View Full Version : Homebuilt heat treat kiln


dudeinthehut
04-07-2005, 03:50 AM
Bill and RJ were kind enough to answer my questions on the nitrogen/tempil-stick thread. Thank you gentlemen.

However, since my gas forge won't do the job, I am now left with a choice. Outsource my ATS-34 and other "demanding" steels for heat treat or find another way to do it myself. I choose to do it myself.

So, I am probably going to need a kiln or a furnace capable of close to 2000F. I am convinced I can build one. Let me run this by ya'.

I start with a large steel hand-carry toolbox. I figure I can line it with firebrick or even two layers of blanket to be safe. If I go with blanket, I can suspend the two rows of commercial elements (110V/2200F rated), with heavy guage, high temp wire shaped to do the job, from the lip of the open box. Understand that I would wrap a few inches of the blanket over the lip of the main box and the lid for a good thermal seal. Thus, the element suspension wire would not touch any part of the box, just the blanket. I found a new pyrometer and thermocoupler for $50 on ebay.

Where I run into a road block is with temperature regulation. If you couldn't tell, I'm trying to see how inexpensively I can make a functional kiln with satisfactory performance. With that in mind, I figure any switch that can handle 110V should do. BUT, would a standard dimmer switch made for lighting be adequate for temp regulation. Help me here, because I'm no electrician! If it won't work, what will? Could I just use an on/off swith and cut a series of vents into the exterior of the unit to bring the kiln down from it's maxium operating temp (whatever that winds up being) to the target setting?

As you can tell, I have several ideas. I just wanted to bounce them off of the experts here in the hopes of saving time, and of course, money.

I figure I can do this for $100-$150 if something similar to my plan works.

Thanks for reading this guys!

Andy

twisty
04-07-2005, 04:13 AM
Here's a tutorial on a homebuilt HT funace. Looks quite good.

ht furnace (http://www.britishblades.com/home/articles.php?action=show&showarticle=31)

Trenton

Bernez
04-07-2005, 05:41 AM
Hi Andy,

I've got one of these (http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=42897&item=7506509795&rd=1&ssPageName=WDVW) on E-Bay (tip from Andy Gascoigne). They go to about 1200C/2200F.
It comes with a thermocouple and a heavy duty relay.
There's no wiring diagram with it. But I've found some info here (http://www.turningwood.com/home_furnace1.htm) and here (http://www.diybanter.com/q-t_11600-Slightly-OTWiring-a-Thermocouple-for-home-furnace.html) .
You can't program the controller, just set up the wanted temperature (low cost ;) ).
I didn't install it yet, so I can't tell how good it is.

Hope it helps,

Bernez

HellForged
04-07-2005, 10:34 AM
A few things... I would use soft firebrick and not blanket.... and I would carve grooves in it to support your elements. you could use blanket on the lid of the tool box maybe but if it were me I would make an opening in the side that I could put the blade in and out of. Oops nevermind just read the tutorial... everything in there you should follow exactly. Have a good day.

dudeinthehut
04-07-2005, 10:15 PM
Thanks to all for the tips!

I think I will go with the brick and grooves. Now all I need is time and money...

I'll post pics when finished.

Andy