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NO FLUX WELDING


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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 (

I try to hit 2450 F, but I have found that 2250 or above and I can weld 1095, 15N20, or W2 just fine. The most important thing is getting the entire billet up to temp. I usually start with pretty

My experience matches Joshua's pretty well.  My forge maxes out at a little over 2300F depending on the day.  I do a lot with 1084 or 1095 mixed with 15N20, and that all welds up fine with no flux as

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So I know how to get a reducing flame with propane but I'm using a diesel forge at this point, would a sooty flame be reducing? I've tried welding with no flux and it seems to work but when I grind it the welds don't look as "welded" as when I use flux. It's not like there's cold shuts but it's also not like it's one homogenous piece either. Anyone have any thoughts?

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  • 3 weeks later...

I have been doing this now for first welds and so far so very good.

I am adjusting my flame by putting a thermocouple into the forge and finding the hottest mix (which I presume is near neutral)and then upping the propane on a forced air forge , or shutting off a little air on a ventury. I do this until temp drops 50 or so C my assumption is now a reducing flame...

the type K thermo couples Tim Gunn kindly sent me read to 1350C my forge is often hotter than that, but whilst it is still in the 1200 to 1300 range I set the gas like this.

I found it very interesting that when I set my forge to what I would have previously considered as a neutral flame (light dragons breath)and then turned the gas up the temp rose considerably...to a point that had considerable dragons breath at optimum mix. quite possibly I have been running my forge a little lean.....or at least do not completely understand the relationship between gas mix and air mix and how it effects temp and the resulting dragons breath.

When using this method I am getting considerable flames out from the forge mouth when I tune to a 50C below optimal mix...

Edited by owen bush

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Well, I have been reading about this a while and decided to give it a try, especially since I am out of borax. Epic fail three times in a row.

 

Out of curiosity I tried the wood block test that was mentioned. When the block went in, the forge started belching all sorts of soft yellow flames. The block of wood itself just seemed to get black with no flames emanating from it. I increased air, and still had yellow flames out the front, but the block of wood seem to glow like an ember. I further increase air, and the flames sucked back to the block. My conclusion is that I have a slightly reducing atmosphere inside the forge. When I put in the block, it gave out extra hydrocarbons to burn, but since there was no available O2, they did not burn until they exited the forge.

 

Of course it was rain/snow/freezing rain today, which always makes welding more dicey.

 

I will get some borax and try my normal procedure tomorrow just to make sure I do not have anything else going on.

 

It would be nice to be able to ditch the borax.

 

Thx's, Fred.

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the fluxless method works much better with a press or power hammer to set the welds. JD did set one billet in my shop using a postvice to squeeze the billet and set the weld . that worked mostly but didn't get as solid a weld as the press or hammer and required a second guy to really crank down on the vice.

MP

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I had success and failure in my attempt to go fluxless. The first weld went fine (8lb billet) and the draw out went fine but during the restack, the top peice kind of bowed out during heating and I could see it was only in partial contact with the rest of the billet in the forge. It popped right off while setting the second weld in the press. The rest of the billet has been fine and clean. Maybe scale does form if there is ample space but not if everything is pretty tight together?? Maybe I will try to weld two separate peices that are not in contact in the forge and see what happens then?

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JD did mention that a close fit was needed and that if it separated the weld was less likely to take.

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yes, the fit is supposed to be close. If nothing else because there is more opportunity for a layer of scale to form in the trip from forge to press while out in the open air. This has been the thing that had always prevented me from fluxless welding in the past.

 

Notice how quickly a thick layer of scale forms in open air when you take a billet at welding heat out of your forge. I think the spaces have to be small enough so the heat can push most of the oxygen away from just plain pressure change due to temp, but this won't keep air from flowing into a big gap, and the bigger the gap the more oxygen available for each square inch or square millimeter of surface area to contact (as the distance between the pieces becomes wider there is more O2 available to react and form scale).

 

Just my ideas. I haven't had any failures yet with fluxless or kerosene/wd40, but I have avoided any big gaps.

 

kc

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“Years ago I recognized my kinship with all living things, and I made up my mind that I was not one bit better than the meanest on the earth. I said then and I say now, that while there is a lower class, I am in it; while there is a criminal element, I am of it; while there is a soul in prison, I am not free.” E. V. Debs

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  • 5 months later...

