Dry ice and kerosene

chris609

chris609

Joined
Oct 6, 2003
Messages
274
Hello all, Im getting ready to begin my own heat treating and would like to know if a standard cooler would work for the dry ice and kerosene treatment. Like the plastic type insulated coolers. Any inpute would be apreciated thanks.
 
Based on exactly ONE time that I tried it, I'd have to say yes. I used a regular Igloo insulated plastic cooler. Warning, it will stink up your cooler like kerosene, so either get a dedicated cooler for your kerosene, or be prepared to air it out for 6 months.
 
I've heard about using acetone, though for like 10 years I used denatured alcohol
and dry ice.
Ken.
 
Kerosene will melt the Dry ice faster
Have used Dry Ice and Acetone to good effect
Best way is to get two blocks of dry Ice and Sandwich your blades in between
If you skip the Acetone you can use a cheapo styro cooler with a good lid but it won't last very long overall.
I used a decent cooler bought at Second hand store with a tight fitting lid
Get the right size of your biggest anticipated blade size, no more
Keep your blades in the freezer overnight --- Get the dry Ice --- then do the sub-freeze
Sandwich your blades --- close the lid --- Leave it alone! for at least 12hrs
Mine are done after the Tempering cycle although some will argue the point :D
It does work even on carbon steel to a degree
 
One of my problems is that I left the alcohol in too long before the blade, and the alcohol froze solid before I could get the blade in the slush. Put the blade in first and pour the alcohol in after.
 
I have used odorless mineral spirits. While not exactly odorless, it does have less odor. Put a plastic container like a shoe box from Wally world in a cooler, break dry ice into chunks, pour in the mineral spirits and slide the blade into the slush. I have never had the slush freeze up. Put the can of mineral spirits in the freezer prior to using. Saves on the dry ice. I have found that 2 pounds of dry ice makes enough slush for several blades. If you wrap some insulation around the cooler, it can last for several hours.
Chip Kunkle
 
I found a large cooler at a yard sale for $1. The top hinges were broken, but the lid fit fine. I placed a section of Kaowool in it in a "U" position ( best way to describe it). I placed a metal pan (whole fish cooker from another yard sale) on the wool. Poured denatured alcohol ($10 for a gallon can from Home Depot) in the pan and add the dry ice chunks.
After giving the hardened blades a snap temper at 200F, I had chilled the blades in the freezer and kept them there until ready to place in the alcohol/dry ice mix. After placing the blades in the pan, I folded the wool over the pan and placed the cooler lid on with a brick on the top ( because my cooler wouldn't latch shut). Just leave it and go to bed. The next day all there is is a pan of alcohol with the blades in it. Pour the alcohol back into it's can and label it for "cryo". Give the blades a second temper and a third,because the snap temper really does not count.
 
Thank you all for your input I cant wait to get started. Heat treating has been something I have wanted to do for so long.
 
Is there something that can be used with dry ice that does not evaporate once the ice is gone. I am assuming that the liquid is to evenly distribute the temp over the blade. How about transmission fluid or mineral oil?
 
Patrickknives said:
Is there something that can be used with dry ice that does not evaporate once the ice is gone. I am assuming that the liquid is to evenly distribute the temp over the blade. How about transmission fluid or mineral oil?
Click to expand...

I use acetone in my Dry ice, I just leave the lid on the cooler and have been using the same acetone a few times now. I just pour out the acetone into another container and go fill the cooler up with cubed dry ice and ad it back again. Its all how well the lid on your cooler seals really.


Shawn
 
hey can someone tell me more about this? when this is done does it take the place of heating the metal, or does that still need to be done?
 
This is a "low buck " method of cryogenically treating your steel. Its mostly done with Air-hardening steels to convert any remaining austenite to martensite. You still must heat and quench your blade, this is done afterwards, usually after a snap (low temp) temper. then your remaining temper cycles are done following the cryo.

Shawn
 
Here is a big hint. Don't just dump a bunch of dry ice in a bucket of kerosene. I did and I had kerosene foam all over the shop floor. DUH. I went to kerosene after I got rid of my old acetone when I moved. I do like the old cooler idea. I have been using a metal bucket with isulation taped to the outside.
 
I'm no expert on the subject, so take all this with a grain of salt...

A fair amount of reading suggests strongly that dry ice is sufficient to convert retained austenite into martensite, in low-alloy steels. The same research indicates it won't do much at all for high-alloy steels, because the chromium and other elements make it more resistant to being converted. It seems that much colder temps (liquid nitrogen) are needed for stainless and tool steels, to make a significant difference.

Another thing to keep in mind is that acetone has an interesting capacity for going "WHOOSH" and burning down your shop under the right/wrong conditions. Kerosene is somewhat less likely to do so, and isopropyl alcohol is "safer" still. But all 3 are flammable. I don't know if putting them in solution with dry ice makes any difference.

Your homeowner's/renter's insurance agent, and local fire marshall will probably have a strong opinion on all this. There's a reason factories are required to keep volatile solvents like acetone in grounded cabinets, and folks generally don't use kerosene lamps anymore.

Not to rain on anyone's parade, but I've become a big believer in letting experienced professionals with serious equipment do my HT, tempering, and cryo-treating for me.
I'm not saying dry ice won't help, but I am certain that firms like Paul Bos and Peters' HT do a better job than I can do in my garage with a kiln and an old cooler. When you start crunching the numbers, it's mighty difficult to compete with them on a cost-per-blade basis, as well.
 
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Each to there own, but, having a digitally controlled oven and a RC tester I do know that a dry ice bath will get me anther point of hardness with D2 which is 12% chrome. Ask Nathan the Machinist about his experince with a professional HT and D2. Some of us just like to do as much as we can ourselves. The cost is not always the point. Like some say "you can by a perfectly good knife for a lot less than a custom".

On the fire issue. I do keep my cumbustables in a metal cabinet outside the shop. By the way finishing oils are also very cumbustable and some are pryrophoric. We all work and keep around stuff far more cumbustable than kerosene. Go throw some corn starch in a flame. I would rather have a can of kerosene on my place than a lawn mower with a tank of gas.
 
Does anyone have experience with LN2? I have been told that what is really needed is a slush. Thanks,bullet
 
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