Quench tank

BD Blades

Well-Known Member
I probably should have thought of asking this a long time ago, but here is my question. I have a small shop and use differnt size baking pans to quench my blades. They hold from about a quart to about half gallon. What would be a minimum recommended size/volume. The amout of oil would surely have something to do with the rate of cooling and hardening. Also what problems would I encounter using too little oil. I have not been getting the edge holding I want from the 5160 I have been using. I know there are a million variables beside the quech volume, but give it you best shot.
 
If you intent is to only quench one or two SMALL blades at a time, you can get away with about 1/2 gallon. Personally, I choose to have at least two gallons of fluid in my quench tank....even then, if I am quenching bowie sized blades, there are time when I must allow the fluid to "cool down" before doing any more quenching.

Here's the deal....IF the quench reaches 180F or more, then it will not cool the steel fast enough to achieve full hardening.
 
BD, one word- “agitation”. Many bladesmiths ignore it but with simple steels it can be critical to full hardness and with any steel it can be invaluable in preventing distortion. Nowhere in industry do important parts just set still in unmoving quenchant, but I often see knifemakers do it. What I am saying is that you will need enough oil, and room in the container, to at least move your blade in a quick slicing or stabbing motion through the quench, thus it is almost impossible to have too much quenchant volume. Couple this with what Ed said about oil temperature and a couple of gallons may work for small blades, but I personally like between up to 5 for bowies and the like, but too many of mine are swords, so I have a bit more yet.
 
What type of pump is best for agitating the quenchant?

Darrin,
I had this idea a while back when I was talking with Lee Neves at Maxim Oil, using a pump with a holding tank would have cooler oil entering the quench tank all the time, it would take a lot of oil to do it this way, this is a theory of course, I think a Little Giant trash type pump would work, I don't think it has to move a lot of oil per hour, just on a continuous basis, you would want the return from the quench tank higher, taking the hotter oil away and the cooler oil entering lower into the quench tank. Again that is theory. In thinking about it, you might need a pump that is going to move more oil faster, because of the time needed to cool the blade down and how fast it cools down, if the oil isn't being exchanged fast enough it wouldn't make a huge difference on an individual blade, it should help with quenching several knives at a time. Until I need to quench a lot of knives at a time on a continuous basis the cost isn't justifiable. It would probably take close to 10 gallons of quench oil, with I'm guessing about a 1" pipe exiting and entering. It's an intriguing idea, just too expensive for me to experiment with right now. Rex
 
As soon as the summer is over and the weather cools off I'm going to start a new quench tank project. I plan on building 2 tanks side by side (one for each type of oil). My plans are to have a way to heat and circulate each tank individually.
 
Thanks for all the great info.

Your Welcome, BD! What makes Knife Dogs so awesome, is that any newby, or anyone else, can get on here, ask a single, simple question. And look at what all happened, several knife makers will now learn something new about their quench tanks, and may build a recirculating quench tank, or some sort of their own variation/experiment/invention, simply because you asked a question. Because ideas were exchanged, people got inspired to experiment with this idea that has a good possibility at improving the quality of our knives. That is so awesome peop.....err,... I mean DAWGS!!!! A perfect example of how to make the world a better place!!!! And look at the people/Knifemakers that responded, some great knife makers in their own right, a Mastersmith that is almost predictable, simply because he (has) to love helping people, that is Ed C. "The Montana Bladesmith", I'm literally in awe of this group!!! Y'all have wonderful afternoon, Rex
 
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I have yet to try this, but i have been told that computer fans can be submerged permanently to create circulation in your quench tank. Best part is they are dirt cheap!
 
I use the valve cover off a Chevy racing engine for a quench tank. I holds about a gallon and a half. There is no oil filler hole in this one and it works great for me. A friend that used to own a garage gave it to me about ten years ago
 
Tom, that's an awesome idea! I've been wanting to upgrade from my ammo can tank to something that will give me more room to agitate some boning/meat prep blades I've been asked to make that are a little longer and thinner than what I generally fool with. Thanks for the tip!

Todd
 
Tom, that's an awesome idea! I've been wanting to upgrade from my ammo can tank to something that will give me more room to agitate some boning/meat prep blades I've been asked to make that are a little longer and thinner than what I generally fool with. Thanks for the tip!

Todd
 
I happened to find a turkey fryer setup on sale for $25 at a local Lowes. 5 gallons of quenchant, has a thermometer built in and I can use the burner to heat the quenchant, brine in this case.
 
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