Hi everyone,

I'm wanting to improve and solidify (no pun intended) my pattern welding and mokume gane skills. I've done a hand full of successful forge welds and one small piece of mokume gane.

I'd like to make two (not overly large) belt buckles as vehicles for this learning curve, one pattern welded/damascus steel and one mokume gane (most likely copper and brass). I'm happy to work my way up to these projects (and knowing me, I'll only get to making them in about a year's time!) but it's good to have a goal.

My plan is to make some square cross sectioned billets, then twist, forge slightly flat and then grind even flatter to expose the pattern. Provided that I get successful billets, I'm confident I can do the rest of the work in steel, but what are the likely issues with mokume gane. I'm guessing delaminations at the twist stage and the forging flat stage could be an issue? With copper and brass, would I be better to try to forge it cold and anneal often, or keep it hot to encourage the metals to weld/stay welded?

Would love to hear some real-world-experienced opinions.

TIA!

Jono.

I have only tried it with coins and found it surprisingly easy. I wrapped with tie wire and light welding taps. A little practice will make you a pro and would love to see some photos. Good luck

It's easier to use relatively thick layers making mokume gane, there is less lateral stretching so it is less likely to shear between the layers. Delaminating is harder to avoid when forging than twisting, you want to do it at close to the diffusion welding temp (color) you made made the billet. Don't forge it too often or the two alloys will diffuse into a single brass alloy. 

Don't try making mokume with silver and brass / bronze in contact or they'll form silver solder and melt at a very low temperature.

There are lots of books available about mokume gane. It's a wonderful craft and venue for expression. 

Frosty The Lucky.

I have forged thousands of pounds of mokume in the last 15 years, usually starting with blocks much bigger than what you are working on. the key to successful mokume is keeping the surfaces clean prior to bonding. If you do that, then run a bonding cycle that is effective, meaning long enough and hot enough for the materials in your billet, you should have very good success. As you work the billet, take time to grind out layer separations and cracks. When twisting, I always forge to an octagon first, then twist, then forge to final size and shape. This minimizes the risk of getting corners that tear apart or form laps during later forging. I don't do much cold work. You can do a little bit, but brass and nickel silver (which are common elements in the billets I'm forging) do work harden fairly quickly so if you were going to do much cold work you'd need to anneal frequently.

That octagon tip will be very useful, I'm sure, with mokume gane and with damascus. Thanks!

Again, my time thinking up these projects is far greater than the time I actually spend in the shed so 4 months later I'm no closer to actually doing any of this! 

As they say, "Life is what happens while you're busy making plans!"

Can you show us some pictures of what you've done Patrick?

Sometimes when I read your posts I catch myself thinking what's he talking about now? Then I read more, maybe a couple times and find nothing to disagree with. You're rapidly becoming someone to sponge as much info from as I can. 

So, how about a look at your mokume gane, tools, clamps, wraps, etc. Do you use mild steel, something higher alloy or? Do they have thick plates and bolts or are they cam locked? Electric, gas or? furnace / kiln?

Please.

Frosty The Lucky.

Frosty- The mokume I forge is all bonded by Mike Sakmar, who is using the methods described in the book "Mokume Gane in the small Shop" by Steve Midgett. A digital copy of that book is available free on Mr. Midgett's website. There are several methods used in the book. The method used for the billets I work with is to clean the pieces to be bonded in a strong acid, rinse in a solvent like acetone, then layer up the billet. From the point of cleaning onward the pieces are handled with gloves to avoid getting any finger print oils or other contamination on them. Once the stack is complete, it is wrapped in stainless heat treat foil. It is has been many years since I've visited the shop where this happens and I don't have pictures of this part of process, hence the reference to the book above. If I remember correctly, I think a small amount of charcoal may be added to the foil package to serve as an oxygen consumer, but I don't recall for sure. Once the billets are wrapped in stainless foil, they are clamped between flat steel plates with bolts at the corners. They are put into electric kilns and heated to the desired temperature for a time commensurate with the size of the billet, but usually an hour or two. Bonding temps are picked based on the alloys used, but will be a little bit below the melting temp of the alloy with the lowest melting temp in the billet. After the bonding cycle is done, the billets are removed, clamped in a vise and the bolts removed. The foil wrap is ground or machined away leaving the billet sides smooth. That is what I get. (picture below).

