Mokume help

[freeman]

So I just racked up another abject failure attempting to make a mokume billet from iron, copper, and brass. Here's the results:

 

 

and a view of my torque plate:

 

 

So here's what went down:

 

I cut up a bunch of scrap stock I had lying around into 1 inch strips. Each strip was then thoroughly sanded, washed in a light detergent to remove any residual oils, and then rinsed thoroughly. Once rinsed each piece was dried with a paper towel and then stacked over by my wood stove for further drying.

 

Once I'd gone through the entire stack I loaded them up into the torque plate and used a bench vise to compress the stack before tightening all of the bolts down.

 

I then fired up my new (half finished) gas forge under the assumption that it should have no trouble reaching temps required for this kind of work and I tossed the plate in the fire.

 

As soon as the plate started showing color (dull red) I started rotating it to try to keep temps even. I'd spin it 180 degrees on one turn and on the next I'd flip it.

 

The entire time I'm eyeballing the stack waiting to see "sweat".

 

When both plates and the stack had reached a medium orange color I saw the stack slip a bit. I figured surely the brass alone couldn't take much more of this and that had to be the sign I was waiting for so I took the plate out, set it on the anvil, and gave it a firm whack. Imagine my surprise when this resulted in an immediate (and spectacular) spray of molten metal all over the shop. Miraculously neither myself nor anything else was set on fire.

 

I figured that was probably enough with the bashing so I fished the now cherry red stack out of the plate and tapped it a couple of the times on the anvil, at which point it crumbled into individual slabs. In celebration I threw my hammer across the shop, turned the forge off and stomped into the house.

 

So, any ideas where I screwed up?

[Steve Sells]

ok starting possabilities,  Iron in the mix makes it hard to do.  Assuming you have done this before,  drying over by the wood stove could have deposited some smoke residue on the plates.  hitting too hard and too soon forced the brass out as its the lowest melting point of the metals you used.  there is a start.

 

I like your torque plates, they look the same as I use. I smoke them to prevent the billet from sticking to it, as well as a layer of newspaper.  What did do you prevent oxidation in the billet I dont see any wraping ???

[freeman]

Short form: I have absolutely no idea what I'm doing.

 

I'm basically mimicing two ukranian dudes I saw on youtube that welded up a mokume billet using a similar rig with no visible flux or any other obvious oxidation preventative. I (naively?) assumed they were banking on a seriously reducing atmosphere in their forge to pull it off but all of this is guess work on my part.

 

My takeaway:

 

1. mixing grossly different metals (iron, copper/brass) in a first attempt was clearly a mistake.
2. it sounds like I may need to do something to help prevent oxidation in the billet
3. I jumped the gun pulling the billet out of the fire

I'll do another run maybe tomorrow night taking these points into account. Thanks for giving me something to go on!

[Steve Sells]

no flux,  but we do sand and clean, do NOT use soap and water,  read more first or you will fail again.

[Stephen Olivo]

use the vice next time to provide easy steady pressure this will usually decrease the stack by like 1/4 and then let it cool a bit in the vice (when tight)  put back in the fire and bring it up to temp again and repeat.  Make sure your layers seem pretty well bonded before you take it out of the plates and try and forge it.  Though if the metals are two different forging may not be an option.  Presses are great for this kind of work but vices are just a simple screw press.  Reading up on this will help.  I can see by your plates you probably squished out all the copper or brass that would have bonded the plates together.  I have done just say 7 or 8 billets using coinage.  No flux or anything to keep oxides down.  Blue painters tape around the billets sometimes and always between the billet and the plates to aid release.  Usually the first 2 or more heats were in the vice only and then forged over the anvil.  Each time some layer would come apart it would go back in and get carefully squished back together.  I am in luck and my friends propane forge goes right to the point you want it at and not really any higher.  It looks like the temp/time was good just probably hit it to hard while the layers were liquid.  Try it again and be gentle with it. Hopefully my limited experience helps you :D

[Chinobi]

i am in a similar expiremental stage with the process so apply salt as needed:

 

i dont know what your setup is but while you rotate and flip the billet in the forge make sure you do not actually remove it from the fire until you are convinced that the plates have bonded.

