Your Dry Ice Set Up

colu41

colu41

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Dec 24, 2014
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For those of you who use dry ice treaments for your stainless, how is yours setup? Ive been having problems with my thinner blades. Mainly the .07" AEBL I use for fillets and kitchen sets. I heat treat prior to grinding to keep the steel nice and flat for plate quench. After quench, the blades are as straight as they could be. But after them being in a dry ice and acetone mix for a few hours, they come out warped. I lay the blades flat in the container, throw the 3 lbs of powdered dry ice on top, then pour the acetone in until its about a half inch deep.
Now I've read of some instances where if the dry ice is only on one side of the blade, that it will cool that side quicker and warp it but, being such thin steel, I'm not sure if that would affect it. Any tips, pics or ideas to try and prevent this in the future?
Being powdered ice that I get here locally, maybe make a layer of ice on the bottom of the containter, lay the blades on top, and then sandwich them between the dry ice before adding the acetone?
 
Corey - I purchased a drink cooler similar to this one: https://www.amazon.com/dp/B00363V3LS/

Cost was around $7 or so at a local store. That way I could look and measure depth. It's around 12" or so deep. I did cut a round aluminum disk to place in bottom (first one I punched a hole thru liner while pushing blade in).

I fill container with busted up dry ice (wish I could get powdered DI here), then fill with denatured alcohol. I do have a temperature probe inserted just to see temp. This setup will hold DI mixture at -95ºF range for a few hours. After plate quench, I push blade vertically into DI mixture with a wire (coat hanger, welding rod, etc) thru a hole in tang. This holds blade vertical in mixture for DI treatment. So far, I've not had any problem with warped blades. Before when trying to use a container and laying blades flat in mixture I had several blades come out warped.

Ken H>
 
Oh, that cold on one side more than the other, even for a short time, will affect AEB-L. That stuff will warp 100% of the time if you give it a slight excuse, and many times even if you don't.

I'd go vertical with your dry ice bath. That's what I do, and even then I get some warp here and there. That's even after plate quenching un-beveled blades.

You'll use a bit more dry ice for a vertical bath, but not a whole lot if you size your tank efficiently. I try to only buy dry ice when I have a batch of blades to process, say four chef knives, and that's how my tank is sized. I think it's 2.5x5x18". I just welded up up from some large castoff rectangle-tube end. I surrounded it with 1" foam board that my kiln came packed in.
 
For AEB-L there is supposedly no reason to leave it in the dry ice for any longer than what it takes to equalize the temperature.
 
Ill have to set something up and try the vertical. And usually, when I use 3 lbs of dry ice, Ill take them out as soon as the ice is about 80-90% evaporated which I'm not sure exactly how long but can't be more than 2 hours.
 
would putting them between your quench plates and then in the DI bath be advisable? After quenching of course, out of the foil. Just to keep them clamped. I'm thinking it would be fine, since the plates are going to do a good job of heat transfer.
 
It would take a LOTS more/larger setup for using quench plates. You'd put 1 or 2 or 4 blades as required clamped with the same set of quench plates. I'm sure that would work just fine, as long as the Dry Ice bath was large enough to fully cover the quench plates.

Ken H>
 
Ken H> said:
It would take a LOTS more/larger setup for using quench plates. You'd put 1 or 2 or 4 blades as required clamped with the same set of quench plates. I'm sure that would work just fine, as long as the Dry Ice bath was large enough to fully cover the quench plates.

Ken H>
Click to expand...

I figured it would take a larger container, but in theory, not much more DI. Since the plates take up room in the container. You would just want a container that didn't have too much room around the plates. I think a side benefit would be the plates would pull heat evenly from the blades regardless of the DI distribution. I'm not even sure you would need to cover them, since the plates would get to the temp and likewise the blades as long as the DI is pulling heat from them.
 
I'm thinking about making some thinner plates, say 1/4" mild steel, with bolt-up corners like mokume torque plates, to transfer groups of blades into from the quench plates, to go into dry ice. I may try to make a set of thin steel plates for my 8" chef knives, try 4 at a time, and see how that goes.
 
Salem already said it, but I used to lay my blades flat, and I get much better results with a vertical setup. Sometimes I get a little potato chip effect on an almost-finished chef knife (.110 AEB) if the bevels are ground real fine, but rarely on the .070, which gets ground post HT.
AEB is looking for an excuse to warp- any time it's cold on one side and not the other, there it goes.

Have any of you measured the temp with alcohol/DI slurry?
I don't have a thermometer that goes that low, but I'm curious if anyone has actually checked it.
 
I have an IR thermometer that goes down to -65° And it errors out when I check the temp. So not sure the exact temp, but it's at least -70°
 
As I mentioned in first post my DI mixture normally holds in the -95ºF range - sometimes getting to -100ºF if it's a really good slushy mixture. I use a thermocouple probe for monitoring.

Ken H>
 
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