My forging is done almost exclusively with flat dies, and all under my 300 # Bradley. Sizes I make are dictated by my customer, (Mike Sakmar) who owns the material and pays me to covert it to his desired sizes. Common sizes are 0.230x01.675 flat (twist before flattening) and a variety of octagon sizes. Occasionally there will be some larger flat cross sections like 5/8 x 2 1/2. Most material is twisted to generate the pattern. When some other pattern like raindrop or ladder is desired, I forge to a specified flat bar size, send the metal back to Mike who machines in the desired pattern with a ball end mill, then it is sent back to me for forging to final thickness. I've been doing this work for probably 16 years or more and most of that time the twisting has been done by hand. A few years back I did add a twisting machine to the shop, which is simply a very old (line shaft driven) pipe threader modified to take the flattened end of an octagon in the "chuck end" of the machine.  Mike does sell his material to anyone, though many of his customers are from the knife making and fidget spinner community. You can google him to find his website.

Because these are copper alloys, there is no need for a hammer as big as mine, it's just what I have. I will say though that I much prefer a hammer to a press. Presses are much slower than hammers and though they'd work fine for the initial break down of the billets, they pull heat out of the work too fast for effective forging of the thin flat bar and plate often make and they are just too slow for drawing out small cross sections. The 0.230 x 1.375 flat size I usually forge to 3/4" octagon before twisting, but I do that using die bites that are about 1/2" long. That is  a LOT of strokes and most presses a just not that fast. 

Most of the success or failure associated with forging mokume is not in the tooling but in how you USE the tooling. As mentioned, almost everything I'm doing is with flat dies, but how big a die bite you take and how hard you hit the metal changes as the job progresses and if you don't do that right you will end up splitting the billets apart. Describing that detail is pretty hard in text, but the approach is not that different from what you'd used when forging very slaggy wrought iron.

I've made mokume gane and used to discuss it with Jim Binnion on the old Artmetal.list The wife and my wedding rings are simple twist pattern mokume made from the gold from one of my Father's opal ring and one of Mother's white gold pieces of jewelry, red gold from one of Deb's rings and IDR where the Silver came from, maybe a couple of my Grandmother's silver dimes IDK. It had a gold liner from Deb's ring. 

Things like never mix brass and silver are basic metallurgy so I didn't have to learn it the hard way. 

Shearing a billet is the result of misaligned forging forces on metals that are more malleable at forging temp. 

Jim and I tended to disagree a little about making patterns. He did as you do and machined grooves, depressions, etc. and forged the billet flat. I liked the patterns I was getting by forging the textures with ball punches, various fullers, etc. and grinding to expose the pattern. A raindrop or ladder pattern that's machined then forged is very different from one that's forged in and ground flat. Recognizable as similar but not the same. 

I was using different repousse chisels in different patterns to make some really cool patterns. However seeing as I was doing it in my hobby blacksmith and as needed fab shop I didn't have the level of control necessary to make good mokume. (as in properly and uniformly fused consistently.) Judging temp by eye and time with a wristwatch just doesn't cut it. 

It was just too expensive to pursue though a few of the guys in the local club are making some nice jewelry but they bought kilns with ramping controls, etc.

Thomas Powers, I and others used to discuss the similarities between pattern welded iron, steel, etc. and Diffusion welded precious metals, mokume gane. Heck, one of the old Artmetal.list gang, Elizabeth . . . a pretty well known master blacksmith from the Carolinas. Made a mokume Gane billet in a quickly cobbled together clamp in a coal fire. After the second fold and fuse she literally tossed her hammer on the bench and asked us. "Are you bloody satisfied"? Other members of the group sawed sections at different angles, shined them up and etched them. 

The biggest complaint was the clamp bolts interfered with making good strikes on the clamp plates. The billet developed a good pattern if random in a couple non-random ways.

The rest of us "solved" that problem by making blocks with holes for the bolts and heads thick enough to provide solid support. We preheated them so they wouldn't sink the heat from the billet but not so hot they caused squirts. IIRC maybe 7-8 of us metal heads had a pretty good time and you betcha we sprayed molten metal a couple times. Eyeball them gages are like that. We also found a 10lb sledge. (strike your own billet!) was good but 12lb tended to be too hard to control and get even straight down blows.

I made my last few billets under my 50lb. Little giant on flat dies. But again couldn't afford to get good at it and making quarters, nickels and penny mokume isn't very interesting. Except of course how limited the forgeability of nickel let along the alloys in American coins is.

Thanks Patrick.

Frosty The Lucky.