Rant: my forge welds keep failing on high-carbon billets

I was trying to stack 1095 and 15n20 layers in my shop in Portland last Tuesday, and after 4 hours of hammering every billet delaminated at the edges. The welds held in the center but blew out on the sides every time. Anyone else fought with scale getting trapped between layers on thick stacks?

3 comments

3 Comments

brian_rivera593d ago

Yo, that's a brutal one (I've totally been there). It honestly reminds me of the time I was trying to weld up a 1080 and 15n20 san mai and the whole thing just started peeling apart like a bad sunburn on the edges. I spent like 30 minutes just staring at it thinking "what did I do wrong" while my beer got warm. For me it turned out I was being too aggressive with my hammer blows on the first weld, pushing the flux right out before it could seal the sides. Maybe try a really light touch on the first few passes to get that edge lock, then go ham on the middle.

blairtaylor3d ago

Read an old article by some Japanese smith who claimed the secret was basically "hit it like it's a baby's forehead" for the first three heats. That stuck with me because I was definitely coming down like I was trying to drive fence posts through that first weld. Switched to a lighter hammer, maybe 2 pounds, and focused on tapping the edges first until I saw the flux weep out clean. Then I'd bump up the angle and go harder. Took a few tries to get the feel right but it stopped the peeling. Also started brushing between every heat with a stainless wire wheel, not just when I thought it looked dirty. The Japanese guy said most delams start from invisible scale, not the stuff you can see.

claire_ramirez3d ago

Why do you think the scale is just getting trapped and not being burned into the billet itself? I used to swear by brushing with a wire wheel between heats on stuff like 1095 and 15n20, thought it was the only way to keep things clean. But after wrecking three stacks with the same edge problems you're describing, I realized my flux was drying out too fast on the sides before the hammer even hit. Now I switch to a borax mix that stays wet longer, plus I weld the edges first with a lighter tap before going for the full stack. Total pain in the ass, but it stopped the delams cold for me. Hope that helps, because four hours of wasted hammering sucks.