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Time for a proper quencing bucket


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If you are running a major production operation and need to circulate the quench medium to keep it at an even temp or remove the vapor pockets, (like this) I can see running a recirculation pump on the quench tank.

Doing a couple of blades in a sizable quench tank in the garage probably not so much

Edited by Joshua States
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I'm just not sure that the problems associated with industrial quenching in 6000 gallon tanks apply to backyard blacksmiths.

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I took a class at Arnon Kartmazov's shop in Portland last year.  His quench tank is horizontal, but at least a foot deep (sorry I don't remember the exact dimensions).  He uses a small variable speed motor driven propeller (like something from a toy boat) to circulate the oil in his tank in a pretty even fashion.  Works well for him.

 

Josh, you are certainly welcome to agitate your quench tank in any fashion you like.  I find that a fish tank bubbler would produce enough bubbles in the fluid to make me uncomfortable with the potential speed of quench on in discrete locations the blades I make, so I brought it up as a potential issue.  Personally I just stir the oil a bit before I quench, then move my blade in a cutting or stabbing orientation while quenching.

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43 minutes ago, Joshua States said:

I'm just not sure that the problems associated with industrial quenching in 6000 gallon tanks apply to backyard blacksmiths.

 

Sure they do, just not to the same degree.  Possibly even a small enough degree that they could be tolerated/ignored.  I would be MUCH more concerned with agitation in a water quench than in oil.  When quenching a knife or two in a small tank of oil in a home shop would probably not benefit from agitation, assuming the oil to metal ratio was correct.  I don't agitate the oil in my small knife quench tank (aka: bread loaf pan).  Water on the other hand makes a vapor jacket much more readily and could certainly interfere with proper cooling.  This is most readily applicable to alloys that auto-hamon in a water quench.  When you are dancing around the limit like that, small changes make noticeable results (wavy/wispy hamon lines on an otherwise symmetric blade, for example).  In general, I wouldn't worry about agitation at all unless I ran into problems that I could trace back to uneven cooling.  

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Thank you Jerrod. I think that sometimes people fail to consider this:

25 minutes ago, Jerrod Miller said:

Sure they do, just not to the same degree.  Possibly even a small enough degree that they could be tolerated/ignored.

Then they think that if A holds true in a certain application, it must hold true in all applications. That's a slippery slope that often has us chasing ghosts.

 

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This goes well with my stance (also shared by others, I'm sure) that much of what custom makers stress about is well above and beyond what most users will ever need or notice.  Do you really need to get 100% out of your given steel in heat treat?  Probably not.  If you get 90% out of it, will you likely exceed any commercial knife?  Probably.  I think it is great to try our best at nailing everything as well as possible.  But it really should be tempered with being practical.  

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I use a temp controlled electric furnace for heat treating. Quenching 4 knives at a time is doable in my horizontal iron tank, but if I'm doing that I'm pulling them all out and dropping them fully in the tank at the same time. That way they all experience basically the same thing. For sensitive steel like W2, the temperature of the quench oil (Parks 50) can make a difference. If you do 3 or 4 in sequence, the ones going into the hot oil are going to be a little different from the ones going into the not-so hot oil. Also if the oil is smoking, that smoke can catch fire.

I don't move my tank, it's always close enough to the electric furnace that I can get the blade in the oil without f-ing up. 

I have 10 gallons of oil in my tank. I've done vertical tanks with less volume and they worked fine. 

 

Maybe a really big .50 cal ammo can will have enough volume for a few blades at a time, but I'm not sure. 

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  • 1 month later...

I was looking for something deeper than the coffee can i was using. I thought about using one of my ammo cans but instead I found a hollow gatepost with a welded base at either lowes or home depot. it's not super wide but I cut it @ 24in and it works well. When I learn to weld I may make one that is wider. 

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1 hour ago, Al Dolney said:

First time I used that, I'd drop it right to the bottom!

 

You do have to learn not to flinch when the oil goes FOOM! :lol:

 

This is also one of the few times a magnet on a stick is handy.  

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  • 3 weeks later...
On 6/16/2020 at 12:20 PM, Alan Longmire said:

I'd rather have this one for most of what I do: https://colemans.com/mortar-ammo-can-m120-m121

 

 

That would be perfect Alan! And $9.95, what a bargain. They are unfortunately out of stock. I've been thinking about moving away from getting five gallons of the Maxim's #50 quenchant (Parks 50 from what I understand) and want a container large enough to completely submerge blades (and the ends of my tongs if I allowed them to get hot too) to prevent flare ups. 

 

In my mind this is the other component of this thread when considering quenching containers. From everything I have researched, the properties of commercial quenchants (the properties you are paying big bucks for, they are fast initially to get past the nose and then slow cooling as the temperature drops) will degrade if they are allowed to burn which is why complete submersion in them is optimal. I understand they will last for many years if kept free of contaminants and not allowed to flash/burn. Hence the bigger container.

 

If using simple veggie oils or canola probably not as important though bigger may better, but since these oils begin degrading with every use after the first one you'll be replacing them fairly frequently anyway. Might be better to use a smaller container and buy new oil frequently?

 

In any case I definitely need to upgrade my set up, one is a large stock pot for canola oil that I built an immersion heater for and the other is a large turkey fryer I used with peanut oil for marquenching experiments. I have been trying to get my shop cleaned out and set up again and I have many gallons of very old nasty oil I need to dispose of, lol.

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I made a big quench tank which I will use again on occasion, but mostly I'm back to baking pans.

 

I use a cheap multimeter with thermometer to check the oil temp, if it gets a bit high I just add some more cold oil......never treat more than 3 or 4 blades at a time so that works well enough.

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