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Gary Mulkey

NO FLUX WELDING

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I'm a bit "old school" in that I was taught forty years ago to weld with borax but there has been so much talk on the forums recently about NO FLUX welding that it got me interested in experimenting. Four or five years ago Ron Newton showed me how to weld with kerosene rather than borax but I have never tried to do it without anything until today. I started with a typical 20 layer billet of 1084 & 15N20 and tack welded it with my MIG. I then placed it in the forge with no flux (or kerosene) what so ever. I left the forge adjusted with my typical six inch flame coming from the opening. After a short soak at welding temp I did my usual light squeeze in the press and back into the forge for another soak. The second time I did my usual heavy squeeze in the press.

 

To really test the welds I then did a "W" squeeze and drew it out. After cutting it into six pieces, I spot welded the pieces without any grinding (I wanted to see if leaving the scale one would make any difference.). I then placed the billet in the forge for a ten minute soak at welding temp and welded normally. The idea being that the oxygen free atmosphere in the forge would turn the scale back to steel and be eliminated. Here's the result:

 

nofluxbillet_zps3d05334b.jpg

 

Though it's a long way from a finished blade, so far I can't see any flaws. I guess the process works.

 

 

Let me know if you have done anything similar and what you think.

 

Gary

Edited by Gary Mulkey

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Hi Gary,

I fold and weld without flux. I find it needs a clean fuel though, charcoal or cleaner.

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You are far braver than I...

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we all saw a demo by JD Smith at Matt's hammerin. WD40 and then what JD characteristically called, "Bareback" welding (love JD).

 

Worked great. JD said he has experimented a lot, and that scale seems to block the process for him.

 

I am going to try this weekend with wd40 for safety. Insurance..

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Looking very nice!

Can you show us a pic of the 6 inch flame you are talking about? I think I am pictureing that right, but Id like to see a pic before I try it. ;-)

James

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Holy crap! That's awesome.

 

No flux AND no grinding between welds?!

 

Gotta try this myself. If I can make it work it would be a major time/hassle saver.

 

Thanks for sharing!

 

--Dave

 

PS -- Kevin: Can you briefly describe JD's WD40 method? Thx!

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Dave,

 

It has been popping up over on the ABS Forum for a few years now. I really wanted to see the demo at the ABS hammer-in in Topeka, KS a few years ago but, sadly, could not make it. Here is a link to the most recent thread about it on the ABS Forum: Dry Forge Welding Damascus (without flux or kerosene) If I remember correctly, the kerosene (or other carbonaceous substances such as WD40) reacts chemically in the forge atmosphere with the scale and you get the same reduction reaction that is used in a bloomery smelt. In other words the scale reacts chemically with the carbon, stripping the oxygen, and leaving behind metal.

 

~Bruce~

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Hi,

 

I always do the last two of my folds without cleaning and grinding, just a truckload of borax. This seems to go in quite nicely but there are always some little flaws. There are always a few little flaws in my billets even if I properly clean the faces up. I have been investigating the coal I am using as probably the root cause of this.

 

Is the above 'Bareback welding' only possible in propane forges?

 

Cheers,

JH

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I only use charcoal, I was taught to remove scale, by flooding the anvil with water then hammering the hot billet onto it, after the hinge is cut, the resulting steam blasts the scale off, you need to close the fold tight, before heating to weld.

I did try using coke forge for this, but I got a lot of slag incursion, and have not tried it again .

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I started my career in a blacksmith shop owned and run by an Englishman*, we never used flux. Yet I now use flux with most of my welds. I only weld without flux to maintain my skill, as a first step in teaching folks to weld and to show off.

The questions to ask are "What does flux do?" And "If it's possible to weld without flux, why use it?"

*Stokes of England in Keswick Virginia http://www.stokesofenglandusa.com/

 

I just read the ABS thread. I got to say, I found great amusement if how astounded folks sounded and the creation of a new name "Dry Welding" for something that's been done for thousands of years.

