12-14-2015, 09:50 PM
WAY before. Blue is 575ºF, orange is 1700ºF.
The idea is to heat the weld to 1400ºF-1500ºF (bright or cherry red) to anneal it so it doesn't break while grinding. Grinding will re-harden the blade, so it needs to be tempered to 550ºF (blue) to make the welded area the same hardness as the rest of the blade. Otherwise the weld will harden even more as it flexes and ultimately break. Be careful to not go too far when tempering. It will go to straw, to brown to purple to blue, and it goes fast.
Tom
The idea is to heat the weld to 1400ºF-1500ºF (bright or cherry red) to anneal it so it doesn't break while grinding. Grinding will re-harden the blade, so it needs to be tempered to 550ºF (blue) to make the welded area the same hardness as the rest of the blade. Otherwise the weld will harden even more as it flexes and ultimately break. Be careful to not go too far when tempering. It will go to straw, to brown to purple to blue, and it goes fast.
Tom
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