A short vid of setting a drawing a weld at NESM during my pattern welded seax class

 

Edited by Matthew Parkinson
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  • 2 weeks later...

ok now dave pushed me here after i asked about welding my first billit of damascus can a beginer do it this way or should i utlize borax for my first few welds

http://bearclawknives.com/ my mentor and his friends once told me there os no problem that cant be solved with a fine cigar and a pot of coffee

you know some people just need a sympathetic pat.....on the head........with sledge hammer

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I'd use Borax for the first time. Reduce the variables that might contribute to failure.

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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

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A beginner that has good fire skills with a well tuned propane forge, press or power hammer or mad hammer skills and patience/persistance, might be able to pull it off.

 

But practically speaking, I wouldn't advise it for your first (several) attempts at forge welding a billet.

James

Edited by James Spurgeon

Courage is resistance to fear, mastery of fear - not absence of fear. Except a creature be part coward it is not a compliment to say it is brave. ~Mark Twain

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ok then just trying to get all my ducks in a row before i attemot something new

http://bearclawknives.com/ my mentor and his friends once told me there os no problem that cant be solved with a fine cigar and a pot of coffee

you know some people just need a sympathetic pat.....on the head........with sledge hammer

Seven Points Forge by the Bay

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A short vid of setting a drawing a weld at NESM during my pattern welded seax class

 

Matt:

 

Holy crap. I don't know how I missed this video!

 

Can't get any more definitive or ballsy than that, dude. I watched as you rotated the billet 90 degrees after the briefest of weld sets and said to myself "Too soon, man! You're gonna get a weld failure." . . .then watched as you hammered the shit out of it with no shears. Wow. This is very convincing evidence that no flux welds are very strong indeed.

 

Thanks for this.

 

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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Dave I will admit to a bit of a pucker when I did that ... I was showing off and that has a way of biting one in the back side....

that said I did an experiment last week I will give a more detailed report when I have finished but, the basic idea is three billets all welded and draw in one heat 1st totally atmospheric 2nd with oil 3rd with flux. I welded all three in the same forge one after the other at the same temps, the soak time was the same for the first two and just a bit lower for the third (but two soaks as per my normal flux welding ) I will be cutting and inspecting the billets welds and etching to look for decarb, I also hope to cycle a few samples to see how long homogenization takes and get a sample of each tested for total carbon loss. ....

but the one thing I noticed was that unlike what I had thought would happen, the flux weld was just as strong as the other two showing no sign of delaminating even when drawn on edge...

MP

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  • 5 months later...

Ok, so I just finished reading this whole thread, and I'm curious about something.

 

Some people suggests that kerosene and paraffin make for good fluxes (for reasons they only seem to guess at). Ok, so what about that horribly thick lubricant used on cable? Is there a reason that wouldn't work like kerosene or paraffin?

 

Suppose you bought a brand new piece of cable. No rust. No dirt. Tons of that super thick lubricant. Could you forge weld that into a solid bar without borax? That would be a VERY interesting discovery, because I make the biggest mess with borax when forge welding cable. If I could somehow forge weld cable without borax that would be HUGE.

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Dan,

 

I'm probably the wrong guy to ask as I don't do cable but something that I believe would probably help with a no-flux weld with it would be to have a clamp/vise on the back of your forge so that you could un-twist & re-twist the cable while in a reducing atmosphere. This should make it easier to burn off the lubricant so that it doesn't contaminate the weld.

 

Gene Osborn used to do a lot of cable and used such a clamp with a high success on both old & new cable. ;) Just a thought.

 

Gary

Gary

 

ABS,CKCA,ABKA,KGA

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Dan -

 

While you may get some weld by creating a highly reducing atmosphere, I'm skeptical on the grease-as-flux hypothesis. Back when I made cable Damascus I would remove the heavy grease from the cable by burning it off. The result was a sooty, black coating that needed to be cleaned off with wire brushes and acetone before welding. I'm almost certain such a coating would foul the weld.

 

I'm the first to admit my intuition is often wrong when it comes to forge welding (see above . . . I would have never believed no-flux welding unless someone else had done it first), but for what it's worth, my bet's on a lot of inclusions and cold shuts if you try this method.

 

I hope I'm wrong, and I look forward to reports on your efforts.

 

Luck!

 

Dave

-----------------------------------------------

"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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  • 4 years later...

Well I gave no flux welding a try and it worked like a charm I did it in a charcoal fire though. Here is a quick and dirty etch. I'm going to get some burrs and a few stones and finish it up another day.

Resized_20190403_142527.jpeg

Resized_20190403_142514.jpeg

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