Edited by Gerald Boggs

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It's just my personal experience, but Brits tend to do things the hard way as a sort of national religion. Remember, though, for a loooong time the vast majority of forge-welding was done with wrought iron, which you can heat the living bejaysus out of without burning and tends to come with it's own built-in silica flux.

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It's just my personal experience, but Brits tend to do things the hard way as a sort of national religion.

 

Yep, that sounds like us! I borrowed a mate's power hammer the other weekend and he was shocked I brought borax :)

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While that does have a bit of truth in it, from my view, it's not quite correct. There's several factors that come into play.

First: In Britain, most of the shops I worked/visited use blacksmith coke. Blacksmith coke is/was a twice baked coke of very clean quality sized around 3/4 to 1 inch. Means you don't have the dirty fire problems that coal using Americans have with the (Not the best quality) coal.

Second: The standards of iron are higher in Britain. You won't get a load of A36 with high carbon inclusions or cracks down twenty feet of bar, as one does in the US. So Brits are starting with better materiel. It's a lot easy to reliability forge weld 1018 then A36.

Third: They never lost their blacksmith tradition, so useless you choose to go it alone, you can learn from trained, apprenticed smiths. Having someone that started as a apprentice when they were 15 and has been blacksmithing for forty years is a lot different from buying a book and trying to learn from it.

So all in all, if you can do the job without flux, why bother?

Edited by Gerald Boggs

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Gerald is right, it's a cultural and materials thing.

 

Flux is just insurance, it's not glue. As long as you meet the requirements of a forge weld (clean steel, neutral atmosphere, enough heat to encourage the weld, and enough pressure to make it stick) you'll get a weld.

 

If, however, you're having trouble with any one of those four requirements, flux lets you get away with a little slop.

 

My coal is dirty enough I like to use flux. And sometimes I get in a hurry and don't remove as much scale as is physically possible, so I use flux.

 

Then again, sometimes I use too much flux and the weld doesn't take because the molten flux blowout takes the layer of steel with it... :rolleyes:

 

It's all balance. B)

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Under thinking or over thinking. I did some surfing and spend this morning reading various articles/threads on welding with kerosene. Appears the idea, at least among bladesmiths, has been on the forums for several years. While reading the discussions, what I see the most, is a incomplete understanding of welding. One can be very skilled at a task (forge welding) and still not understand what's happening. Not understanding the process isn't a handicap in doing, but it is a handicap in understanding what's happening if a new element/variable is added.

Several questions that are absent in the conversations:
What is flux?
What is it doing?
Is it necessary?

Think of using a Oxygen/Acetylene rig. You can weld, yet there's no flux.* However, if you try to do the same with a Oxygen/Propane rig, you can't weld. Why one and not the other? *but if I braze, I must use flux.

Mind you, I don't have the answers, just the questions :-) OK, maybe I THINK I know some of the answers.

Edited by Gerald Boggs

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Hi, I came on the forum today to share some rather exciting developments with forge welding, but I see that Gary beat me to it. Anyway I'll just post the link to the ABS forum where a number of MS smiths have shared the methodology and science behind this. http://www.americanbladesmith.com/ipboard/index.php?/topic/1361-dry-forge-welding-damascus-without-flux-or-kerosene-topic-for-december-2013/page__view__getlastpost?s=474681b2ca8a57c0c1739148c4eb58b2

Very exciting stuff, it sounds like not only do we not need forge eating borax, but that this method works better that borax since there is not possibility for inclusions. JD Smith said he is getting 100% success rates and my friend John Emmerling has even welded difficult alloys including 5160.

I have not had opportunity to try it, since my forge needs relining (damn borax) but it sounds like as long as you have a reducing atmosphere you are good to go. Beyond that, temps are a bit higher than with borax (I think it said 22-2300f), and the first weld should be set gently. Give it a second welding pass and then you are good to go.

