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View Full Version : Convert your pottery kiln into a heat treat oven



Jason Wilder
11-09-2011, 12:04 PM
I was fortunate enough to buy a Paragon A88B pottery kiln at auction for $20. It was in good shape, but when I hooked it to my newly ran 40 Amp 220 circuit, I found that it took several hours to get near useable temps. If I recall, after 3 hours, it was only at 600C.
Here is a pic of the kiln. It is not mine, but a pic I found online.
http://i.ebayimg.com/t/kiln-ceramic-pottery-2300-deg-Paragon-A88B-/00/$(KGrHqJ,!iIE4rL+RwiQBOSUbVI63g~~0_3.JPG

I know that many knifemakers have this type of kiln and cut a hole in the lid to be albe to drop a blade into it from top. But I didn't want to pay for electricity to heat a kiln that was too large for what I need, so I looked into building a kiln.

The big problem here was the price of supplies. Who wants to pay for $6 per soft firebrick just to have it break during shipping?!?!

So my solution. I had a knifemaking kiln right in front of me, all I needed to do was make it smaller. I spent about $60 in angle iron and a couple of hinges from Tractor Supply and that is ALL I spent on this kiln.

I used the old kiln's lid and floor for this one as well as the pre grooved firebricks. The old kiln had four 220v heating elements but since I only needed one, I have set the other three aside for future use. I had to cut off about 4' of the prestreched element to fit it into this kiln. After I cut the end off I straightened out with a propane torch, bent about 6" back on itself and twisted it while heating. I was able to use the same element connecters (after buffing them to get off the corrosion), the element spacers, metal heat sinc, infinite heat control and power box.

Since I was only using one heating element, I could use 110 instead of 220v, which is a plus as long as I use the right guage circuit.

To go along with this is a digital PID controller that I built from a kit on ebay. This is a stand alone box with the ability to hook up 110 or 220 up to 40 amps. It has two SSR's with heat sincs and a computer fan on each end to create air flow across the PID and SSR's so nothing will overheat.

I hooked it up last night and it got to 800C in less than 15 minutes. One thing that concerns me is that during the 800c hold cycle, the temp varies between 790c and 810c. This may or may not be a problem.

http://i450.photobucket.com/albums/qq229/Jasonwilder/Wilder%20kiln/WilderKiln1.jpg

http://i450.photobucket.com/albums/qq229/Jasonwilder/Wilder%20kiln/WilderKiln2.jpg

http://i450.photobucket.com/albums/qq229/Jasonwilder/Wilder%20kiln/WilderKiln4.jpg

I built it to mimic a 14" paragon kiln incase I ever need to buy more elements than I have. Inside dimentions are 4.25" high x 5.5" wide x 14" deep

I used my bandsaw to cut most of the bricks very quickly. There is firebrick dust and scraps all over my shop!

http://i450.photobucket.com/albums/qq229/Jasonwilder/Wilder%20kiln/WilderKiln7.jpg

Old Kiln - $20
Hardware - $60
Digitally Controlled PID - $130
New knife kiln that I build myself - Priceless!

Thanks for watching. Comments welcome.
Jason

Darrin Sanders
11-09-2011, 01:17 PM
Way to go Jason. 800c in 15 min. on 110 power is awesome. Wish mine was half that fast.

Jason Wilder
11-09-2011, 02:55 PM
Thanks Darrin,
When I finished the door last night and fired it for the first time all put together, I sure had my fingers crossed! I just knew something would go wrong but I'm good for now.

Diamond G Knives
11-09-2011, 10:41 PM
Looks like an awsome build for a great price!
Good Job!

God Bless
Mike