Oven Ramp speed question

I

itrade

Joined
Jul 3, 2002
Messages
645
Well my infamous EBay oven is here. And it works! Someone converted it to an Orton AutoFire Unitemp. Programmable, soo cool. However, I have a little issue with it:

The fastest ramp speed is really slow.

It doesn't have a "Set the temp and go mode" - that I can find. It seems the fastest I can go is 999 degrees an hour and then a speed up mode of 40%. Basically that means one hour to reach 1400 degrees.

I have another controller that is just on/off. Can I use that? Or is there a reason ovens should have a slow ramp time, besides for ceramics?

Steve

PS heat treated a 52100 blade with it. I'm gonna like this!
 
One bad thing about a fast ramp from a cold start is over heat. I have found this true on my Even Heat. I found this out the hard way once when using my Even Heat to temper a blade and putting an oven thermometer in the oven with the knife (I put the oven thermometer in there to check its accuracy). I set the oven to ramp as fast as possible. Upon reaching the 400 degree set point I looked at the oven thermometer. I was about 80 degrees high. I now ramp slowely for tempering or get the oven stabilized before putting the blade in it.

Great that you were able to get the oven after all. Now start shopping for a good dewar.

Roger
 
One hour to reach 1400 is pretty quick. If it is programmable you can do a LOT of custom heat treating with it, none of which needs to go anywhere near as fast. there are Materials that require slow ramping heating and cooling that will result in incredible edge retention and durability. have fun!
 
Thanks Guys,

I guess all I need is patience. And I want it NOW. ;)

I'll leave in the controller, clean it up, and have some more fun.

Steve


Roger, I'm watching dewars on ebay. But, the's a guy I know here in town that owns a dairy. I'll see if he's got a semen tank. Maybe I can drop the odd blade in there.

I priced the liquid nitrogen. I was quoted $30 for 4 liters - sounds awful high. Is it?
 
I'm paying about 68 bucks after 6% sales tax for 20 liters. Your price is way too high. Shop it. Better yet ask the dairy guy where he gets his.

I got my dewar off Ebay. I got a real dandy. I see the same dewar there every so often. If you like I'll keep an eye out for it. About the minimum price for it is about $350. Let me know.

Roger
 
for a sec there steve i thought you were useing bull semen for a quench:D lets us know how that works out? LOL. i wont be there at bakca this year, but it was great meeting you last year and seeing your first two knives. man have you gone far in only a year!:)
 
Bull Semen is effective for surface hardening. The practice started in the earily 1550's in Spain. Legend has it that someone was having trouble clipping the hoofs on his bull. So, he brought the bull and the snips to the blacksmith to demonstrate the problem.

The trouble started when the bull (who had been pent up for a little too long) got excited about the cow that was in the next stall. The smith happened to have a few irons in the fire. Well you can figure out the rest. The farmer was mortally wounded in the mishap. The coal fire was knocked over and the irons were sprayed with ... well you know.

While cleaning up the place the smith discovered the strange properties of case hardened steel.

Until the infusion of carbon into the surface was understood, people had no idea of how the process worked. Nor did they care. But every year the town would keep one bull locked up for months and sacrifice one farmer.

Such is the mystery of steel.

Steve
 
Steve, get yourself some high temp. foil so you can do the supers and other air quench steels. Enco often has it on sale. I can't remember exactly but I think I paid about 80 bucks for a roll of 2 Ft. X 50 Ft. from Enco.

You don't want to HT the supers without atmosphere control. The decarb is far to deep otherwise.

RL

P.S. - about your 'bull' story: I thinkst that is exactly what it is. If it were true we'd be quenching our blades in the closet.
 
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