Help bad bad weld on my first mokume

[jsurgeson]

Hi

My first attempt at mokume using copper/brass, welded ok except there is a bad weld when I folded.

In order to fix this can I just reheat to weld temp and give it a smack to re-weld? Or do I have to live with it.

Sorry for the basic questions but I am only 1 month into blacksmithing.

Any help/pointers on how to fix and prevent in future would be appreciated.

[rock-n-time]

I can't say (In order to fix this can I just reheat to weld temp and give it a smack to re-weld?)what I would do is make sure you flux real good.I have not done this in a open heat, it's all ways closed oven. When I do this it is under perisher. Clamp, two stainless steel plates, A x B X C ? two to four bolts SS. then heat soak. Copper and like metals are way diffrent than steel. and when combind the melt temp changes.

[jsurgeson]

To be honest. after reading all I could on making mokume I tried the "clamp between two plates" but the weld failed.

I think this is mostly due to my inexperience, but I could not judge the temp as I could not see the billet. On second try I just wired together, heated and welded section by section as you would cable. I then folded down the middle, this is the bad weld.

This is more than likely not the correct way to make copper/brass mokume, but it is the only way I have managed to get it sort of correct.

[Frosty]

Diffusion welding for Mokume Gane is different in practice than "forge" welding though both are diffusion welding.

How did you clean the layers? Did you sand them bright, then degrease thoroughly and NOT touch them with your hands again?

Did you retighten the clamp as it got hotter?

Did you heat it to "sweating" temp and hold it there for a good long soak?

You have to be even more thorough after folding, all ALL scale must be removed and the faces need to match as closely as possible. Soak time will be at least as long as the first weld.

No flux necessary if you do it right.

The top 3 rules of welding apply even more strongly to diffusion welding Mokume Gane style.

#1. Clean.

#2. Clean.

#3. CLEAN.

Frosty

[jsurgeson]

Well thats my problem, as you can see in the image all the layers are perfectly welded except the center one.

The billet consisted of 4 perfectly flat brass & copper sheet, I did clean it very very well, steel wool, #2000 paper, IPA. Then bound without touching surface again.

After first successful weld, I then made the mistake of flattening it quite a bit, and then trying to fold the flattened billet in half, this all at weld temp, however the surfaces were now not so flat and dirty, and even though I fluxed it still did not weld.

What I should have done is after first weld, cooled, then cut billet in half, mechanically, then re-cleaned weld surfaces, and re-welded as before.

I did do this weld by hammer as apposed to plate clamp, it did work but I need to get the clamp way working so I can maintain a flat surface.

No, I only re-tightened clamp once at weld temp (or what I thought was weld temp) , I also did not soak (need to learn how to control the heat in my forge) and then removed clamp before it was cool. Weld failed!

Well I think you pointed out enough errors in my method to justify why it failed.

Thanks, the next one will be perfect :D

[Steve Sells]

After first successful weld, I then made the mistake of flattening it quite a bit, and then trying to fold the flattened billet in half, this all at weld temp, however the surfaces were now not so flat and dirty, and even though I fluxed it still did not weld.

flux?> why flux, and WHAT flux did you use? that could be part of your problem

[Blacksmith Jim]

Please post updates on your progress. I am very interested in this. I have had semi success with just quarters. I've done it in both coal and gas forges, using stainless bolts to clamp through a bar. Once I got to welding heat, I let soak a bit, then brought it out of the forge and squeezed it under an arbor press. I hear a kiln is really the way to go, and I'm looking into seeing if I can get access to one.

[jsurgeson]

Steve

Yeah again this is due to inexperience, I used the normal stuff, borax. :confused:

I have since learn't that the trick is just VERY CLEAN flat, matching surfaces, correct temp, just enough pressure, and you will get a good weld. NO FLUX necessary.

A question though, after welding I would want to distort the perfect layered pattern to create something a bit more attractive. after successful welding, can I then forge the billet as you would any other billet? What is the best way to achieve this?

[Steve Sells]

Borax is not a flux for copper or its alloys, wrong temps for one thing. Sal Ammoniac is a good choice for copper, but it is not needed for this application.

Cut not fold, clean clean then clean again.

For patterning, if our welds are good, any repose technique will work, hot or cold! but remember cold it will work harden,you WILL feel it start to get hard, STOP then, do not hammer even one blow more. We must occasionally heat to red, and quench to soften non ferrous metals. Also drilling for a birdseye, grinding slots for a ladder all work. Even twists if you are careful not to over work, remember the work hardening IS a metal stress.

[Dodge]

How did you fold it? When you folded it, did you cut most of the way through one side and then fold? Just folding in half, without relieving the other side, I can't imagine having enough heat time left to close without an "eye" in the fold. Judging from the flow of the layers in the pic it appears thats what happened, but if there is any scale at all now, its not likely it can be salvaged.... Just a thought

[Frosty]

Once it's welded the billet will be as strong as the weakest metal and can be forged or manipulated as you wish remembering the relative weaknesses.

