Jump to content

NO FLUX WELDING


Gary Mulkey

Recommended Posts

Thanks Alan,

 

That eliminates a lot of my concerns about decarb. I didn't have a lot of worries about the no-flux aspect of this but converting the existing scale to steel was my biggest concern (and the longer soak required) and I think that you have answered that.

 

Thanks,

Gary

Gary

 

ABS,CKCA,ABKA,KGA

Link to comment
Share on other sites

no sweating and no wet, just hot but not really as hot as I would normally have it when welding in a gas forge with flux.

forging soul in to steel

 

owenbush.co.uk

Link to comment
Share on other sites

On the ABS forum folks had the forge running 2200-2400degf but when JD demoed it at my place I don't think my forge was running that hot more like 1900-2100 degf a good bright yellow heat not even close to white. As seen in both mixed light and later just under florescent light.

MP

Link to comment
Share on other sites

I tried this again and have come to the conclusion that my Vaughn's "weed whacker" burner is not the way forward for this technique.

Gerald Boggs, on 02 Dec 2013 - 19:03, said:

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?

Gerald, I just brush off the borax gunk, no acid bath or anything; I've never had a problem.
Link to comment
Share on other sites

Gerald, I just brush off the borax gunk, no acid bath or anything; I've never had a problem.

Meant to reply days ago, but the weather wasn't good for a photo. Anyway, just to make sure we're talking about the same thing, here's two photos. The first is two tree branches left over from a job I did about two years ago. They've been sitting on the "Someday I'll do something with these" shelf. As you can see, there's a heavy build-up of white crud. This is what happens when you use borax and do nothing to remove the residue. This is a worse case example, as all I've done is hand wire brush. The second photo is of a twisted fire basket I did about the same time. As still happens in America, a "blacksmith" told me you couldn't forge weld without flux. I showed him otherwise. Been hanging on the wall of same shop. No buildup beyond a little rust

 

.

Picture 579 Large Web view.jpg

Picture 581 Large Web view.jpg

Edited by Gerald Boggs
Link to comment
Share on other sites

Vey nice work, Gerald.

I am familiar with the white crud. It can be easily removed by thorough brushing while the work is hot.

I am not partisan in the question of flux vs. no flux. It is not really even a question for me. Do what is best for the work. By using flux I can weld at a much lower heat (solid fuel) than without. That means less wastage, very important for ornamental work.

But anyway, this topic is actually about fluxless welding in a gas forge, which has been confirmed, to my satisfaction at least, to be a different thing requiring different skills.

Link to comment
Share on other sites

One thing I have not seen mentioned is soak time after hammering or pressing the layers together. John Emmerling mentioned using 15 minute soak to give the layers time to diffusion-weld. The idea here is that diffusion welding happens in the forge, not at the press or hammer.

 

I've had luck doing a few no-flux welds this way. What are other people using for soak times *after* pressing or hammering the layers together?

 

Matthew - I'd also gathered elsewhere that JD Smith welds at lower temps than I'm used to. I wonder how long he soaks the billet doing "bareback"?

Posted Image
Michael Kemp

Old and Twitless
Link to comment
Share on other sites

I had a go at this today. I put together a billet of 10 layers of 15n20 and plain carbon steel. Billet size was about 30mm square. A very strange experience, as for the last 20 years I have always used borax. So I was breaking the habit of a lifetime and desperately trying not to use flux. I resisted the temptation and welded the 10 layers up with no problems at all. All done at a high yellow heat.

 

Then I drew the billet out, cut and folded it. I made sure my cut was on the 15N20 layer so the side that folded together for the weld was the plain carbon layer. No luck at all with this weld. It looked for all the world to have welded up but came apart all along the weld seam. So I unfolded it, added borax and carried onto 160 layers using flux.

 

When it had cooled down I cut a few slices of the bar, ground it to a 400 grit finish and etched. No bad areas or slag lines at all, so the first weld worked a treat.

 

Unless I am missing something, the only merits to not using flux is that the lining in our forges will last longer.

 

Mick.

Link to comment
Share on other sites

Vey nice work, Gerald.

I am familiar with the white crud. It can be easily removed by thorough brushing while the work is hot.

 

OK, you might be right and I'll have to give it a try. Just so I'm clear, one more question and I'll let this go:

 

You say if that after you've welded a few bits, say a couple of scrolls

or water leaves, all one needs to do is give it good wire brushing while

it's still hot?

Link to comment
Share on other sites

Gerald Boggs, on 10 Dec 2013 - 23:11, said:

OK, you might be right and I'll have to give it a try. Just so I'm clear, one more question and I'll let this go:

 

You say if that after you've welded a few bits, say a couple of scrolls

or water leaves, all one needs to do is give it good wire brushing while

it's still hot?

There might be some crud crumbs between branch welds, which can be mostly got rid of using an old hacksaw blade to get down in between.

By wire brushing when hot, I am referring to a hand held brush. Some people believe that if you dip the brush in water it works better.

Link to comment
Share on other sites

This is very interesting to me.

 

im curious about the practical requirements to achieve this though.

 

I am about to build a new forge and want to make one specifically with this clean dry welding in mind.

Are we looking at a gas and air mixture with control on both parts for best results?

 

I currently have a venturi burner forge which I borax weld mild steel and carbon a lot. But I tried a wd40 weld a few weeks ago with no success. I assume this is down to the lack of control I have over the flame/environment. The control I currently have over heat/ atmosphere is gas off, gas on a little, gas on more and gas on full.

 

The principal I assume is to have similar controls (valves) as you would over an oxy propane blowtorch, tuning the atmosphere and gauging by the flame.

