Dry Ice and Acetone

I am told that dry ice and isopropyl alcohol will get down to about the same temperature, and is less smelly and a bit safer.

Use this link to search BladeForums with google, for me it works better than the search function on-site. You will find lots of interesting threads about dry ice being used to complete the quenching process and convert retained austenite.
 
I use dry ice and low odor mineral spirits. Less flammable and evaporates slower. BAsically you just need to use a liquid that won't freeze at -100F.
Chip Kunkle
 
mineral oil also better because it wont dissolve atmospheric water. IPA and Acetone both turn into a sluch because of all the water frozen in it. Don't ask me how I know.... ;)
 
well in the vein of cold things, maybe you could quench in my ex wifes heart, I think it hovers just off of absolute zero...
 
70% isopropanol will not get below -20 F or so. You have to use the sterilizing grade 97%. Its available at the same places 70% is.
 
me2 said:
70% isopropanol will not get below -20 F or so. You have to use the sterilizing grade 97%. Its available at the same places 70% is.
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That's very good to know, thank you. I have some access to tech-grade chemicals that are much less watered-down than consumer stuff, but most folks don't.
 
I learned the hard way. Spent an hour waiting for it to cool for some charpy impact samples. Specs had the test at -40 C. The mix got to -20 and started slushing up and wasn't getting any colder. Got the 97% and it didnt even slush up. 200 to 300 ft-lbs at -40. Toughest steel I've ever seen. The 97% is available at any drugstore.
 
I've been using kerosene, because it's what I had. Seems to work pretty well and doesn't slush up.
 
me2 said:
I learned the hard way. Spent an hour waiting for it to cool for some charpy impact samples. Specs had the test at -40 C. The mix got to -20 and started slushing up and wasn't getting any colder. Got the 97% and it didnt even slush up. 200 to 300 ft-lbs at -40. Toughest steel I've ever seen. The 97% is available at any drugstore.
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If you need enough of it to quench in, you can buy methyl alcohol by the gallon in Home Depot paint section much cheaper than by the pint in the Pharmacy.

Methyl Hydrate
Wood Alcohol
Methanol




http://www.homedepot.com/h_d1/N-5yc...splay?langId=-1&storeId=10051&catalogId=10053
 
darrin sanders said:
I've been using denatured alcohol. Anybody know what that goes down to?
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wikipedia indicates the freezing point for 100% ethanol is -114.3. Denatured usually has 4% methanol in it which freezes at -97.8 so the 4% will make it a bit higher.

wikpedia also indicates that dry ice at atmospheric pressure is -109.3 so using a different fluid to get the most out of your dry ice could be in order. You are right on the cusp...
 
I've never understood the need for liquid around the dry ice. A blade placed between two pieces of dry ice will be -114°. That's why the crucible data sheets spec -114°. There is a significant cooling loss as the liquid freezes as seen by Me2's results. There should be no cooling loss when freezing the metal directly. Is there some other benefit to the liquid?

Here's a tip: Hold down the ALT key and type 0176 on your number pad and you will get the degree symbol °
 
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