Use of oil for tempering?

C

cooks 7

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Jan 27, 2005
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I have been using my kitchen oven for tempering the few blades I have made. Recently I read about how much kitchen ovens can vary in temp., so the search continued for a reliable/consistent source for tempering heat. Then i found a toaster oven and put it to the test with my thermocouple. it maintained an even temp for about 15 minutes, then continued to drop temperature by cycling shorter and shorter. it finally settled around 360 degrees, no matter what i turned the temp dial to.
So the search continues for a consistent method for tempering. So the question so long in the making is... can you temper a carbon steel blade in an oil bath to ensure proper temperature regulation? if so, what method, tools, oils... do you use. i was thinking for smaller blades, a gas range and a pot full of olive oil and a good thermometer would work, anybody use a similar setup for tempering?
thanks
Jon
 
Any kitchen oven should be checked with a thermometer. You can improve the oven by using something like a 'baking stone' or 'pizza stone' which is a ceramic plate about 1/2" thick , or some firebricks .This will even out the temperature cycles [also good for bread , roasts !!] . For oil you have to be very carefull about flash point ,it must be well above tempering temperature for safety...I'd use the oven with bricks.
 
Not sure I would usw oil,but you can temper in molten lead or the hot salt pot.years ago there was a article in Blade about covering the toaster oven with insulation to keep the heat at a more even temp.

The oil just sounds to Fire risky:eek:

You could make a heat treat oven then use that as they hold heat and temp allot better.

Bruce
 
I just did a hunter OSB (OLD SAW BLADE) in a frydaddy.

I get a steady 350 untill I quench the blade. It will rise about 25d. each 3-1/2' hunter I quenched in the hot oil. I did three blades, the oil temp rose to 425. I left the blades in the hot oil for two hours. The oil temp dropped pretty quickly back to 350.

I haven't sharpened the blade enought to do a brass rod test. But I can chop small pieces of a mild steel block. With the blade as it came out of the oil, no damage tot he blade.

I'm pretty happy with the results so far, but I need to do more testing. :)

Another method is using hot glass beads. I tried up ending the toaster oven and filling it with glass beads. The beads melted around the elements and ruined the toaster oven. DUH :rolleyes:

My older toaster oven was almost dead on with A 10 TO 15 DEGREE VARANCE WHEN IT CYCLED. I don't think that is significant. When set below the required tempering temp. I used a scrap piece of kwool around the toaster oven. I can say this did improve the oven.

The older toasters worked much better than the new ones, well the new Black and Decker Oven I bought sucked. it would bounce maybe 50 degrees.

Probably replacing the oven controller with a more accurate controller would be a simple cure.

Somewhere I think it was Farshow Magazine, a man built an oven fro curing powder coated products. He used standard oven elements and a decent controller. His ovrn can handle 10' hand rails.

Tempereing in lead is what is suspected, lead to William Scagels Death. :eek:

Ebay is a good source of bargain controllers.

My .02
 
was talking to my friend at lunch today, he makes beer sometimes and has a johnson controls temp controller, they are pretty accurate, and could be adapted to run just about anything, i.e. toaster oven, or roaster. assuming a roaster could actually reach tempering temperature, the dial on it said a max of 500, i would think it could do a good job of heating oil. i would think something like tough quench or the like with a high flash point would be fine/safe at around 400 degrees. i wouldn't think it would matter too much what oil you used as long as it was safe. it would be kindof like a salt pot i guess, but with oil instead of salt, or i guess i could use salts, honestly the idea of molten salt scares me more than hot oil... to each his own i guess
 
Raymond,
I wish I could do something like that, for now though, I can only afford to mess around.
 
I know of one fellow who had an old fry vat from his restaurant.He uses it to temper his blades in.Puts them in the basket and lowers them in for 30 minutes.Cools them ,and gives it another 30 min. dunk.He says it works fine.He does it this way because he already had a fry vat. A good HT oven would be more economical if he had to buy a vat.
 
Peanut oil has the highest flash point. Thats what I'm useing, left over from the Fried TUrkey at Thanksgiveing.

Tempereing in oil is just a medium to trnsfer the heat to the blade. its technically more efficent than hot air. I think Don Foggs site was where I saw mention of useing glass beads. Just don't use em on an open element.

one stove top element + one good controller + SS chinese cooking pot = one tempering rig.

Max Burnett did some exploration into the hot oil quenching a couple years ago on the outpost, you could probably find his results in the search function over there.
 
cooks 7 honestly the idea of molten salt scares me more than hot oil... to each his own i guess[/QUOTE said:
funny how that works 500 is 500 no mater if its salt or oil :D
i know the oil thing doesnt worry me as much also i did think about the fryer deal as i have a frydaddy but the mess in using it and not the kiln not worth it for me
btw i temper my cpm3v for 2 hours at 1000 3 times and its been to long to remember how long i was tempering the 440c i think it was just an hour 2 times
butch
Click to expand...
 
i know the oil thing doesnt worry me as much also i did think about the fryer deal as i have a frydaddy but the mess in using it and not the kiln not worth it for me
Click to expand...

Well I'm quenching the blade in the hot oil as well as tempering. On a small scale the frydaddy is easy, one shot leave it be until its tempered kinda thing.

Of COURSE i'M NOT DOING SS STEEL. So that makes a big difference. :)

I think Laredo was useing a mix of half salt and half snomelt for the same thing. I do know hot oil makes your skin kinda crispy in a short time.

You just hafta refrain from stickin your fingers in the oil and then lickin them. :p
 
Hey Sweany, do you recall where you heard/read that Mr. Scagel used molten lead to temper, etc, then died from it? I have never heard that before, but there's lots I haven't heard:confused:

Years ago I got taken in on a Infomercial, for a oven called a Swirl-Air oven. It cooks by using pipeing hot air, reaching around 450 degrees, swirling around inside the pot. I might pull that silly thing down out of the rafters and see what it does using my Rockwell meter. I'll admit that it cooked really good.:D Now to remember which rafter:jerkit: (been wanting to use that new smilie).
 
I think it was on the net that was the "suspected" cause or at least a contribution.

not sure of the source, just something i remembered.
 
I just looked up the melting point of pure lead...... 621*F. Maybe an alloy like babbitt (mp approx 450*F)?
 
For in the general house area tempering I'd find an oven and a reliable thermometer(s). Even for heating my quenchant oil I use a crock pot, no heat source flames (danger).

RL
 
I was thinking Lead was around 450- or so.

I can run a Turkey cooker without frying myself. :) and well heck ever day at McDONALDS THE ged BOYS RUN A FRY COOKER. :)
 
Lead melts at 621F, tin at 450F and a 62Sn-38Pb solder at 361F.
 
I know Dr.Lucie,who was with Scagel when he died.He never mentioned Bill using lead,or dying from lead poisioning.Bill was an old man.
 
Well I might be mistaken about Bill and the lead. But I know breathing lead ain't a good idea, specially if you want to live to be old and crabby like me. :D

I do know the folks that work with lead ona regular basis are monitored quite closely for exposure limits.
 
There was a roaster somewhere i saw rencently, looked like an overgrown crock pot, i might look more into that, i can use an expendable pot like that for quenching anyways, but i might heat it up and give it a try for tempering, check it with the thermocouple and see how it does, the dial went to 500 so maybe it'll work. i looked up the flash point of peanut oil, should be aroudn 600 so i think i'll be okay, plenty of fire protection on hand should help. i am pretty paranoid about safety(and everything else in the world), so i should be okay, thanks for the suggestions and info.
 
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