Heat Treat Oven...

[Ray C]

2350 F.... Are they making synthetic diamonds in there? LOL...

Anyhow, glad you were able to come to the rescue on that unit. It's amazing how expensive they are. All total, I probably sunk about $375-400 in mine. New... 2, 3, 4 grand -easy.


Ray

 

[countryguy]

Ohh brother- Here I go again- Newb into the deep waters. I wanted to add some things to this post about refractory's beyond Kaowool insulators.
It seems the Thermolyne my Son and I are rebuilding had A) non-insulating refractory material which had the 3/8" coils encased inside which comprised the actual chamber lining. B) Then really thick insulating and super soft stone around that. I think someone called it soapstone? Does not seem like firebrick- That is for sure.

The unit had 2 bad panels. $390 a piece for 9x13 inch A1 Kanthal replacements. Ummm No way. Did our Research (we hope) and learned we could/should be able to make our own. Used a Mizzou based non-insulating refractory. Mixed, poured, and now installed. The dryout times for Mizzou are a bit complex but I hope it'll pay off. time will tell. Wanted to add another option to the mix here for possible muffle type panels . with them installed it is really hard to tell the originals from ours. I just hope they last!

PID from: http://www.automationdirect.com/adc...s_Controllers/1-z-32_DIN_Size_(SL4824_Series)

TC and TC Wire from AD as well. Lots of options!

Mizzou castable mix from Toledo OH refractories. $53 for 55lbs I see now that refractory shops are abundant out there. Pizza places? ;-)

After all that- I should have just bought a new HT oven. simply did not know about an HT oven -vs- the 'muffle furnace' we were given as junk. When you look to Evenheat-kiln.com which is about 1.5 hour from me, a nice 18 or 22" deep x 10"w x 6"T can be had for $700-800 bucks from the right distributor (we like usaknifemaker.com) I would order if I had to do it all over again, but boy did we learn yet another skill and I have a 2nd thermolyne to build if I choose I guess.


CG.


44

 

[countryguy]

Update: Info on the overall build to the oven in the post above is finally to final phase. I elected to keep adding to Ray C's thread since there is so much info here and I felt the Mizzout and PID parts could help someone as part of the overall thread?

The Soho PID temperature controller is in.($80 to 130) The TC (Thermocouple) probe is in($30-45). The TC wire obtained. ($35) The USB to 485 comms adapter ($13) is installed. Each are shown in the Circle's in the image below of the bench test setup. The new panels we poured are installed and connected. The way we hooked them up is shown in the hand drawn note (pic) below. I set it up for 24Amps. We have heated the new panels up to 500F on the bake cycle but need to get to 1200F which I could not do w/o this setup from Automation Direct. I must say I really like these guys! Great CS. No hassle on returns. Great docs and instructions (to me anyway).

To make this all work; I have 2 sets of 3A NO contacts on the SOLO PID controller. I'll use 1 set to trigger a 110VAc coil large contactor which will place the 240VAC & 24Amp draw on the coils. I know a lot of folks on the ebay PID sales use the Solid State's. Same w/ Ray & Co's notes here on this thread. I'll ask why on a HM thread later today as I'm wondering if there is some reason I need to use a SS type relay?

The old controller: Honestly I do hope to keep it around and leave it attached. Just old school cool looking.