Ice block tempering

H

hodgescl

Joined
Oct 8, 2009
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Im thinking about taking a completely hardened blade and freezing it edge down in a tray of ice, then using a torch to temper the spine, while the edge stays nice and cool in the ice,

i just thought of this about five minuts ago so if you can think of anything bad that this could cause.

take it easy, hodges
 
I don't see why it shouldn't work other than you'd have to use a non air hardening steel definitely. Don't be surprised though if it still manages to heat up more of the blade than you want because ice and water can only absorb so much heat.
 
Water freezes at 32F, water boils at 212F. Unless you can heat the spine very quickly (i.e. thin blade) then you'll likely boil off the water.

There are other proven methods out there for tempering. Any particular reason you feel the need to experiment?
 
A common method for differential tempering the spine is to put the edge in wet sand and then carefully with a torch heating the spine till it is a dark blue to black the sand acts as a heat sink.
 
A cake pan with 1cm of water in it will work as well or better than any of the methods mentioned.

The sand will inhibit circulation of water and the ice will allow the water to boil off plus you will not be able to protect the tip unless you tilt the blade as if you were using a cake pan of water.
 
sounds good except the only problem i see is that you would lickley get an incomplete temper, and it would not completly releive internal stresses
 
No real need for ice here. Many makers draw back the temper more fully in the handle and spine, but you always need to temper the entire blade after hardening to reduce stress.

Once you accomplished your initial temper (at, say, 400F in an oven), then you could draw back temper even further for the handle and spine with a torch. No need for ice, though, and you'll find that as the ice melts, you don't have anything in contact with the blade. I just use a large bucket of water and a pair of vice clamps I attach to the side. I position the blade so the cutting edge and tip are submersed, and I start at the butt of the handle with the torch and walk the color (oxidation colors, not glowing) up towards the ricasso and down the spine. If the water starts to bubble around my blade at water line, I agitate the water or let the blade cool a bit before continuing.

--nathan
 
Burt Foster taught me his method. He places 1/4" of water in a cookie sheet. He places the tempered blade in the pan and uses a torch to heat the spine. As the temper colors walk down, he rocks the blade back and forth,from tip to ricasso, keeping th edge cool. Once the spine is drawn to the desired temper ( usually blue) he just tips the blade over sideways and lets it cool in the pan. Simple, easy, reliable, repeatable.
Stacy
 
that makes sense, i guess i was just thinkin too much. i might do it for sh!ts and giggles if i end up with an extra blade. thanks for the input, and have a good one.
 
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