Cryo question

G

Gossman Knives

Edged Toolmaker
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Apr 9, 2004
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At present time I send my blades out for heat treating and cryo treating. My question is could I cryo treat myself without a large expense? What are the dangers of dealing with liquid nitrogen how should it be handled and stored and is it easily obtainable or should I just stick to having the pros handle it for me? Thanks
Scott
 
I recommend all knife makers do their own heat treating if financially and location possible.

A suitable liquid nitrogen dewar will normally cost several hundred dollars. I spent over $400 for the one I use. To locate the nitrogen for filling the dewar contact local welding shops to see where it is best obtained locally. My 20 liter dewar costs me about $67 to fill and will last me about 4 1/2 months between refills (It depends on the quality of dewar and the amount of material being treated). The cost of LN seems to vary regionally.

RL
 
Scott,

You can do it yourself, but you have to temper again afterwards. So you'll need to know the tempering temperature that the guy doing the treatment used.

For equipment you need a dewar. I bought a 5 liter lab kind. It holds stuff for about 5 days and costs me about $20 to get filled. I also bought a big honker but it is out for service and will probably cost me a fortune to get fixed.

As far as handling, it's not too bad. The guy that delivers the stuff told me a story. Seems someone was pouring from one container to another with gloves on (seems like a good idea). Something slipped and the LN poured into his glove. He lost his entire hand.

Just food for thought.

Steve
 
Thanks for the imput guys. I really want to heat treat myself,(air hardening steels) but at present time it's just not feasable for me to do. Money and space are a consideration right now. I am going to experiment with the torch heat treat on carbon steels. The LN is definately something to ponder :eek:
Scott
 
In the mean time there is always dry ice. It should help.

Remember though, cryogenic treatment is a component of heat treating just as parts such as tempering are. You can heat treat without such components but if they are included they are part of the heat treat and not seperate from that. So, when they HT it is not that they also cryo but rather they HT which includes a cryo.

RL
 
Scott don't listen to Roger!! I was once as you are - happy. Then I listened to Roger about heattreating at home. Arrggghhhh....

Just kidding. Roger was very nice and helpful all thru my learning how to do it. And he was right, it adds a whole new dimension to knife making and fun too. Until you get your own setup, tho. Send your blades to him!

Steve
 
Roger is right, and that's why he found that when hardening and tempering is not done right it negates any effect of cryo.
 
It sounds like the heat treating, tempering and cryo is a whole other art form to learn. I'm buying my equipment a little at a time. I'm trying not to go into debt and take all the fun out of this so I guess I'll be reading up on this other aspect of knifemaking. Thanks guys
Scott
 
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