It is not clear how this method would work with coal or charcoal, but as long as the atmosphere is right it should be possible. I would be curious to here more on that.

I will post more in the coming weeks as I get my forge rebuilt and am excited to see what results others get.

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I will run a test with my 'normal house coal' forge next weekend and post what happens (expecting dismal failure haha!)

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I tried it and it worked like a charm! No WD-40/Kerosene. I just made sure it was a reducing environment.

 

6 layers of 15n20/1095, welded no flux.

 

no flux.JPG

 

I have since chopped it into three chunks and re-welded, also with no flux. I did lightly hit the billet with the belt grinder, before the second weld to knock the heaviest scale off of it.

 

This is a revelation! I HATE using the big wheel grinder between welds to clean up the scale/flux.

 

Thanks so much for starting this thread! You've savied me hundreds of future hours of mind-numbing grinding.

 

Grinning broadly,

 

Dave

 

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So, I understand the part about the forge being reducing. But what when you take the metal out of the forge? What prevents scale from forming instantly, obstructing the weld?

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So, I understand the part about the forge being reducing. But what when you take the metal out of the forge? What prevents scale from forming instantly, obstructing the weld?

 

I don't know! :D I just pulled it out and squeezed it in the press. Maybe there isn't time for it to form enough scale to foul the weld?

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I haven't had much time to play with this after JD demoed it in my shop, but I have been thinking it over a lot, originally I had thought this might not work with every type of weld, JD is well on the way to proving me wrong on that front, he has now pulled off an axe eye weld in mild and then welded in a high carbon bit with NOTHING no flux no oil nothing!!!!

The only question I see as still unanswered is if this will work better with solid fuel forge as it dose with gas, I know it will be possible in a coal or charcoal forge but I think it will be much more inconsistent and much more reliant on the skill of tending the fire correctly, it might also result in trapped pieces of coal or clinker in the weld, this I think will be more a factor of the grade coal used than any thing else.

 

What I find so amazing about this method is how much it speeds up the process, I was doing box welds for the majority of my Billets. It would take me 1-2 hours to prep my billets per restack, more if I was working with unpickeled stock and needed to grind off the scale. The prep for this method is less than a half hour that is a minimum of 1 1/2 hour time saveings per restack. This is the same reason I was moving to the kero/oil weld, this Bareback method is taking it just that much beyond.

MP

Edited by Matthew Parkinson

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I tried it and it worked like a charm! No WD-40/Kerosene. I just made sure it was a reducing environment.

 

6 layers of 15n20/1095, welded no flux.

 

attachicon.gifno flux.JPG

 

I have since chopped it into three chunks and re-welded, also with no flux. I did lightly hit the billet with the belt grinder, before the second weld to knock the heaviest scale off of it.

 

This is a revelation! I HATE using the big wheel grinder between welds to clean up the scale/flux.

 

Thanks so much for starting this thread! You've savied me hundreds of future hours of mind-numbing grinding.

 

Grinning broadly,

 

Dave

 

Not a problem. That's what this forum is all about. :) Maybe now my work shirts won't have so many burn holes in the front of them.

 

Gary

Edited by Gary Mulkey

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One thing to think about: I had a nasty cold last week, and spent the downtime reading old metallurgy books, especially the HT section of "Tool Steel Simplified" by Palmer and Luersson, 3rd edition (1960). There is a section in there about the effect of furnace atmospheres on tool steels that was very enlightening and totally counterintuitive, to me anyway. They recommended heating all their alloys in a slightly oxidizing (4 to 6% oxygen) atmosphere to avoid decarb. My first thought was "but that's against everything I've ever heard!"

 

However, they actually had run the tests on centerless-ground decarb-free 3/4" round bars of all their alloys at every atmosphere from strongly reducing to strongly oxidizing, then thin-sectioned the results, polished and etched, and ran 'em under an electron microscope to see what they looked like. In every case but one (L6, I think) a reducing atmosphere STRONGLY decarburized the samples. We're talking up to 1/8" deep on W1, taking it from 1.3% C on the surface to 0.6%C on the surface in a 2% reducing atmosphere.

