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Originally Posted by T. Hendrickson
I feel like I know just what my mistakes were and how to avoid repeating them in the future.
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Yep, but there are plenty of new ones to make Thayer!
Sorry for not getting back on the repair deal. Computer crashed. Just got a chance to get back on.
I had a feeling that is what happened. It's all to common. Got one to fix myself that I broke driving on a bolster. Read through the rest of the post after your question and didn't see it answered so I'll take a shot. I'm no blade smith either. I just do what works.
Yep, arch welding is the easiest way. I'd notch the steel at 45 degrees or so on the sides to about 1/3 of the way deep. Leave the top and bottom of where the tang and blade meet as is. I use a dremel with diamond bits to do it.
The object is to get a notch on both sides that follows the crack and leaves a 1/4 or 1/3 of the thickness in tact in the center to index the joint back together. And keep the weld from blowing through to the other side.
Then clamp the two parts together on something that won't burn and heat the area around the joint till it's at least 450-500 degrees. I think actual procedure for 1095 might call for 850, but I've not had to go that high on the few I've done and had no failures. Use the smallest stick you can and the lowest setting that will weld without sticking.
I know. That's not what your taught. Your taught to get good penetration. And you do want penetration, but if it's too hot it will cut the original steel around the weld and leave dimples you can't get out with sanding. So at least on the final passes you just want it to stick more than penetrate.
Run a bead on one face and let it cool while clamped down. Turn it over, clamp it back down and repeat the procedure. Let it cool and then clean ALL the slag out. You may have to resort to the dremel to get it done. Repeat the procedure until the weld notch is filled above the original metal.
Oh, and use the welder to put that radius in where the tang and blade meet so it doesn't happen again. And use at least a 7018 rod. and there are some better rods for hardenable/tool steel if you can find them.
Now just grind it back to original profile and re heat treat. This time, don't harden the whole blade and leave the tang and spine softer/tougher using some of the info you've gleaned here. Should be fine.
I'm sure there's some welding engineer reading this thinking, "You dumb A, that won't work. You have to do...!" And they may be right. But as I said, I've used this procedure a couple times and after a some failed attempts they are in use today.
Hope this helps.
chiger,