Fluxless damascus welding. A short synopsis

[gearhartironwerks]

Greetings from the great Northwest,

 

This is a short synopsis of some of my experience in welding damascus billets without the use of flux. Please feel free to add to, disagree with, or at least chime in and share your experience.

Thanks for looking.

John Emmerling

 

Gearhart Ironwerks

Gearhart, Oregon

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Recently, there has been some discussion regarding flux-less Damascus welding. I
thought I’d share some of my experience in doing so for the past several years.
I first heard about the process from Tom Ferry, ABSMS, at an NWBA conference about
5-6 years ago. He said he hadn’t been using flux for the past 6 months or so at that time.
I didn’t believe him, but thought if he could do it, so could I. I came home and tried to
weld as usual, but had no luck after several tries. Frustrated, I went back to flux.
Several years later I watched ABSMS, Bob Kramer weld without flux at a conference in
a forge that no one thought could get hot enough to weld in, much less without flux. Bob
had no thermocouple or pid reader to control the forge. It was amazing and I was hooked.
I then began to research the process on-line and absorb everything I could find to have
consistent results welding. What I have found is that forge temperature control is
paramount to eliminating guesswork and will pretty much guarantee success in making
clean welds.
There is some expense involved, but not much. A pid reader and K type thermocouple
capable of handling about 2375 deg F are the main components. Both can be had for
under $80, less if you shop them around (ebay). MS John White used a hand held battery
operated reader and a thermocouple at a demo at the Batson symposium last year. Mine is
120v. It would be best to stay away from the point and shoot infrared guns as they are not
accurate when used in a forge.
The type of forge, whether blown or venturi, doesn’t matter. What is important is that it
has enough insulation and a good burner to get it up to welding temperature. I use a
blown forge with a ribbon burner and a needle valve for gas control, which works well
for me. I guesstimated a welding temp at 2325. John White welded at 2315. I don’t know
what the lower end welding temp is as I haven’t taken the time to experiment. Obviously,
lower would be better for the steel as grain growth is a product of temperature more so
than time.
Some smiths prefer to grind the mill scale and start with clean steel in the initial stack. I
have done it both clean and without grinding and haven’t noticed a difference in the weld.
Small amounts of rust don’t seem to make a difference either. Bob Kramer soaked his
clean ground billet in kerosene (light viscosity) prior to putting it in the forge. The theory
is that after the flash burns off, enough carbon is left between the layers to prevent
oxidation thus making the weld easier.
I use a power hammer rather than the hydraulic press as I seem to have a better feel for
the steel. Also, the hammer creates heat thru friction as opposed to the press dies sucking
out the heat from the billet. It’s just a matter of what one gets used to and what’s involved
in the design.
To start, I run the forge up to 2325 (with a rich atmosphere that has flames coming out
the front) and let it stabilize at that temp, then put the billet in. You will notice a temp
drop of over 100+ degrees immediately when the billet is inserted
When the billet gets to temp after rotating every several minutes, I like to soak it for a
few more minutes at temp, then go straight to the hammer to tap it together lightly on
both sides. Then back into the forge to soak a few more minutes, and out to hammer a
little harder. On the third pass, I hammer as normal to draw out the billet. My method is
to ‘massage’ the pieces together at first rather than to use hard blows. I’ve read that some
smiths simply hammer it out on the first pass at temp. Not liking to waste steel, I just take
it easy at first. After watching Kramer, and not always using clean steel, I give it a little
more forge time. That extra soak time may not be necessary, but it makes me feel good,
and there aren’t many failures because of it.
After the billet is drawn out, it’s important to clean off the forge scale prior to restacking
and welding. The steel doesn’t need to be perfectly clean, but pretty much so. I cut my
pieces to length and use a magnet to hold them against the platen of the belt grinder. A
surface grinder is a great tool for this as well. The idea is to have little or no air space
between the pieces for oxidation to take place. Another important factor is to never
remove the billet from the forge once you start the welding process as oxidation will ruin
the billet. In other words, don’t answer the phone.
This is a somewhat abbreviated version of my methodology, but it’s fairly simple to
achieve success in welding billets from flat stock without inclusions.
John Emmerling
Gearhart Ironwerks
Gearhart,Or.
www.gearhartironwerks.com

fluxless welding 1.pdf

[mitch4ging]

