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+---- Thread: Bandsaw blade welding (/thread-2999.html)
Bandsaw blade welding - Vinny - 12-14-2015
I've got a bandsaw blade welder and have made several blades. Sometimes, however, they break while grinding them smooth. Most of the instructions I've seen say to grind it before annealing it. But I've seen a few that say to grind it after. Which is correct? I've been doing it before and just a few minutes ago I broke it while grinding and I wasn't really flexing it that much. At least no more than usual and probably much less.
RE: Bandsaw blade welding - TomG - 12-14-2015
- Weld it
- Anneal it bright red (not orange)
- Grind it
- Temper it to blue
- If that doesn't work, build my soldering fixture and silver solder it
RE: Bandsaw blade welding - Vinny - 12-14-2015
"Temper it to blue" I've never seen that stage in any of the docs. Tips on how to do it?
RE: Bandsaw blade welding - dallen - 12-14-2015
I would think that after you grind it to put it back in to the welder and heat it until the welded spot turns blue then quench it in oil probably
RE: Bandsaw blade welding - TomG - 12-14-2015
Just heat it with the welder or a torch until it turns blue and call it good.
Tom
RE: Bandsaw blade welding - Vinny - 12-14-2015
Blue is before orange, right?
RE: Bandsaw blade welding - TomG - 12-14-2015
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
RE: Bandsaw blade welding - Highpower - 12-14-2015
Cheat sheet:
![[Image: Temperature-color-chart-large.jpg]](http://www.simplytoolsteel.com/images/Temperature-color-chart-large.jpg)
RE: Bandsaw blade welding - Vinny - 12-15-2015
Ok. Now I got it. I'll putt the saw back out later (the blade's already on it but I haven't used it yet) and hit it with a torch.
Thanks!!
RE: Bandsaw blade welding - TomG - 12-15-2015
You should be able to temper it with the welder, but a torch will work as well.
Tom