Heating Canola Oil in a Cylinder??

Col Defender

Col Defender

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Nov 11, 2011
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Just finished cutting the top off an old "divers tank", cleaned it out and filled it with canola oil. Previously my quench tank was an old army ammo box which worked fine for most of my smaller knives. But I needed something taller and vertical for longer blades and now I have it. But I am not sure how to heat the oil in it; for now the whole cylinder is sitting on a hot plate and that will work for now I guess but it is pretty heavy and I'm afraid it will be too much weight for the hot plate. I thought about some sort of electric immersible heater but fear that could be dangerous.

What is the right way to get the oil hot? I usually go for 110-120 degrees F in my ammo box. And a follow up question, how important really is quenching oil temperature? I'm doing 1084 and occasionally Alabama Damascus. What happens if I just quench at ambient temperature? 50-80 degrees F.

Thanks

Steve
 
Ambient temp will cause a gas jacket to surround the steel and not allow the temp to drop fast enough, thus causing impartial hardening (at best).

To raise the temp in your cylinder, head to your local home improvement store and buy a piece of low carbon steel from their rack (in hardware at home depot). I used a piece that is 1/4"×2"×2' heated in my forge and then dipped that in my oil. I used a digital oven thermometer to check the temp.
 
The oil temperature is related to the speed of the quench. Higher temps will make the oil less viscous (less thic) so it will move heat faster from the quenched piece.
The key point in your setup is to make sure to have the tank stable on its feet, but providing this you can point a flame to the bottom side and regulate it to have the temperature you need... you could stir, but the natural convection will even out the hot oil distribution by itself in such a tube tank.
I do this way, and as soon as i have the temperature i want i switch off the flame and quench.
 
I built a vertical quench tank using some 4" PVC (I lined it with a piece of steel round duct to keep from accidentally melting the sides, never been a problem) and I drilled the bottom out for an electric water heater element, making sure to seal everything up with some high temp silicone. Been working like a charm for years. Right now I just have a simple light switch to turn the element on and off, and because of that I need to be mindful not to leave it on more than a minute. It doesn't take long at all to heat the oil. I use a digital probe style thermometer to monitor the temp, and shut off the element when it's close to where I need it. I use parks 50, but the idea is the same for anything.

Eventually I'd like to build a larger vertical tank out of something like a 6" steel pipe, and control the element with a thermostat or PID of some kind.
 
I just have been using a weed torch on propane and warming up the cylinder from the outside and a turkey deep fryer thermometer to check oil temps. Just takes a couple minutes.
 
I welder a 4" long piece of 1" round bar to the end of a 36" piece of 1/2" round stock. I stick it in the forge as it the chamber warms up, and when it is a nice red I quench it in the oil and stir the tank well. I use a $20 HF laser thermometer (-30 to 500F) to check the oil temp. One heat up usually raises my 4 gallon tank of AAA to 120F. Occasionally it takes two heats. The tank stays warm for a good while in all but the coldest weather.

Note:
Parks #50 works best at 70-80F. It should not be heated above 90F for best results. In the hot summer, 100F will still work most of the time, but you can chill it with a frozen plastic water bottle on a string lowered in the tank and pulled up and down. If the tank is below 60F, warm it a bit before use.
 
Stacy E. Apelt - Bladesmith said:
I welder a 4" long piece of 1" round bar to the end of a 36" piece of 1/2" round stock. I stick it in the forge as it the chamber warms up, and when it is a nice red I quench it in the oil and stir the tank well. I use a $20 HF laser thermometer (-30 to 500F) to check the oil temp. One heat up usually raises my 4 gallon tank of AAA to 120F. Occasionally it takes two heats. The tank stays warm for a good while in all but the coldest weather.

Thanks guys - I love this sub-forum! Earlier I took a piece of scrap knife steel and rigged it up so I could heat it and then immerse it in the tank but after I read Stacy's post I found an old pickup truck kingpin, welded a piece of metal electric fence post to it and now I have two solutions to the problem.
Click to expand...
 
Stacy E. Apelt - Bladesmith said:
Note:
Parks #50 works best at 70-80F. It should not be heated above 90F for best results. In the hot summer, 100F will still work most of the time, but you can chill it with a frozen plastic water bottle on a string lowered in the tank and pulled up and down. If the tank is below 60F, warm it a bit before use.
Click to expand...

Stacey I had read a post that Kevin Cashen posted, I believe it was on the ABS forum, where he said he found a "sweet spot" with Parks50 @ 108 degrees. He said it made the oil "scary fast." Any hotter was too hot and lower made it "slower"
What's you thought on this? I was thinking maybe quenching 1095 with this oil temp to help beat the nose. I don't know a ton of metallurgy but when that guy talks I listen!
 
I also remember that advice of 108 °F for parks...i wish i could offer a first hand advice, but that USA oil is still an unicorn for my far far away land ;)
 
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