 

from the oxidation patterns in the first photo it almost looks like the plates were not totally flat, there appear to be areas where they were almost bonded and other areas where the oxidation is almost complete.  i have seen similar patterns on my pieces and when closely inspected they were warped.

 

something i learned when i learned to forge weld is to consolidate the stack gently, rather than sledging it together with a lot of power.  this will also prevent liquid and near liquid phase metal from getting squished out from between more solid layers.

 

try again without the iron until you get more of a feel for the process, starting with a simpler combination between two metals makes learning faster and less frustrating.  plus, when you do get a bond on an iron/copper/brass stack the iron will make it more challenging to actually forge the billet because it is so much harder than the copper and brass.

 

definitely read through some of the other threads in the section as well, they hold quite a lot of useful information!

[Albert A Rasch]

Freeman,

 

Link:http://www.mokume-gane.com/Papers/SantaFePaper.pdf

 

"After thorough mechanical and chemical cleaning, the metal
sheets are stacked and bound between iron plates that have been coated with a
resist to prevent the laminate from sticking to them during the diffusion process.
The stack is placed in a forge and heated until the metals in the stack begin to
“sweat”. At this point some of the alloys in the stack have reached the
temperature where some liquid phase is visible on the edges of the stack. The
stack is quickly and carefully removed from the forge and “lightly tapped with a
wooden mallet”. It is then hot forged to improve the bond strength and reduce its
thickness."

 

Notice the "lightly tapped' part there.

 

It reminds me of forge welding, Every example of the process starts with modest striking, reheating, striking, reheating, ad nauseum, until it is complete. I would extrapolate that the "It is then Hot Forged .." Mean it is hot forged after several heat tap squeeze, heat, tap, squeeze, iterations to make sure the welds are complete.

 

I'm reading up on the process now, and I don't see (yet) any mention of any kind of flux... I'm already contemplating a super-saturated solution of borax. I'm wondering if that might help in avoiding the delamination problem. I'm guessing there might be a reason for no flux, but I can't find any references.

 

13:18 hours: I stand corrected. Steve Sells sez, "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." http://www.iforgeiron.com/topic/10503-help-bad-bad-weld-on-my-first-mokume/

 

Anyhow, I hope this helps!

 

Albert

[freeman]

Albert, thanks for the link!

 

I ran another test billet with the iron removed (brass + copper) and managed to get the stack to bond. This time around I used a vise to compress the stack instead of hitting it with a hammer. Unfortunately while I was experimenting with working the billet it sheared when I tried to work it cold. I speculate that I had not sufficiently consolidated the stack before I started tinkering with it. Differing working characteristics of the two metals used may also be to blame. In any case I'm slowly getting closer to success. If I come across anything else noteworthy I'll post here.

[Chinobi]

cold work can separate even properly bonded layers if it is work hardening and you are hammering on edge, but it will certainly also point out the layers that didnt bond :)

 

got any pics of the run?

[freeman]

I didn't take any pics of this batch unfortunately. I ground the billet on all sides looking for obvious delamination and didn't see anything and had worked it hot for a couple heats, again with no signs of delamination.

[colorblind72]

I have a slight obsession with Mokume.

I have had a very hard time with brass added billets.

The zinc in the brass makes bonding very difficult.

I have found the easiest way to practice is use $5 in 50 cent pieces.

Clean thoroughly and put in your torque plates, and fire.

I fire using a thermalcouple to read temps.

1830-1840 is your range for copper, brass, nickel silver billets.

Otherwise you do have to eyeball it and look for the sweating of the billet. 

A tap or series of taps with a wood dowel hit with a hammer is how I do it.

Cold working is great but anneal often.

reduce by a third and start patterning.