Copper has less strength while brass work hardens faster and more abruptly, both conditions apply.

There's nothing wrong with forging it hot or cold, machining, cutting slicing and dicing.

You can take the first billet and saw it into multiple square bars, rotate, stack and weld again. Have you seen some of the patterned wood used in inlay? All these patterns can be reproduced in mokume gane.

One thing about selecting metals for Mokume Gane. Do NOT put silver next to brass, it's eutectic state produces a melting point WAY lower than you can use. Silver and brass make silver solder.

Fun stuff.

Frosty

[Steve Sells]

How did you fold it? When you folded it, did you cut most of the way through one side and then fold? Just folding in half, without relieving the other side, I can't imagine having enough heat time left to close without an "eye" in the fold. Judging from the flow of the layers in the pic it appears thats what happened, but if there is any scale at all now, its not likely it can be salvaged.... Just a thought

as for salvaging this billet, Cut off the folded part and the remaining should be fine, assuming you don't have scale in the space between the layers...

[jsurgeson]

Steve, thanks for all that info, enough to keep me busy for a while, at least till I screw up again and come back for more.

Dodge, took about 3 heats to complete the fold and 3 more to weld (which did not work) In fact 40% of the weld did work, only the open side of the fold did not weld.

I have cut it in such a way as to hide most of the bad weld to use as bolsters in a hunter I am making. There is more than enough strength in the rest of the weld.

I will post an image when it done, should be by this weekend.

Frosty, no chance on making a mistake with the silver, "TIA" not too much silver available Thanks for the advice.

[jsurgeson]

Well here it is as promised, faulty mokume and all
I managed to hide most of the bad welds, ending up grinding a lot away.

[element]

Great knife, simply stuning colors and craftsmanship, A++.

[Frosty]

Nice knife.

Frosty

[jsurgeson]

Thanks guys, all I need now is to learn how to make some of that pattern welded steel you blokes knock out in abundance on this forum, then I can put some color in my blades. Then I will be happy as a pig in xxxxx  :cool:

[Finnr]

That finished up very nicely!
Finnr

[nelson]

Hi Jeff,
I`ve been reading your thread and the answers regarding your knife. Knife making is another subject within my field of ignorance, but it`s something I`d like to try someday. Anyhow, I read once a procedure where the billet was inmerse in melted brass as a chocolate bar, pulled out and wait a little to let the temp drop a bit to dip it again so the thicker molten brass would completely fill some kind of voids. Did you heat your billet with a torch or in a forge? Must say your knife came out beautiful, and being your first one, wow, don`t ask for more. Nelson.

[jsurgeson]

Hi Nelson

Thanks for the comment about the knife, but to correct you it was first mokume, not knife. I would have been very happy if my first knife turned out like that.

I still have a lot to learn when compared to some of the "bladesmiths" on this forum, I still regard myself as a "knifemaker" as I only started "warming" up to steel recently. But as with you the interest in what is achievable with heat and a hammer, is irresistible.

I think you might be talking about bronze cable damascus, check this tutorial out.

Bronze Cable Damascus Tutorial

I would love to able to make some of that :D

[Dave Budd]

my first thought when I looked at the failed billet was the fact that you have tried to weld copper to copper when you folded it.

When you make mokume you are basically gluing the higher melting point metal together with the lower melting point metal. So in this case the brass melts a bit and glues the copper sheets together. If you have copper to copper then you have no glue in order to fuse the copper to itself you need to heat it until it is about to melt, by which point you have melted all of the brass out.

I always cut and stack with a sheet of brass in between rather than fold, but if you have some thinner sheet brass then folding will still work ok. Or you have to fold it with brass on the outside of the billet (ie inside surfaces of the fold), but then you will most likely stick it to your clamp on the first weld :D

[jsurgeson]

Dave you are 100% right, folding is not the way to go under most circumstance, besides the copper / copper, the surfaces will never be flat and clean, which you generally need for a successful weld.

As you say "cut and stack" is the way to go.

You live and learn

[Kruglik]

Hello.

http://art-metal-kruglik.blogspot.ru/p/blog-page_14.html

[teenylittlemetalguy]

Steve, thanks for all that info, enough to keep me busy for a while, at least till I screw up again and come back for more. :D

Dodge, took about 3 heats to complete the fold and 3 more to weld (which did not work) In fact 40% of the weld did work, only the open side of the fold did not weld.

.

The reason the open side didn't weld is because air got to it before your hammer. That is why a tight clamp is helpful. The oxides that form on the surface will never bond without cleaning. You way be able to reheat and get some of the small crack to close but I have found that a fools errand. You can spend hours chasing it around and still just have junk. If it doesn't look good by the third heat you likely have some issue to address. Good luck with it. It really makes you feel on top of the world when it works.

[Frosty]

Welcome abord Kruglik, glad to have you. Beautiful bearded axe on your front page. I didn't do much exploring, not speaking let alone reading Russian. I look forward to seeing more of your work.

 

Frosty The Lucky.