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Quench Tank Ideas

Discussion in 'Forges, Ovens, Kilns, & Salt Pots' started by dancom, Oct 19, 2015.

  1. Brad

    Brad Active Member

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    I think a quench tank is a personal choice. The right answer is what best suits your purpose. There are pros and cons for each
     
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  2. John Noon

    John Noon Well-Known Member

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    If there are any gas bubbles that could reduce the cooling effect then they will be travelling vertically. If vertically quenching then they would reduce the heat transfer from the oil or water to the blade, my take on it anyway.
     
  3. Yamroll

    Yamroll New Member

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    I recently picked up a metal ammo tube from Princess Auto for $25. It's for 105mm cannon shells, 6" x 4', holds about 5 gallons and has a rubber gasket on the lid. Probably overkill, but it has a ton of character, and will let me do longer blades in the future if I choose.
     
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  4. Yamroll

    Yamroll New Member

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    You know, for the ammo tube tank, since I've got extra length, I've been toying with the idea of sticking a water heater element in the bottom for preheating the oil. Anyone tried something like that?
     
  5. dancom

    dancom Dust Maker Best Shop Tool

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    That's what I am doing. I have an engine block heater and thermocouple tied to a temperature controller. For safety I have a 90°C high temperature cut-out disc. Working with a 10 gallon air compressor tank, on wheels of course. :)
    I love my local dump!

    Dan
     
  6. jeff

    jeff New Member

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    I have been thinking of getting a tank welded up 3 inches wide 5 inches high say 30 inches long put 4 inch legs on it then attach a bbq burner right under tank. The bbq burner would attach to a ball valve propane line regulater then propane tank. You could even use black pipe cap one end drill holes along top thread on ball valve and so on.
     
  7. jeff

    jeff New Member

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    almost forgot use a meat thermometer to check the temp
     
  8. Ta2edfreak

    Ta2edfreak New Member

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    I use an ammo can from Princess Auto and yes they should be waterproof unless the gasket is gone, which they shouldnt, coming from the store. You can always replace it though. I heat up a railroad spike and drop that in to heat the oil prior to quenching my blades, just once is usually enough to heat the oil for a couple of blades and of course each blade heats the oil a bit. I used to quench and then leave my blades in the oil until I was done all of them but I noticed I got a lot more warps if I did that, now I quench them and hang them up. I have very few warps now. I did ask on another forum if tempering in a deep fryer would work though. It should as long as the oil isnt old and can get to the temp you need. You need a good thermocouple and control though as deep fryers normally ramp up and down a fair amount.

    I saw that rocket tube as well and almost got it but I was wondering about how much it would need to be modified and what happens if I drop a blade.
     
  9. John Noon

    John Noon Well-Known Member

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    Went with wiping the blades down after quenching then into the oven on the rack. Was really surprised how far off the oven temperature was when I decide to stick in a thermocouple and see what was the actual temperature.

    Ran into a bit of an issue with the pot in that fillet knives wrapped in foil were to long too fit. meant cutting the foil, pulling the blade then quenching. For the first time doing stainless steel it did add in a complication I had not planned on and repeating four times was fun.
    Didn't help having the pot on the floor and the dog trying to lick up the dropped oil. I swear cooking oil is crack to that Collie

    Local Princess Auto wants $50 for a 20mm ammo can which is insane or I have not been keeping up on the price of military scrap.
     
  10. Yamroll

    Yamroll New Member

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    I ordered up a PID controller and SSR today. Going to try sticking a water heater element in my tank.

    Really hoping I can get it hot enough that I can use it for tempering as well. Shall keep you guys posted.
     
  11. dancom

    dancom Dust Maker Best Shop Tool

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    Hey, what controller and probe did you get?
    Mine is a Mypin TA4-SSR. For a quench tank a 400°C probe is okay.
    I had a thought about this before. Ultimately, I questioned... Do I want to heat up 6 gallons of oil (temperature rise & think thermal mass) to temper a blade, when a toaster oven will do the same job for 1/20th power?
    It's an efficiency thing and 100 ways to skin a cat.

