Welding technique

Victor Creazzi

King of Bondo
Saw a very good demo by Steve Rollert at the RMS meet where he was using mild steel 'pressure plates' with stainless foil as a resist.

I would try to explain more, but it was a 5 hour demo, and to be honest it took me a few hours to start really getting it.

Steve specializes is 'dry' fluxless forge welding for his pattern welded knives.
 

Bruno

Administrator
Staff member
I have heard about dry fluxless welding. Is there any benefit to it? Other than the practical aspect of forge lining etc?
 

Victor Creazzi

King of Bondo
I got to the demo about a half hour late, but asking the same question to others, I did not want to interrupt the speaker to ask about things that had already been covered while I was being late, they were saying that micrographs had shown cleaner welds when done fluxless. I think I'll still be using flux, but there were several things that he demoed that would apply with or without flux. I learned a lot.
 

cangooner

New Member
Have you guys tried kerosene? Clean your parts as per usual, dunk in kerosene (obviously when still cold), then into the forge. As I understand it the kerosene burns away leaving a super thin layer of carbon which protects from oxidation but then is absorbed when welded. I've tried is a couple of times and have had pretty good results. A big advantage is of course no damage to the forge. Curious what others think.
 

Victor Creazzi

King of Bondo
Steve had been using kerosene and that is part of what led him to 'dry' welding. He did also demo a type of canister welding with kerosene. On the 'dry' welded billet he was drawing the billet the hard way on the very next heat, demonstrating that the weld was sound.
 

Mike Blue

Member
If there's no fire, no eyebrows or nose hairs lost...all the hair above the glove line around your forearm...what's the point? This is an unsafe avocation. I'd like to see it stay that way.
 
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Mike Blue

Member
There can be numerous discussions about the stuff that creeps into pattern welded materials from the steel preparation process. This is about how to eliminate flux and the leftover borax or other secret ingredients in someone's home made super weld powder. But we could discuss how descaling rust from steel , or descaling scale from in between layers in a hot weld will leave behind silicates or abrasive grit. All of those can cause an inclusion. If you make steel and leave any kind of inclusion that only shows up when you're just about done with our blade, then you're obviously prone to making your own mistakes. You will be a wise smith in about 50 years when all the young guys ask these questions all over again.

One of the best smiths I know simply keeps all his shim stock in old ammunition cans with kerosene poured over. The principle is that none of the new steel ever rusts. Sure the kerosene burns off but in a reducing fire it's mostly lost to the atmosphere and there just isn't a lot of kerosene in between 0.060 inch thick layers unless it's distorted mechanically.

The overriding principle behind a fluxless weld is "intimate contact." Stack up 25 layers of 0.060 thick materials that are flat/straight to begin and there are no gaps that need to be closed. The liquidus layer that forms at welding heat does not have a gap to leap across to begin the weld. I've seen and had billet soaking in a proper fire that welded themselves. With intimate contact and clean surfaces it is possible to weld at below the "approved" welding temperatures.

The second principle behind a fluxless weld is an oxygen free weld boundary. A lot of smiths will build a "can" around the billet using mild steels. This is the place for used stainless steel heat treating foil. You lot who want an electric heat treatment oven will produce volumes of this stuff. Don't throw it out because it has a second life. Wrap the billet in the approved foil, weld a can around it, or stuff it all into a tube. As the can heats any burnable (maybe a few ml of kerosene?) will consume the oxygen as it burns away. Leave a small pin hole so the pressure doesn't build up and you can watch a cute little flame until all the burnable is consumed then it stops and you know the internal can environment is oxygen free.

The used HT foil is an oxidized surface that will not weld to the can or the billet and that makes it a lot easier to shear the can away from the billet. Or, like some, you simply fold the can material into the billet and have a miserable excuse for a half good billet when you're done.

Nothing is written until you write it yourself. Take good notes. It's really scary when you hear a good idea and then find you wrote it down twenty years ago.
 

verndahl

AKA tintin
I've read that if you don't have a welder you can "fasten'' the stack together with stainless wire. Has any one done this? I so, how exactly?
 

cangooner

New Member
I had some success with that the one time I tried it. Basically make your stack, clamp it or put it in a vise to compress the stack (but do that in such a way that you can still get to at least some of the billet), then wrap the stack with wire. The key though is that you have to get the wire TIGHT. So I did a loop or two, twisted the wire ends together to hold them in place, cut the excess wire, then twisted the hell out of the twisted wire with pliers. That will squeeze the stack close together. Then repeat, move the clamp or vise, and keep repeating until the whole thing is secure. The trick for me was finding the right tension in the wires: too loose and it's sloppy, too tight and the wire can snap.

As I mentioned it worked for me the one time I tried it, but because tacking the ends with a welder is so much easier, I've still only done it that way once.
 

Mike Blue

Member
I agree with cangooner. Eventually you might want a welder. I made do with a simple MIG that was 110v. I'd not do that again. 220v or better if you can afford it. I use flux cored wire. All I want is a tack scab not a perfect bead. By the time I'm done welding, the weld wire is gone as scaled and does not contaminate the pattern underneath.

I've included a picture of the worst sort of billet to lay up. Bike chain is an obligatory exercise. If you get an inclusion free billet and it's pretty, great. Remember if it looks good before you weld it...you will find out exactly what distortion from metal movement will do to any great idea. You must learn to think three moves ahead of where the steel will go. That also depends on what tools you have to move the metal.

But, there are a lot of smiths who cannot afford, or will not work with, a welder. As CG says, it must be tight. The wire will loosen during the warm up. Can you tighten it again while it's hot? The wire will scale away because it's thin, then you can't tighten anything. It's only meant to hold the billet until you can get that first laminate weld done. After that you probably will grind it away. You don't want a weird steel in the middle of the layers somewhere (or maybe you will). I know one smith who used nickel wire and just folded it all into the billet. He makes very pretty steels too.

I'd recommend simple iron wire (plumber's or farmer's rancher's supply, stuff that gets rusty). It won't add any weird alloying elements that some special purpose welding wire could. Minor alloying elements (read parts per million) sometimes give you the fits later. I was gifted a bunch of two inch wide band saw blade. It's perfect, thin 0.062 inch, cuts and stacks easily, good intimate contact (read earlier), clean, 0.06% carbon. Until I welded it into a stack and could not cut that billet with anything except a big abrasive blade and it fought the abrasives. That one went right into the scrap bucket. More chemistry research and the very ends of the cutting teeth had a microscopic bit of cobalt welded on them. If you're going to use stuff like that you have to expect delays. It's more work. I grind off the tips of any cutting tooth now. Better to use known materials with known (acceptable) chemistry. It's just not worth making up for mistakes.
 

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verndahl

AKA tintin
That's good to know as i have plenty of that kind of wire. I'm a long way from trying any kind of welding (though i don't know how long i'll be able to wait 'till i just have to give it a try). Always fun to dream of what i hope to do someday. Is it advisable to use flux for a first attempt or might i be successful with a simple dip in kerosene?
 

Mike Blue

Member
Flux. It's more forgiving. Buy some Twenty Mule Team Borax at the grocer. Spread some over an old cookie sheet and bake in the oven at 230F for a couple hours. You want to dehydrate the borax by cooking off the water. Keep it in an airtight container after that as it is hygroscopic and can absorb moisture from humid air.
 
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