 

Conversely, at a 5% oxygen atmosphere the alloys all actually GAINED surface carbon from the CO in the furnace! Up to 5% gained on W1 on the surface. The tests indicated that decarb under reducing atmosphere was mostly due to excess water vapor from the unburned fuel picking up carbon, exactly the way we try to decarb bloom iron in a hearth.

 

You don't even need a gas spectrograph to test the atmosphere, they showed how to do it with wood blocks. In a true reducing atmosphere the block will not burn or even smoke, they just blacken. At 3% O2 they will smoke and glow on the corners, and at 6% they will burn with a lazy flame, leaving a lump of charcoal that glows uniformly. That told me that what I thought was a reducing atmosphere in my pipe-in-the-forge HT setup is actually around 3% oxidizing, or perfect for what I was trying to do.

 

I know, we're talking about welding here, not HT, but decarb is decarb and I do not want any if I can help it.

 

As a total aside, they also exposed a few other things that are "common knowledge" to be not true, such as the center of a bar taking longer to heat than the outside. For instance, the center of a 6" round was shown to be within 100 degrees MAX difference from the surface throughout heating, except while the steel was undergoing the transformation at critical when the center is actually a little HOTTER than the outside... :huh:

 

It sounds odd, but as a friend of mine once said, "We have charts and graphs to back us up, so f^&% off." :lol:

 

The chapters on quenching are well worth reading as well.

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So, I understand the part about the forge being reducing. But what when you take the metal out of the forge? What prevents scale from forming instantly, obstructing the weld?

The temperature that scale will melt and the temperature for welding are close together. If you take the iron out at a temperature above the scale melting point, you have a small window before solids form. If you watch iron heat up, you can see the oxide start to melt. I was taught to look for melting ice. At that point, you can weld without flux. An easy way of seeing the process, is to take two pieces of 3/8 round and put them into the fire. I use a coal fire most of the time, but it should work in a gas fire. As the iron heats up, start tapping the bits together. Just before you can see the scale melting, you'll feel the bars start to stick. If you were using flux, at this point you could weld, as the flux appears to lower the melting temperature of scale. This is sometimes called a "sticking weld" (I think that's right?) As the iron continues to heat up, you'll see the scale melt. Wait a few moments longer for the iron to get above the melting temperature, hold the two bars against each other, remove to anvil, hammer and you should have a weld. This is the first thing I have folks do when I'm teaching them to weld.

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The temperature that scale will melt and the temperature for welding are close together. If you take the iron out at a temperature above the scale melting point, you have a small window before solids form. If you watch iron heat up, you can see the oxide start to melt. I was taught to look for melting ice. At that point, you can weld without flux. An easy way of seeing the process, is to take two pieces of 3/8 round and put them into the fire. I use a coal fire most of the time, but it should work in a gas fire. As the iron heats up, start tapping the bits together. Just before you can see the scale melting, you'll feel the bars start to stick. If you were using flux, at this point you could weld, as the flux appears to lower the melting temperature of scale. This is sometimes called a "sticking weld" (I think that's right?) As the iron continues to heat up, you'll see the scale melt. Wait a few moments longer for the iron to get above the melting temperature, hold the two bars against each other, remove to anvil, hammer and you should have a weld. This is the first thing I have folks do when I'm teaching them to weld.

 

Excellent, thanks! That's great information to have. I will have to do some experimenting with that to recognize that. I just looked it up, the melting point of scale is 1369C (http://www.reade.com/products/35-oxides-metallic-powders/270-feo-mill-scale-ferrous-oxide-iron-oxide-rust-ec-dust-scrap-steel-residue-wuestite-cas-1345-25-1). 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.

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