I’ve been continuing to experiment with welding, and have tried to actually make a few things out of some of the steels I’ve been assembling.
The news is mixed. My super-duper technique for making forge-welded san mai billets is categorically not super-duper. There is something wrong and it’s not working; I continue to experiment and try to figure out what is going on. It could just be a bad idea, but I still think the physics are on my side. The last attempt appears to have failed because water was driven from the furnace cement into the space between the plates, preventing it from welding. “If it wasn’t frustrating, it wouldn’t be worth doing,” is my motto for that particular project. That and, “make haste slowly.” I force myself to remember that 1) if it was easy, everyone would have figured it out, already and 2) it may just not work, which would certainly explain why nobody else has figured it out.
To preserve my sanity I’ve done a couple of other small projects I can succeed at. Results have been mixed.
The forge-gods chose to remind me that “your welds must be clean” – I spent several hours cutting and shaping this blade, quenched and heat-treated it (that part came out great) and then right when I got to the place where I wanted everything to be just right, it appears my weld is bad:
Well, I like the shape, anyway. But it’s not worth any more work. It’d still sharpen and polish up fine, but I’d know it was junk, so that’s unacceptable. That blade was ground from an early experiment in dry-welding and I have been being more careful with my pre-weld cleaning and prep, anyway. So I am hopeful that I can put that painful mistake into the past.
That’s a piece of cable damascus, ready to get welded onto one side of a bar of 1095. I just love the internal structure of the metal, with all the mooshed-up cable bits. It looks like some kind of dragon-skin or something. To get the texture of the metal to come out, I etch it lightly in ferric chloride.
One thing I’ve learned is that WD-40 is an essential ingredient for everything. Since cleaning the surfaces is so important, keeping them from oxidizing before you get them into the forge is crucial; that’s WD-40’s job.
Some forge-welders use kerosene as a flux, but they also use it for long-term storage of billets that are ready to go into the oven. I guess that also helps prevent oxidation. There’s a problem: when you prep-weld your billet with your MIG welder, it’s really hot and it’s oxidizing merrily. That’s when you both want to and don’t want to drop it into kerosene. Timing is everything and it’s all dominated by physical law. I keep begging that an exception be made for me, but it’s not happening.
That’s a chunk that I assembled in a two-stage process. First, I made a small billet of cable damascus (like the one shown above) then cleaned and prepped it and prep-welded it with the MIG to a bar of 1095. I then welded those together, giving me a bar that’s pretty complicated inside. It quenched and tempered just beautifully, and didn’t explode or bend, which is often a problem with bimetal – I think that having hammered the cable damascus flat it hasn’t got much orientation left to try to spring back into. Unlike the little fish knife with the crack on the edge, that’s a very clean weld.
After a few minutes in the chloride you can see the layout of the metal: the black down at the edge is the 1095 at about Rockwell Hardness Scale 60, and the cable is “soft” comparatively, because I differentially quenched it in a clay blanket. There is actually a temper-line and an edge of completely different metal.
I’m trying to decide how to polish it. I can:
- Etch the whole thing heavily and just polish/sharpen the very edge
- Etch the whole thing heavily and polish the entire bevel
- Leave it nice and shiny and let time and sweat and chemistry slowly reveal the inner structure of the metal.