Is a kiln ok for heat treat?

J

joshyotter

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Dec 9, 2007
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I have access to a kiln and I was wondering if that would work the same as a forge for heat treating my blades as long as it heats up to the right temperature. If the kiln doesn't work out I'm going to build a one brick forge. This is similar to the kiln I would use but not the exact model.

http://cressmfg.thomasnet.com/viewitems/ceramic-kilns/firemate-automatic-3?&forward=1

If the exact model makes a difference let me know and I can find out what it is.

Thanks guys,
Josh
 
It should work long so long as you have a way to reach your arm into the 1500 degree deepness of the kiln or use a long pair of tongs.

Be careful, some of those large kilns have "safety" measures to prevent someone from opening them when at temp....

I dunno though....thats heating up a LOT of space you don't need....
 
I believe I saw Steve Vanderkolff used a large top loader like this and put firebricks in it to take up some space and make the blades easier to access.
 
Paragon makes both kinds, so i suspect that they use the same parts for knife ovens and kilns. The only problem might be the previously mentioned safety feature.
 
For the short term, use the best you have available.
For long term, check out Paragon and Evenheat. Both
companys make digitally controlled ovens FOR the
knifemaker.
Regardless of which oven you use, you'll need a way
to keep oxygen from the hot blade, or the blade will be
ruined.
 
You may want to contact the mfg with the model number, these work but large ones may take several hours to get to high temps. I have a small one which heats pretty quickly but I checked with the mfg first. for pottery they will usually load and run overnight.

Heat at 1500 yet alone at 1850 is tremendous, you will need a good glove and some thongs to reach your blades, there are shelves you can stack to put your work closer to the top. Select a glove that your would reach into a camp fire with, because that is the kind of heat you will encounter. Mine is front loading and it burned my work gloves when I went to remove a blade the first time.
 
Ok, thanks for the advice guys. I think I might be able to use a shelf to keep it closer to the top and I'll check on heating times and the safety feature. Also, does a one brick forge give even enough results or should I save up for a Paragon or Evenheat? I'm on a tight budget so I'd like to not have to spend that much money.
 
I have a 3 ring Skutt brand, it draws 60 amps 220 volts, the kiln sitter is a device that you put a pyrometric cone in it, when it gets hot enough the cone melts, the kiln shuts off. My kiln's previous owner told me it cost 12 dollars for the electricity every time she fired it. I could spend a lot of money and get an actual thermostatic controller if I wanted, I will actually build one with a PID and a pair of 60 amp SSRs at some point. I use smaller kilns for heat treating, that one I will use for production of things other than knives.

-Page
 
I used similar to a one brick for a while, I stacked several bricks to give me some more room. I used a propane torch to heat. Works well with O1 and 1095 and other simple steels since you only have to heat to 1500 F, It really would not get to the 1800 -1900 range to do stainless.

If you have several blades ready that you can HT at the same time the kiln is worth the effort, for one or two at a time I found it easier to pull out the forge. I did build a larger forge for bigger knives and use it now instead of the one brick.

I found a front loading kiln for sale on craigslist locally for $300, I am going to add a temp controller one of these days. if you watch local adds for a while and run fast you may be able to snag something.
 
I think I'm going to try out a one brick forge until I can save up for something better and I'll definitely keep my eyes open to see if I can get a deal. Thanks for the advice everybody.
 
Just a story, From the 70's until 12 years ago I paid shipping on steel 3 times per knife, to buy it, to ship it to heat treat, and then to ship it back. this is not an evenheat ad but for the last 12 or so years at the 1975 degrees I treat ats at its been flawless and I treat weekly and sometimes more. I'm almost embarassed to say I haven't even changed the elements in that time.
Ken.
 
OK, since Rob did the hijack first.....
When I read that typo,the mental image of a shapely gal in nothing but heavy gloves and a thong putting something in/out of a kiln just screams "pottery calendar girl".

It reminded me of a shop poster I saw back in the 60's. It had the obligatory large chested beauty wearing nothing but safety glasses and a smile, and standing at a pedestal grinder. The caption said, "But I Always Wear My Safety Glasses". I can't remember, but it may have been an OSHA poster.

Stacy
 
That may be even better than the Stihl calendars! Hot girls + chainsaws vs. hot girls + hot metal: how the hell do you choose?
 
Is it possible to get one of the evenheat ovens and use it during the forging process as well as during heat treat, or is it too slow, or inefficient, or whats the downside of doing so?
 
An electric HT oven will not work for forging. There are electric induction heating units that are super fast, but also super expensive. For forging, nothing beats a good gas forge for ease, speed, and cleanness.
Stacy
 
When I contacted my local kiln specialists about all this I was advised that most pottery kilns use a different type of element to those fitted to specific knife ovens. Opening the door of a pottery kiln while it's 'at temperature' to remove blades for quenching will almost certainly result in the elements burning out in a very short time. Also, pottery kilns tend to be almost cubic inside and this will rersult in a hell of a lot of wasted space that you'll be heating up every time for nothing.
I looked at the options, and the pro's and con's of my various options, including buying a digital controller and building my own unit to fit it to. I ended up plumping for the least painful (although not finacially) and saved up and bought myself an Evenheat 22.5 inch knife oven with digital controller already fitted.

Having not yet used the oven for H/T-ing blades (I have only just put it into my newly built 'shop) but having done a few 'test runs' with it, the idea of forging with it is definitely out of the question. Once the oven door has been opened the temperature drops so fast that it takes an age to get back up to temp. Waiting that long for the steel to get back to temp before giving it a few 'taps' with the hammer each time, you'd be as old as Methuselah by the time you'd made a dozen blades, and you'd be horrified at the power bill too.
 
I snagged a kiln for a $100 off Craigs list. I cut a hole in the top and hung my blades in on a wire then covered the whole with a fire brick. It was way slow to heat up. I finally tore it apart and used the bricks and the switch to built an nice HT oven and got a PID and SSR from Aubreins, new Kantal A1 wire from Pelican and it is sweet.
 
Pottery kilns generally use Kanthal or SS elements. SS elements aren't any good for cone 10 kilns like the OP is looking at. Kanthal is more likely to burn out the more you expose it to air at temp, even in knife ovens. That's why you should close the door on the oven after removing the blade.

If the kiln is a good deal, I say use it, even if you have to replace the elements. $50 or so should be more than enough to replace your elements when the time comes. A cheap "knife" oven starts at around $400 and goes up to the thousands. I think the small evenheat is around $700. If you can get a deal on a free or cheap kiln, I say put some bricks in it and go for it. You're going to be a heck of a lot more accurate than a one brick forge and it'll give you the ability to do air hardening steels.
 
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