John, thank you very much for posting your synopsis, and the pdf!
Regards!
Dennis

[windancer]

John, one more thank you for puting this together. I have been kind of monitoring this topic for the past couple years. Nice to have this all in one place :)

I recently went on a Damascus 'binge' and did nothing but make Damascus for about a month. Figured if I was gonna make a mess of my forge lining I would get my money's worth. Ate the entire guts out of my forge and it still needs relining, along with another piece of kiln floor [the flux ate that too with so many welds being done one after another].

Does the flux-free Damascus welding eat up the forge, maybe from the long hours of high temps, John?

Dave

[Justin Carnecchia]

  Excellent write up John, thanks for taking the time to share your methods.

 

  I don't have a thermocouple, which I believe would help, but I have had excellent luck with what I'd call "mostly fluxless" welding.  I follow the same method John described for the first pass on my press.  For the second I add a bit of flux to the edges just to keep everything tight.  Since switching to this technique I haven't had any issues with inclusions, and though I've got a while before my damascus is nearly as nice as John's, this is definately a step in the right direction.

 

  Dave,  I was having similar experiences with my forge and welding.  Seemed like every time I went on a "damascus binge" it would destroy my forge and I'd have to rebuild it.  Since switching to my variation of the fluxless welding I've had no problems and my forge still looks like new after 8 months.  I suspect that in the long run the high temps will start to break down the lining eventually but you should be able to minimize that by using the high temp kaowool, and keeping a fresh coat of itc-100 on it.

[pike3e]

I have found that keeping the pieces of the billet in contact is the most critical part. The first weld is a breeze because the barstock is already flat. For me, restacks require that I get the pieces flat again or I run a risk of ruining the billet. A surface grinder with a belt conversion makes fairly short work of it, but the few times I skipped doing that and could see gaps between the re stacked steel, I had failures. 

[WayneCoeArtistBlacksmith]

This past weekend I was demonstrating my new Ribbon Burner forge (burner supplied by my good friend John Emmerling) and demonstrating the no flux weld.  Just about 1800 degrees the propane ran out and we had to switch bottles and then relight.  The billet stayed in the forge during the bottle change but, obviously, there was a period of time when there was not a reducing flame surrounding the billet.  With the forge relit the temperature came back up and I set the weld, figuring that it would be a failure.  As it was hammered I watched closely and it looked like it had welded.  I also turned it up on edge and it still looked good.  After it cooled down and looking at the edges the boundaries of each piece welded could be clearly seen.  I then went to the grinder and could see the lines as black (scale?) lines.  I kept grinding and down about 1/64" the black lines were gone and it was one solid billet.  After it was etched the layers appeared but nothing was noticeable at the suspect weld lines.  The billet was put in Iron In The Hat but I did not pick up who won it.  If the winner reads this please let me know and when you forge it out I would like to know how it worked out.

 

Now, after thinking about it I probably should have fluxed the edges lightly and maybe would have 1/32" more steal. Of course, fluxing would have defeated the whole purpose of the demonstration.

 

Thanks to John E for starting us on the Ribbon Burners and his input on Fluxless Welding.

[Justin Carnecchia]

Weird, not sure why my last post didn't work.

Anyway,  what I was trying to say is that,  I've had similar results with subsequent welds requiring a good cleaning and being fairly flat.  One thing that I've found really helps is to give the billet a gentle squeeze in the press as soon as it's at a good red heat.  This brings everything in close contact before there is any chance of oxides forming in the gaps. Then I put it back in and bring it up to welding heat and set the weld.

[Michael Kemp]

John  E. - Good write-up... with you, JD Smith, and Bob Kramer recommending it, I've tried the no-flux method with a couple of billets. Here's a photo of my latest one - approx 1/2"x1-1/8"xmaybe12":

 

 

seems solid - I'm working on making a chef's knife out of a chunk of it.

 

Michael Kemp