welding up a tri-lam (san mai)

ScottRoush

ScottRoush

Joined
Jan 10, 2010
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i'm welding up my first billet for a san mai blade. i'm using a 110v gasless wirefeed welder with flux core. i'm wondering about contamination from the welding points. i'm assuming you want as little of the the weld getting forged into the blade as possible? should the welds get ground away as much as possible before forge welding?

thanks!
 
What you want to do is just tack the corners and a spot on each side in the middle to keep the center from bowing outwards. Then do your forge welding and get it solidly welded and drawn down by about 1/3. This will make sure your weld is set well. After that, grind off your arc welds so that they don't contaminate your pattern.

-d
 
Deker is right !
OT - Lincoln Electric now makes a neat training device .It's virtual welding.You have a set-up and go through the motions but what you see through the helmet is virtual only ,arc , bead .It also saves data so you can compare today's and tomorrow's work. Of course the big saving is no material is used !
 
mete said:
Deker is right !
OT - Lincoln Electric now makes a neat training device .It's virtual welding.You have a set-up and go through the motions but what you see through the helmet is virtual only ,arc , bead .It also saves data so you can compare today's and tomorrow's work. Of course the big saving is no material is used !
Click to expand...

Wow...I bet THAT'S cheap....I want one! :)

-d
 
Be sure to run the hammer down the center of the billet first to reduce your chances of getting a bubble in the center.
 
Moss,

What are you welding?? If it is carbon steel in and out then Deker is right on the money. If you are trying the 416 outer with a carbon inner then you need to seal the billet. Run a bead around the outside. Then do your forge welding. Avoid striking the edges and do your flats. Once you have your distal taper done grind off your bead. You will be able to see the difference in the materials and it will be obvious once you get all your weldment off. Dry welding is great. This is the same process that I use on all my Damascus now. It really helps improve your forge welding. Good luck
 
thanks... it is unknown bandsaw (no carbide tips) steel on the outside...1084 on the inside. i kinda started this on a whim as an experiment.
 
good thing this was just an experiment because it failed. i guess the band saw blade is just too thin (just <1/8"). it bowed up heavily in between the middle weld as soon as it started to heat up. i'm assuming that once it bows up you're screwed as scales forms on your welding surfaces?? but... i decided to flux and try to forge anyway just for practice... (i've never done this before). at the top of the billet it was still fairly tight to the core so i thought i would try to see if it would weld. i added flux as soon as it started to show color... but i kinda got lost as to when to start trying some blows. the flux pretty much diappeared.. and the bandsaw layer was getting yellow and heating up much faster than the core.. so i gave her a couple of whacks... a couple on each side in seperate heats. one side seems to have started a weld.. the other side just broke and bowed off. after letting it cool i noticed that the flux was remaining as a tough transparent residue. i assume i never fully achieved forge welding temps then???

which brings up another question... when adding flux.... how much, how often and where exactly? just right on top of the outer layer?

anyway.. this is all just for fun as i'm awaiting an injury to my left hand to heal... but eventually i'd like to master this. my next attempt will be with a thicker piece of some kind of mild steel.
 
Dry welding is the answer... If you had welded up the edges completely sealing the billet this probably would not have happened. That is one nice thing about dry welding. Another is NO flux. Since the seams are sealed there will be no scale on the mating surfaces. I occasionally use a little to protect the outside of the bullet but it works without flux. Also with dry welding, you can weld at a lower heat. By your description it sounds like your atmosphere may have been too oxidizing. Make sure it is either neutral or reducing. Try again and let us know how it goes.
 
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what exactly is the definition of dry welding? are you talking about the whole process of completely welding the billet.. instead of just tacking it on the corners and middle.. AND not using flux?

as to my forging conditions... i use a single venturi burner (a zoeller-type side arm) with a choke.. and i had it shut halfway, blue flame and flames shooting out the front. i didn't actually see a lot of scale formation.. i just figured the surfaces were compromised in some way by bowing up and getting exposed. this brings up something else.. on my forge (a portable air tank on it's side) i tend to leave a small opening (2 square inches) on the back to allow it to 'breath'... when i'm forge welding, should i close that completely off?

also... if I AM using flux... should it leave that clear, hard residue or should it burn completely off??
 
Let me just refer you to the welding section of my website. It contains my complete writeup on the welding process. In general, you want thicker stock on the outside of a billet if you can manage it. It is possible to weld something like you've described up, but you can see what some of the challenges are already. One thing that jumps out at me from your description is that you had blue flame exiting the forge. The "dragon's breath" from the forge should really be orange. If it's blue, your atmosphere is likely off and your temps are possibly too cool.

Yes, Chuck was referring to arc welding the entirety of the seam of your billet and then not using flux at all. That's commonly referred to as dry welding.

