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NO FLUX WELDING


Gary Mulkey

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. So that means this works only with relatively low carbon/alloy steels which allow welding at high temperatures I presume?

 

The thing I also considered, though that effect might be less important is that iron burning on the outside of the stack would remove oxygen from the air before it enters between the layers? So that heavy oxidization on the outside may actually help protecting the metal deeper inside. This would only work if the openings between the layers are sufficiently small.

While the books say 1369C, I don't think my forge has ever been that hot.

 

My experience is mostly with low carbon steel. On burning, except for light surface burning, I've found once you've burned it, you've burned it all the way through.

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I find this all interesting.

welding without flux is the standard british way of forge welding but it normally involves a temperature that exceeds the workable temp of carbon steel ie a sparking heat .

and this would be a standard way of welding in an axe bit sparking heat , with the bit protected by the mild outer and no flux.

In my experience its not the high temp that messes up carbon steel but the oxidising anyway , in a hot reducing atmosphere you will get melting and not burn .

I have had people successfully do this at my first forge in, welding a stack in a gas forge without borax because they did not see that stage (ignorance can be power), they went on to make knives from the damascus that seemed just fine.

so I am keen.

are we talking press or power hammer here.

forging soul in to steel

 

owenbush.co.uk

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While the books say 1369C, I don't think my forge has ever been that hot.

 

My experience is mostly with low carbon steel. On burning, except for light surface burning, I've found once you've burned it, you've burned it all the way through.

 

Thanks! That's the great thing of talking to people with lots more experience: this saves me from having to figure this out with lots of trial and error :)

Jeroen Zuiderwijk

Facebook page: https://www.facebook.com/barbarianmetalworking

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It works on big billets too!

 

Even with a looong soak to get this big guy up to heat it welded just fine.

 

photo(1).JPG

 

It may be my imagination, but the welds actually seem *stronger* this way. After just one weld pass I was able to compress on the edge with no weld failures.

 

This is so friggin' awesome. I'm hanging up my 7" grinder. Woo hoo!

 

--Dave

 

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"It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood, who strives valiantly; who errs and comes short again and again; because there is not effort without error and shortcomings; but who does actually strive to do the deed; who knows the great enthusiasm, the great devotion, who spends himself in a worthy cause, who at the best knows in the end the triumph of high achievement and who at the worst, if he fails, at least he fails while daring greatly." -- Theodore Roosevelt

http://stephensforge.com

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gonna try this next week - will it work with welds that are longer than the fire box of the forge? my main forge is a fogg style vertical, with about a 6" internal diameter, and most of my welds are 10" butt welds - i've mostly seen flux as a way to protect the steel in the dragons breath, more than the area i'm bringing up to welding temp. but if i understand this, as long as i only work the area in that's fully up to temp, when i heat the next section the scale should convert back to steel?

Jake Cleland - Skye Knives

www.knifemaker.co.uk

"We can't solve problems by using the same kind of thinking we used when we created them."

"Everything should be made as simple as possible, but not simpler."

"Two things are infinite: the universe and human stupidity; and I'm not sure about the the universe."

 

Albert Einstein

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I've just experimented with this shortly so I'm still learning but something that I have noticed so far is that the ends of the billet seem more reluctant to weld than with flux. I have gotten them to weld but only after a little more work.

 

Has anyone else noticed any differences in the ease of welding this way?

 

Gary

Gary

 

ABS,CKCA,ABKA,KGA

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I've just experimented with this shortly so I'm still learning but something that I have noticed so far is that the ends of the billet seem more reluctant to weld than with flux. I have gotten them to weld but only after a little more work.

 

Has anyone else noticed any differences in the ease of welding this way?

 

Gary

 

I've tried it three times now, and they all seemed to weld pretty easily and uniformly. I am setting the welds with the press, however, which I think is an advantage with this method of welding (i.e. no flux to drive out between layers, so uniform pressure is okay instead of risking trapping pockets of flux).

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"It is not the critic who counts; not the man who points out how the strong man stumbles, or where the doer of deeds could have done them better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood, who strives valiantly; who errs and comes short again and again; because there is not effort without error and shortcomings; but who does actually strive to do the deed; who knows the great enthusiasm, the great devotion, who spends himself in a worthy cause, who at the best knows in the end the triumph of high achievement and who at the worst, if he fails, at least he fails while daring greatly." -- Theodore Roosevelt

http://stephensforge.com

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Anyone doing this sans mig welder? I've an arc welder, but don't use it on billets for the sake of avoiding having to grind the weld material away.

 

I usually wire-wrap my billets and forego the handle as well, using tongs- welding 12" billets in an 8" interior space upright forced air forge, taking several heats to do so.

 

I'm guessing that's a lot of strikes. ;)

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Gary, I have also had some problems early on with billet ends, now I heat the end of the fold slightly higher than at the hinge, so it is still at welding temperature, when I work my way back to it.

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I have weld modern steel´s carbon and stainless whit out flux, but I have mig weld whole billet so all layers are

shut...This works and temp dosent need to be as hi as whit flux.

 

But modern steels are different than old stuff..or new Bloom,Kera, Oroshigane..