 

So would the best way to introduce air and then control it would be a with a blown burner with a gas mixing chamber?

Onen Hag Ol.

Link to comment
Share on other sites

Unless I am missing something, the only merits to not using flux is that the lining in our forges will last longer.

 

Mick.

 

Mick,

 

I don't hot fold. I grind clean between welds, cut and stack. So, in addition to saving the forge lining, this has made prep time between welds MUCH quicker. Grinding away cold flux is my least favorite shop activity.

 

Cheers

 

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

Link to comment
Share on other sites

Dave,

 

You are right by assuming I hot fold and that may be the reason why the first weld of 10 clean layers, welded up with no problems.

 

Everyone that does this type of work, have their own ways of doing it. The reason I don't grind clean, cut and restack is mainly to keep a momentum going and heat in the forge, so saving time and gas. From the first weld to the final weld, the bar will not drop in temp from an orange colour at anytime.

One thing I do that is probably different from how most people weld up a billet, is that after hot cutting the billet I will flux the surface to be welded. Put the billet back into the forge and get some more heat in it. Then wire brush it clean, re flux and fold over ready for the next weld.

 

The only time I clean up the surfaces for welding is if I am doing some multi bar stuff, and more often than not the bars need to be cold for matching up the pattern.

 

Next time I am welding, I shall try the grind clean between welds and see if that makes a difference. It is also very difficult to break the habit of not using flux after nearly 20 years of doing so.

 

Which reminds me that the bottom of my forge is a horrible gooey mess, with a molten pool of "larva" that if it eats any further might just drop out the bottom, the next time it gets used.

 

 

Mick.

Link to comment
Share on other sites

I grind clean between welds, cut and stack.

 

Dave

 

I've found that the temp for welding and the temp for converting scale to steel is much the same and have quit surface grinding for a cut & stack. This REALLY SAVES TIME. Sometimes I will get a little black line on the edges where it didn't weld perfectly all the way to the edge but that has been small enough to come off with my typical rough grind of the blade. I suppose that if I were doing a complicated pattern that I had a lot of time invested in then I might play it safe & grind the pieces clean but for a typical random pattern I don't and so far haven't been sorry. :) Maybe now my work shirts won't have as many burn holes in the front of them from grinding.

 

 

Gary

Gary

 

ABS,CKCA,ABKA,KGA

Link to comment
Share on other sites

Josh

JD demoed this in my forge running a venturi and it worked fine. I think it maters more is the temp is high enough and the a enough soak for the chemistry to happen.

Kevin Cashen wrote up his experiments with dry welding along with micrographs of the welds, it is on his web site.

www.cashenblades.com/dryweld.html

Link to comment
Share on other sites

Gary --

 

Holy cow! No grinding between welds too?! I was just happy to only grind off scale and not cold flux.

 

I have to try this.

 

--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

Link to comment
Share on other sites

Dave,

 

I do think that there is some value in grinding the edges but at least so far I've found that surface grinding just to remove scale isn't mandatory like I used to think. This sure speeds up my time spent on a billet and increases the size of the finished billet as well.

 

Hope that it works for you as well.

 

Gary

Gary

 

ABS,CKCA,ABKA,KGA

Link to comment
Share on other sites

The principal I assume is to have similar controls (valves) as you would over an oxy propane blowtorch, tuning the atmosphere and gauging by the flame.

 

So would the best way to introduce air and then control it would be a with a blown burner with a gas mixing chamber?

Josh, unlike the Vaughn's weed whacker, most venturi burners have a slide valve (either a tab on a pivot or a sliding cuff type doo-dah. Hard to describe) for air intake as well as a valve for the gas. The nozzle of the burner is flush to the forge so there is no passive air intake in that area (as there is on your forge, or as there is a lot of on mine). I've not really read it but this site is normally recommended reading; http://www.abana.org/ronreil/design1.shtml
Link to comment
Share on other sites

To further explore this no grind method I made a billet today with absolutely no grinding just to see what would happen and must say it was mostly a failure.

 

Even though most of the welds took there were enough that had scale remaining that I wouldn't use this billet for a blade. I discovered the remaining scale in some of the welds after grinding with an angle grinder. To see if it would make any difference, I placed the billet back in the forge for an extended soak at welding temp with some but not total success in converting the scale to steel.

 

I guess that this shows that the process can be done but certainly isn't foolproof. The steel today probably wasn't a waste of time & money as I learned from it but it's going in the scrap pile either way. With enough time & temperature scale will convert (in a reducing atmosphere) but I'm not confident enough with doing it to let go of old proven methods yet.

 

Gary

Edited by Gary Mulkey

Gary

 

ABS,CKCA,ABKA,KGA

Link to comment
Share on other sites

The burner designs in burners for forges and Kilns by Michael Porter are great, I have built a bunch of these and found them to be as efficient and stable as the T-rex just a lot more time consuming to make and tune. for any of them I found that making a flare out of refractory and building it into the forge body works better and last longer the stainless flares I was wearing out 1-2 a month the first refractory flare I made is still working fine 2 years later...

Link to comment
Share on other sites

Just to add to the conversation, last night a forge welded a 30 layer 1080/15n20 billet (about 8 pounds) without the use of flux. I ran the venturi forge with several inches of "dragon breath", gave it a 15 minute soak, longer than I usually do and set the weld on the press. Forging the sides on the third heat did not pull any of the laminates apart. I only had an hour, so I drew the billet out, split it in half and will keep the forum posted on my success or failure.

 

Thanks

 

John

www.jmjonesknives.com

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...