The top image is the best copper, brass, nickel bond I've done and the bottom is coins.

The brass billet was done in a steel box with cardboard in it to burn out the oxygen and minimize scale then pressed in a large screw press.

 

[Chinobi]

very nice work colorblind!  what are you using for a heat source? sounds like a kiln?

[Old N Rusty]

http://www.amazon.com/Metal-Techniques-Craftsmen-Methods-Decorating/dp/0385030274  This fine book covers MOKUME , and many other things to do with metal.

[Chinobi]

any thoughts on why the old version is reviewed so highly and the new version so blandly?

http://www.amazon.com/Metal-Techniques-Craftsmen-Methods-Decorating/dp/0709107234/ref=rec_dp_2

 

do you have a copy? is it something worth pursuing?

[Francis Trez Cole]

I personally do not use a Torque plate I use copper rivets and just rivet the bundle tight. have not had a problem and I like using my gas forge as well I just put a piece of Kalwool on the bottom to catch drips and protect the lining.

[Chinobi]

what rivet layout do you use, just the 4 corners? does that area end up getting cut off/worked out or do they just kinda blend into the overall look and not show up as a big copper dot?

[colorblind72]

I'm sorry, I didn't see the question to me come up.

I have had rare success with brass. 
When I did have success I did it in a steel box with cardboard under and above the billet.

This allowed the oxygen to burn out and put a layer of carbon between the top and bottom of the box.

I use a pyrometer and if I remember correctly the # you're trying to hit is 1840 degrees.

I hold for 15 minutes and then run in a press.

I have done the traditional method with torque plates, in a charcoal forge with copper, nickel-silver, and steel never iron.

If you use a gas forge it needs to be fuel rich to protect form oxidization.

I don't use flux but have seen people do it with success.

I have never used a kiln, 

The kiln process uses a much lower temp with a longer time inside a stainless steel bag with charcoal in it.

The bag has charcoal in it to burn the oxygen off. 

As I understand it you are trying to get electrons form both types of material to switch places to create the bond.

If you slightly melt the material and make an alloy you will see a fuzziness on the edge of the bond.

Personally I like both looks.

http://www.aescustomknives.com/docs/tutorial12.htm

This is where I learned the box method.

I learned the regular method from this book.

http://www.guyotbrothers.com/jewelry-bookshelf/mokume-gane-comprehensive-study.htm

I don't check in here a lot but if you have any questions.

please feel free to email me at colorblind72@comcast.net.

[Chinobi]

Thanks for the reply Colorblind :) good info!

 

i have seen Ariel's work and it is truly stunning.

 

i envy your copy of Midgett's book :) im almost fed up enough to buy the German translation for 40$ and beg/plead/pay my girlfriend to read it to me  :D

 

i bought Ian Ferguson's book, its much more brief, but it covers the basics pretty well.

http://www.amazon.com/Mokume-Gane-Jewellery-Handbooks-Ferguson/dp/0713661569

[colorblind72]

That would be a very kind thing for your girlfriend to do.
The book is comprehensive and unfortunately there is not a lot of video of the process on Youtube

There is some though and you can get some decent info from it.

[Francis Trez Cole]

what pattern do you want to add to the piece that is where I add the rivets I like copper. 

[CTBlacksmith]

Whenever i make billets i do it in a stainless steel foil bag with charcoal inside. The billet is compressed between the torque plates as tight as they can go. For copper and bronze i heat to 1625 for ten hours, take the bag out, cut it open, tighten the bolts as far as they will go again and let it cool to room temp. I have always been told to cut the edges off to get rid of delamination and then reduce the billet to 1/3 the original thickness with hot forging while the billet is at a black heat. Then cut into the pieces you want and roll out or forge and pattern to your desired results. And i've always wet sanded them down to 220 and rinsed in distilled water, never with soap or any detergent. The book Mokume Gane in the Small Shop by Steve Midgett is excelent. He actually gives you plans for making a small kiln out of two soft fire bricks that you fire with a torch.