In these we have lots of gases, flux...we need to get these out..not but more in..

Whit modern steel there is not that much these anymore...and we really dont whant them in there..that is weak link

 

About japanese flux´s...tetsuro and straw CC + clay works bit like borax...even its not borax..they will lower melting zone of oxides in betweel layers...

so its washing away most of the slag( flux).

 

Soaking billets long times at hi temps will make bond stronger sens there is movement between materials...you can see this iron and hicarbon steel..demigration is huge if its soaked long times...this is greating issues later if they are not taken care at some state.

 

Also when using modern steel´s billets oxide level is ingreasing but using ore blooms,keras,oroshiganes...its degreasing...during folds and weld´s.

 

So I think material and right welding method is importat issue...also the forge is one issue more....fuel...hammering style, tools...

 

Niko

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This is so friggin' awesome. I'm hanging up my 7" grinder. Woo hoo!

 

--Dave

This is indeed "friggin' awesome" Congratulations! Forging in a gas forge without flux, wow!

 

The whole kerosene thing to me is a none event. It's been talked about for several years, if not much longer. Using kerosene for flux is not some sort of magic. Kerosene leaves a film on stuff and likely when put into a fire does the same. Anything that protects the iron will prevent of farther oxidation, sand dirt, mud dobbers nests, etc.

 

However, the idea of controlling the oxygen content of a gas forge to the point of being able to successfully and consistently weld without any flux, that's a new path. Now I want to see a lap weld :-)

Edited by Gerald Boggs
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Very interesting thread.<br />Alan, thank you for sharing your readings on oxidizing vs. reducing re; decarb. Compelling and confusing!<br /><br />Re; fluxless welding in solid fuel forges vs. gas forges; I have done a lot of fluxless welding in a coke forge, and have never, ever succeeded unless the surface is at least "sweating". Are we talking about a "sweating" heat in a gas forge? I am curious to know, but I think it might turn out that fluxless welding in a gas forge and fluxless welding in a solid fuel forge are two rather different beasts.<br /><br />If I might also add, a pet peeve of mine, the British fluxless welding thing- I am skeptical of the idea that this is due to better materials rather than stuffy dogma. Very skeptical!<br />

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Gary, the closest to a simple alloy 10xx steel they tested was their version of W-1 (10135 1.05% C, 0.2%Mn, 0.2% Si), but I don't see why it wouldn't be the same for lower carbon versions. From the way I understood it, basically any time you have a vast amount of CO2 in a furnace it will scavenge carbon from the surface to produce more CO. A slightly reducing atmosphere is mostly CO, but a strongly reducing one will be a mix of CO and CO2. There's just too much I don't know about it to say definitively where the line is, but I'll see what (if anything) they say about the ratios when I get home.

Edited by Alan Longmire
screwed up the %C
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Very interesting thread.<br />Alan, thank you for sharing your readings on oxidizing vs. reducing re; decarb. Compelling and confusing!<br /><br />Re; fluxless welding in solid fuel forges vs. gas forges; I have done a lot of fluxless welding in a coke forge, and have never, ever succeeded unless the surface is at least "sweating". Are we talking about a "sweating" heat in a gas forge? I am curious to know, but I think it might turn out that fluxless welding in a gas forge and fluxless welding in a solid fuel forge are two rather different beasts.<br /><br />If I might also add, a pet peeve of mine, the British fluxless welding thing- I am skeptical of the idea that this is due to better materials rather than stuffy dogma. Very skeptical!<br />

good points and post Dan.

fluxless welding at a temp where you lose a lot of material due to melting/ burning ie the standard british forge weld with jumped up excess materia . lsure seems like a different kettle of fish to this.

I will try my own go at this tomorrow.....

forging soul in to steel

 

owenbush.co.uk

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No doubt there is a a bit of "stuffy dogma" Perhaps it's also a case of understanding the benefit of welding without flux. Remember, most forge welding is done within the realm of architectural work. If you forge without flux, that's it, you're done. However, when you use borax, you then have to soak the piece in acid and then wash it off in a water/baking soda mix. Because if you don't, in time you'll get the nasty white powder buildup everywhere you used borax. If you have large scrolls that you've welded with borax, how large of tank of acid will you need?

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Alan,

 

Thanks for the insight. I'm curious. You talked about alloy steels and decarb. Did you find anything as to the effects of a long soak on simple 10xx steels (other than grain growth)?

 

Gary

 

With that book now in hand, the figures are for a five-minute soak at 1450 degrees F for W-1, and the graph shows decarb starting at an atmosphere of about 5% CO, with one of 6% CO causing loss of 0.1%C in that five minutes. This means that W-1 just became 1090 in five minutes... :blink: This is surface decarb, but as we know carbon moves fast. So, a longer soak would create a thicker skin of higher decarb.

 

The shortcoming of that book is that it's just about Carpenter's tool steels from 1960, so a lot of info is outdated. If you have some old-stock Carpenter L-6, though, it tells you it will decarb severely at anything less than a 4% oxygen atmosphere...

