1 little gap pretty much.

The oven took me a long time to get completed, started in Oct., lost interest for awhile but its done and I have several new metal working tools/grinders and a lil welder too.

Now its on to learning HT but a hearty thank you to all you guys for your help. Im more of a tinkerer than a craftsman but I do enjoy it.

[ARCustomKnives]

lookin good!

I really need to get my HTO project started again.
I started cutting the bricks, but I still need to get some refractory mortar, as I want to seal my bricks.

The last thing I will need is shell material and some wiring supplies.

[Stanton Knives]

Originally Posted by Bassthumper

lookin good!

I really need to get my HTO project started again.
I started cutting the bricks, but I still need to get some refractory mortar, as I want to seal my bricks.

The last thing I will need is shell material and some wiring supplies.

Sounds good! I did heat treat my first blade...was very anti-climatic, I was prepared for fire, smoke, burn treatment, etc and I stuck the red blade in the oil and it went pfft and it was over lol. Tempered 2 hrs almost around 475, oven dial not accurate need to get thermometer.

I did have a slight warp after ht and bent it back but its still there, bummer. Also hand sanding the blade, wow thats alot of work. Will look for different processes rather than wrap sand paper around a block, my hands cant take much of that.

[ARCustomKnives]

Well, I figured I'd post a quick update on where I was at on my HTO project.

I finished wiring a 240V range outlet in my garage yesterday. I already had a subpanel in my garage, I just had to wire it to my main breaker box (which just involved splicing a couple cables together) and wire up an outlet from the sub panel.

I decided to go with a 4 wire range outlet so that I could use one leg of the hot and a neutral to power my PID, without having to use a separate supply.

All of my bricks are mortared and carved out, and my element is mostly installed. I just have to staple in a few spots that want to jump out.

I think I pretty much have all I need to finish, except for the outer shell and a few small accessories. I'm gonna try to order most of those today I think. I'm very excited to get this beast finished and working...