    Dan
     
  12. Yamroll

    Yamroll New Member

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    http://www.amazon.ca/dp/B00T2IODGS/ref=pe_386430_126088100_TE_item

    Just a cheapy set up from Amazon. Didn't want to spend too much on something that's pretty much an experiment at this point.

    As far as tempering in there, I agree, it would be wildly inefficient. I've been wanting to make some machetes and what not though, and have concerns about how useful a machete that fits in a toaster oven would be. :D
     
  13. Brad

    Brad Active Member

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    Well don't knock tempering in oil I think Kevin Cashen uses hot oil to temper and heat treat (salt bath for heat treating) The reasoning is once the oil or salt is to temperature then the heat is even no hot spots
     
  14. Grizz Axxemann

    Grizz Axxemann Active Member

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    Molten salt, I presume?
     
  15. John Noon

    John Noon Well-Known Member

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    yes molten salts, used throughout the manufacturing industry for tooling. oil or salts good for small intricately shaped objects
     
  16. Brad

    Brad Active Member

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    Yes molten salt. I did some research on it a while back. Some of the benefits were an oxygen free environment, no scale. The salt bath allows you to have a blade almost finished before heat treating because you have such an even heat. The salt is non toxic so its easy to dispose of and its not harmful while cool.

    The cons are pretty big too. Its very dangerous, get some water in it while its hot and it explodes. Molten salt flying around at 1500 plus degrees is not good. When the salt is hot it makes a very corrosive environment (Here in NS I fight with rust enough without any help). I haven't tried setting up a salt bath yet I might in the future.
     
  17. Yamroll

    Yamroll New Member

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    Oh yeah, don't get me wrong, tempering in oil is a great idea. My thinking (and I'm assuming Dan's as well) is just that heating an uninulated steel tank with 5 gallons of oil in it to 450f for an hour to temper a 4" Loveless drop point hunter doesn't make a ton of sense from a power economy sense.

    The molten salt thing had me wondering about using a molten salt bath inside my forge to treat stainless. I figured it would be easier to control the soak temperature over a longer period if I had the knife sitting in a salt bath, monitored by a thermocouple, just turning the burners off when the temperature gets above 1950F or so, and back on when it drops below 1900. Idea's for another day, haha, I have too many projects on the go already.
     
  18. dancom

    dancom Dust Maker Best Shop Tool

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    Yes, I was referring to the efficiency as Yamroll said. There's obvious merit in oil tempering in terms of uniformity and temperature control. If a special tray or low volume cylinder was used it would make it more practical. For tempering you don't need the volume of oil as you do when quenching.

    The flash point of the oil needs to be considered as well as there are fire risks. These flash points are published on Parks' web site:
    #50 Quench Oil 280°F (138°C)
    AAA Quench Oil 340°F (171°C)

    So tempering below the flash points with these quench oils would be not much use to most knifemakers. Tempering above the published flash point, well...do so at your own risk.

    It's always good to brainstorm ideas, just don't burn the house down. ;)

    Dan
     
  19. Yamroll

    Yamroll New Member

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    Yeah, fire is the other major consideration. The plan is to put it together to heat canola for quenching, and if it turns out the rig is even capable of sustaining higher heats, I'll start looking at different oils.

    I know some silicone hydraulic oils are good to around 500F, I had been knocking the idea of using a low viscosity one for quenching for a while now, but that would all depend on testing individual oils for smoke points and what not.

    One of the beauties of the ammo canister quench tank is it's a heavy steel hinged lid with a little pressure relief valve, so if it does get away from me I can cap it to cut off the oxygen without worrying about turning it into a napalm pressure vessel.
     
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  20. Ta2edfreak

    Ta2edfreak New Member

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    If you're going to temper in oil, why not use a cooking oil that is meant for those temperatures? It will still heat uniformly and any fumes given off wont be toxic. Most vegetable oil flash points are around 450 - 475 and relatively cheap in quantity.
     
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