 

What I am seeing, though, is telling me something else: What we generally think of as a "reducing" forge atmosphere actually looks like what they're calling a slightly oxidizing one. Now then, what does that mean? The ambient air is 21% oxygen. If you adjust a gas forge to look reducing by turning up the gas until you see orange flame rather than blue dragon breath, it's probably not truly reducing. Of course, the guys who wrote that book would cringe to see us using a totally uncontrolled atmosphere to HT in. Their minimum requirement is a muffle furnace. So, using a pipe in the forge with the blade in a pipe would be acceptible, as long as the wood block test mentioned earlier showed the right results.

 

All the above made me rethink going to an electric furnace for sword blades, since the authors noted that in an electric furnace you are always running in a 21% oxygen atmosphere, the highest concentration naturally available. This also causes decarb, but even worse is the amount of scale.

 

Just more stuff to think about. :rolleyes:

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funny I have never had much of an issue with Decarb, until recently. I am getting very bad decarb on the L6 kitchen knives I am making, it isn't a big deal so long as I account for it but I am getting 4-5 thousandths that is unhardenable. this is in a digital controlled electric kiln with the brownells anti scale (oddly I am getting almost no scale)

MP

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The lack of scale shows the Brownell's stuff is working like it should, but from what the guys in that book were saying, anything over 6% oxygen decarbs most things. Have you tried using stainless foil with a tiny bit of paper in the package to scavenge most of the oxygen? Might be worth a shot...

 

L6 was the biggest example of the effect of furnace atmosphere, but it must be noted that the three air-hardening alloys Carpenter was making in 1960 decarbed no matter what.

 

I really wish that book wasn't still under copyright so I could post the graphs and so on... <_<

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I'm curious about the de-carb effects of the reducing forge. Like you said earlier, it goes against much of what we think we know. What is going on differently in a reducing gas forge to cause de-carb than in a primitive charcoal smelter, also reducing, where you are carburizing iron into steel? Just little differences in the ratio of CO to CO2?

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I think whether or not this technique will prove appropriate will depend much on your set up and way of doing things. Personally I set my welds in a press, I think this method or kerosene is going to work out much better for me than flux (no I still haven't tried either). With flux I am getting inclusions more than I care to admit, and while refining my technique may help it certainly won't completely eliminate the problem. For those setting welds with hammers or using solid fuel forges flux may remain the better option (though I know one person who has made some very nice billets on a hammer w/ this technique).

I am a little concerned about the issue Alan brought up about decarb, especially with the long soak times being reported. That too will ultimately be a choice one needs to make, but it seems like if your not losing carbon then your losing iron.

Anyhow I am still very excited about this, and can't wait to get my forge rebuilt and some steel ordered.

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well tried it and seems to work incredibly well.

I welded up a standard 7 layer stack for me and twisted a 1 foot section 31 x 360 degrees.I forged a bit of it into a knife.

so far so good.

If anything I have a feeling that the weld is better than my normal flux welded version ,less layer separation at the edge (none in fact).......

I welded under a 50 kg power hammer and did nothing different apart from turning the gas up and not fluxing.

Thank you J D Smith for sharing this.

forging soul in to steel

 

owenbush.co.uk

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I'm curious about the de-carb effects of the reducing forge. Like you said earlier, it goes against much of what we think we know. What is going on differently in a reducing gas forge to cause de-carb than in a primitive charcoal smelter, also reducing, where you are carburizing iron into steel? Just little differences in the ratio of CO to CO2?

 

A forge and a smelter are totally different atmospheres, and I suspect there are too many variables involved to make a blanket statement (not that that ever keeps me from trying :lol: ), BUT: With a charcoal smelter or hearth furnace, there is so much more carbon available in the form of the charcoal itself it tends to be the charcoal that loses carbon rather than the steel.

 

In a gas forge there is no extra carbon available beyond what's in the fuel and what's in the steel, and if the atmosphere is scavenging carbon it's going to come from somewhere.

 

What I think is the most important point of this side-thread on decarb and reduction is that the experiments I have been quoting were done in SEALED controlled-atmosphere HT furnaces. When we are using a gas forge, especially a venturi forge, I don't think it's technically possible to get true reduction going on. I am sure that a venturi forge with open ends can't be made to run with less oxygen than a true neutral atmosphere. This will result in absolutely no scaling, and may be the perfect welding atmosphere as far as I know (which isn't all that far). A blown gas forge with nearly closed ports can run a few percent reduction, but I doubt we're getting past that 4% threshold that causes decarb.

 

The previously mentioned authors kept saying the single biggest influence on decarb in a furnace is the amount of water vapor getting into the air/gas mix. They didn't go into the specifics, and may not have understood them, but I do know that hydrogen is an even more powerful reductant than carbon (which is one theory as to why a water-powered Trompe blast worked so well in Catalan furnaces), so it may be that on really humid days we get more decarb. I know I find it harder to weld on humid days.

 

To sum up, I don't think y'all are getting into a true reducing atmosphere far enough to affect the steel using this method. I'm willing to bet if you try the wood block test it WILL burn with visible flame and/or smoke, which cannot happen in the absence of oxygen.

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