Epoxy and Cryogenics

[thknives]

Just to share this with you guys. Glued up a piece of paper micarta to linen micarta with a epoxy called G2 and had it frozen in liquid N. I thought the glue would fail, or become brittle, but not at all. I could not pry the two pc apart. Took the hammer to it and had to wak it twice before it broke and guess where it broke, not at the glue line at all. It broke taking the top layer of the paper micarta off.
Now the cryo guy is going to line his freezers with micarta.

Thomas

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Haslinger Handcrafted Custom Knives
http://members.home.net/thknives
thknives@home.com

 

[totally tactical]

Hi Thomas;

I'll be the first to ask where you do you find G2????

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Scraped, burnt, sliced, smashed. AHHHH, knifemaking!!!!

 

[Jeff Clark]

The quickest way to have a problem is at the junction of two dissimilar materials. When you bond micarta to micarta the thermal stresses are minimised since both halves shrink about the same. If you bond micarta to metal I believe that the micarta will contract more than the metal and stress your epoxy. The epoxy may actually have a higher tensile strength at low temperature, but it will be more brittle and less elastic. I wouldn't epoxy micarta to the inside of my cryo chest. Even if it works at first, you are likely to get failures after repeated cool-down cycles. Likewise I wouldn't rely on just epoxy to attach my knife grip if I planned on cryo treating it after attaching the grips.

 

[thknives]

I have no intentions to cryo my knives after they have handles put on. The only reason the glued up pieces ended up in the freezer, is to do some testing.

Jeff, actually the metal will contract more then the micarta. You are absolutley right that different materials have different expansion/contraction ranges. We have been experimenting with different materials in the cryo, just to see what happens. The fellow will be installing the micarta "free floating" on the inside of the chest. But he will glue the one piece seal of wool on with the epoxy.

The epoxy is avalible at Lee Valley Tools.

Greetings,

Thomas



------------------
Haslinger Handcrafted Custom Knives
http://members.home.net/thknives
thknives@home.com