Heat Treat oven or Kiln?

[aliva]

I'd like to build a heat treat oven. I've seen several plans on the net and they don't seem to be to difficult to build.
I've checked various sites where I could just buy one already built, this would certainly save a lot of time and effort. But the pricing is more than I'd like pay.
So I got to thinking why not buy a used ceramics kiln, there are a lot available for reasonable prices. Most will produce a max temperature of up to 1800F . more than enough for my needs
Some kilns have manual rotary temperature adjustment, but I'd prefer a PID controller. which is not difficult to add in the future.
My question is can a kiln substitute for a heat treat oven?
Has anyone done this/?
Any thoughts would be appreciated

 

[Bobw]

Heat treat oven = oven that gets really hot.
Kiln = oven that gets really hot

Therefor.

Heat treat oven = kiln.

Been done before.. Watch Cragslist. Even out here in the middle of nowhere, kilns show up quite often for cheap,
I got one 18"x18"x12" sitting at the shop that I picked up for $50. You could also try looking for welding rod
drying ovens, depending on the size of parts you want to play with.

Just re-read, and you've already seen they are cheap.. Go for it.. If the pottery people were smart they
would start selling their kilns as heat treat ovens.

 

[R_Audano]

I'm the proud owner of a Kiln picked up on a local auction service. It will be great for stress relieving cast iron straight edges up to 30" and has a max temp of 2350 which is plenty for any hardening of tool steels. It has a programmable control, works great and has resale value. It does help to understand the pottery/ceramic lingo but with time it can be translated. Craigslist = good deal with patience. Buy low, sell high and upgrade. The controller for the kiln will also make a very nice controller for a custom stack of refractory bricks with appropriate heating elements. All depends on your checkbook and ambition.

 

[Hazzert]

One consideration I've heard in regards to using a ceramics kiln as a HT oven is the top loading aspect since ceramics are usually loaded when the kiln is off as compared to the HT oven already being at temperature and the heat losses associated with it. I don't have one so I don't have any firsthand experience with either but the posters that commented on it made it seem like a big enough difference to matter.

 

[jscpm]

You could certainly do this. The main issues are the following:

- ceramic kilns tend to be round with an opening at the top, not convenient unless you are heat treating large cylinders

- ceramic kilns tend to be bulky, not the kind of thing that fits on a benchtop the way metallurgical ovens do

- ceramic kilns fire at one temperature; heat treat ovens usually have an expensive controller that lets you run a program with different times and temperatures

 

[Joe Gwinn]

I converted a $100 kiln (with swinging door) from Craigslist to a heat treating oven by replacing the mechanical temp controller with a PID oven controller from Omega Engineering. It was not hard.

 

[Dave G.]

I agree with the previous posts - old kilns have a mechanical control that uses melting cones to control the max temperature and external switches to control the heating zones. You can modernize the controls for the cost of a TC, relay, and controller. I would look for a kiln with a front loading door, otherwise buy foundry gloves like they use to pull ladles out of a furnace.

 

[Shaybuilder]

I bought a new kiln with a programmable controller for heat treating cast iron in order to eliminate the hard spots in thin sections of the castings that cool to fast. It has the capability of controlling the cool down cycle which is needed for my purposes. It works fine for my purposes and was a lot cheaper than buying a heat treating furnace.

 

[James Lederer]

Glass fusing and slumping kilns are often shaped more like heat treat ovens. You can add them to your search terms.

 

[adama]

Its one of the items on this years build list. good ones new go for crazzy money. Local secound hand ones in this kneck of the wilderness are in bad bad shape, some of the glaze fumes seam to be pretty corrosive.

Partner wants to make glass slumped tiles for the whole kitchen. Me i want heat treat options, hence seams a ideal meet in the middle kinda thing.

Elements and proper bricks are cheap enough. Kilns are little more than a angle iron frame - box. Controls even are pretty dang cheap. My searching new, im looking at north of £1K over here for my needs. Parts bill is more like £300 and i can have it the narrow longer shape i actually need rather than the typical cube or hexagon shape of most smaller cheaper kilns. Hence build makes way more sense at this point.

Current hold up is element holders, i know that means T slotting the bricks to use em, but i think it will be worth it. Im looking at wanting a good couple of hundred firings in the 1000C range.

 

[oldbikerdude37]

I agree that the prices are absurd on some ovens.

Ceramic kilns are modified, controller upgrades all the time by the glass artist.
They rework them to overdrive way up till the elements are close to liquid 2,500F and melt 30-40 pounds of borosilicate glass till it can be drawn out into rods or tubes. Run the kilns full bast for days. I dont know how they get them to go do high past the normal 2,350f.

Pretty wicked hot kilns can be made for $200-$500, easy stuff for the members of this site.
I have been on the hunt for a few months myself. Ugly is fine by me, Im going to put new elements in it when they burn up and run it full blast anyway.
I have a nice new digital kiln but its too nice to abuse, I use it to anneal.

$63 and you have a computer controlled oven, I would go with a much nicer control with touch screen and WIFI but im already deep in this money pit.
PID Temperature Controller Kiln Probe SSR Relay HS 40A
PID Temperature Controller Kiln Probe SSR Relay HS 4A Paragon Pottery Glass FdegC

Small digital kilns can be had for under $1,000. 14.5 x 14.5 x 6.5 1,700F
Buy Skutt FireBox 14 Glass Fusing Kiln - Clay-King.com

If you do need a real oven with atmospheric gas injection control too this is more reasonable at $2200
Paragon HT22D Kiln for Knife Making - Clay-King.com

http://www.clay-king.com/kilns/heat_treating_kilns_and_furnaces.html

If I wanted the big monster kiln I would talk to the folks at L & L Kilns
Kilns: Industrial & Commercial Kilns, Industrial Furnaces, and Large Kilns for Artists | L&L Electric Kilns - Built to Last