Go take a read of my website (the section on preparation is also an important one) and see if it clears anything up for you. I'm working on getting more content up there (including pictures of the processes), but it's slow going as life has been interesting for me for the past while. If you have any questions though, feel free to email me or just keep posting in this thread. I'm pretty sure that between all of the folks here on BF we can get you successfully forge welding in no time :)

-d
 
great... thank you. but no... i probably wasn't clear. i have orange flames exiting the mouth... and blue flames just where it is entering the forge. i've done my best to tune this forge using descriptions and pictures of other folks flames! i really need somebody to come out and look at my set-up but i live so darned far away from other smiths!
 
Mossanimal said:
great... thank you. but no... i probably wasn't clear. i have orange flames exiting the mouth... and blue flames just where it is entering the forge. i've done my best to tune this forge using descriptions and pictures of other folks flames! i really need somebody to come out and look at my set-up but i live so darned far away from other smiths!
Click to expand...

Ahhh, ok. Well then what you're looking for is the billet looking "like a stick of butter in the hot sun". Or, to be more concise, a yellow heat with the flux bubbling slightly on the surface.

As to when to apply flux, you should start doing that when the steel starts to pick up any color. It will melt and flow on steel that's at a red heat or above and just kind of hang out and "ball up" on steel that's too cold. Either way, if you flux early in the process you'll be sealing out oxygen which is more than half the job of the flux in my shop.

For your next attempt, I'd try putting your thin stock in the center so that you have something with more structure on the outside. It will avoid the buckling that you were seeing with your first attempt and allow you to concentrate on the variables of temperature, flux, and setting welds without adding an unnecessary degree of difficulty.

-d
 
thanks again.... so... the fact that my failed billet still has the clear, hard coating of flux is probably due to the fact that i stopped working on it when i realized it failed? and just never carried on long enough to burn it away?

as to the flux bubbling on the surface... it seems like it all disappeared before it got to any welding heat... but perhaps it was just surviving as a clear liquid and not yet bubbling.

anyway... i have Aldo sending me some thicker stuff to play with.

one more question on this topic. i was thinking of cutting some my of old table saw blades into strips wide enough for an outer layer over the 1084. i'm assuming these blades are high in nickel and other alloys... so... how much of this migrates into the core and therefore affecting the heat treat? i was hoping the high alloy content would provide more contrast with the 1084...

if somebody can suggest a good resource for this, i can check that out rather take up more time....
 
I think I understand dry welding more now. When I read about it in another thread I thought it was referring to welding up the initial billet with no electrodes. That somehow the outer edges of the layers of metal were fused together using a welder, but no rod, wire or flux to get it sealed up. I was at a loss as to how to do that.

So to do dry welding/forging, there must be a heck of a lot of grinding or milling of the sealed edges with all the foreign weld material that was used to seal the billet up?
 
Mossanimal said:
thanks again.... so... the fact that my failed billet still has the clear, hard coating of flux is probably due to the fact that i stopped working on it when i realized it failed? and just never carried on long enough to burn it away?
Click to expand...

Yes, that glassy black coating is flux that you just let cool. Usually what gets rid of the flux coating is forging. It will fall off with scale as you work the steel.

as to the flux bubbling on the surface... it seems like it all disappeared before it got to any welding heat... but perhaps it was just surviving as a clear liquid and not yet bubbling.
Click to expand...

How much flux were you using? Did you sprinkle it like rare, magic pixie dust or really lay it on? I'm guessing more towards the latter due to your description of the current state of your billet, but it's a question that needs to be asked.

anyway... i have Aldo sending me some thicker stuff to play with.
Click to expand...

You won't be sorry for that one :thumbup:

one more question on this topic. i was thinking of cutting some my of old table saw blades into strips wide enough for an outer layer over the 1084. i'm assuming these blades are high in nickel and other alloys... so... how much of this migrates into the core and therefore affecting the heat treat? i was hoping the high alloy content would provide more contrast with the 1084...

if somebody can suggest a good resource for this, i can check that out rather take up more time....
Click to expand...

Who knows what is in a circular saw blade. There are likely alloying elements that will make your welding harder (Chromium comes immediately to mind). I'd stick to known, simple steels, especially if you're having some issues getting things to set right. You really want 1084 and 15n20 to learn with. It's the easiest combination to deal with. Move on to higher alloy stuff if your work mandates it later, but do so with an understanding about what those alloying elements will do at welding heats. For now, concentrate on the basics and your process. Process is the most important thing in making damascus.


-d
 
bam! thanks a lot. that really helps...

no i laid it on heavy. reaaaall heavy. i figured if a little was good.. why not a lot?! lol.... like i said.. just having fun. but it's gonna get serious next time.

i really appreciate your help... next i will check out your website...
 
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