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Justin Chenault

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So I am working on a matching pair of fighters for a customer who wanted mokume gane bolsters ( no biggie I could make some quarter mokume) and have been reading up on Solid State Diffusion Bonding (SSDB) of metals and it got me thinking.


The temps/time reccomendations seem like they are all over the charts but the most common being 100* below the lowest melting point alloy then soak for 5-8 hrs


Also the pressure seems to be relatively loose since no one seems to give an actual # for it


So I have a few questions for the Mokume experts.


1: Am I right in thinking the SSDB is a much stronger and more repeatable method than the typical " wait until the billet looks wet and squeeze it method"?


2: My alloy combo is going to be 360 brass/ copper my temp/ time was going to be 1700* @ 8 hrs. Does this seem about right?


3: Pressure is going to be applied by a set of pressure plates torqued a high as I can get them does this seem like it would be enough?


4: Lastly I was wondering on the quality of finish on the pieces for the bond to work as efficiently/completely as possible?


Any insight would be appreciated as I would like to make some really nice mokume for this set.


Also sorry about the long post guys.




Edited by Justin Chenault
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Well I fugured this would get a little more attention than it has but I figured I would update it anyways.



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this is the my first attempt at solid state diffusion bonding of nonferous metals it seems to have worked well


Specs & process:


18 layers of copper .042 thick


17 layers of brass .015 thick


temp - 1675*


time - 9 hours


pressure plates torqued to 90 ft lbs


placed into a stainless foil bag to keep out O2


pulled out of kiln and clamped tightly in vice until cool



stack after SSDB


copper .037 thick


brass .02 thick


It seems like some of the zinc diffused into the surrounding copper during the soak and there were also a ton of crystals forming inside the stainless foil bag I put it in.

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Hey there Justin,

That is a great looking billet. When I was exploring Brass and copper Mokume My research on the Phase diagrams led me to a temperature of 1500F being a little safer. The danger is The formation of Eutectic between any of the metals present which is the lowest melting point possible between two or more metals. The Zinc soaking into the copper is really the formation of Eutectic alloy which given enough time and temp will convert the entire billet to a puddle even though the temperature may have never exceeded the melting point of the original alloy and copper. 1500F is a much safer temp for that combination and should prevent Eutectic cancer from propagating throughout your billet or fuzzing your bonds. Looks like you lucked out though I suspect you did not run as hot as you think. If it were me doing it at that temp I would have ended up with a bag full of liquid. Clamping it while it cools is a good idea. Those to metals bond easily and strongly.



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So this is my first try at a larger sized billet of mokume gane with new materials.


I decided to try a new method I have read about called Solid State Diffusion Bonding ; essentially it consists of soaking the material at just below melting point for 6 -12 hrs


It seems to have worked quite well the bonding went great and now I just need to work on getting it patterened and worked down.






let me know what you think I will try to update this thread with pictures as I get it worked down

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Wow now thats a huge chunk of mokume ! Looks good i can't wait to see it finished

A bad day forging... is still better than pretty much anything else

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Thanks for the tip on temperature I will use it next time and bump the time up a little.


I was using my Evenheat kiln and it has been checked within the last 6 months to be within temp range so maybe I just got really lucky.


I am going to go to a friends shop who has a press later this week and hopefully start to pattern the billet I am aiming for 2 sets of bolsters 3/8ths x 1.25 x 1.5 hopefully there is enough material if not I will make another billet.

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You know mine could have been over fireing It was quite awhile ago. But the numbers came from paper so I still think 1500F is a good temp. My cycles were about 10 hours and the bond was great.

I love those big chunks, keep updating the thread.


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yes, that is a lot of mokume. I have never done more than a stack of quarters, and often had issues with working it down into bolster or butt cap material. Strangely, for the first few abominations of steel that I called knives, I made quarter mokume for fittings. Haven't tried the real stuff since.


Thanks to Patrick for the info in the other thread about diffusion and change in melting points.


want to see this thinned and patterned. Looking good.


please visit my website http://www.professorsforge.com/


“Years ago I recognized my kinship with all living things, and I made up my mind that I was not one bit better than the meanest on the earth. I said then and I say now, that while there is a lower class, I am in it; while there is a criminal element, I am of it; while there is a soul in prison, I am not free.” E. V. Debs

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Thanks guys I am hoping I can squeeze 2 sets of bolsters from it and have some to play with afterwards.


Sorry bout that Patrick I started the other thread when I was phishing for info but since I had something to show for it I figured I would put one here.



hoping my broken ribe are felling better soon so I can get this worked down



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So time for an update I got some patterning done I went with a ladder pattern.




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Josh I have no idea how much it weighed. As for equipment I used a Evenheat kiln for my heat source and some clamp plates I made for pressure.


I had a few delams during the patterning process but nothing major I think they were from working it down too much in the first few cycles between annealing cycles



So let me know what you guys think

Edited by Justin Chenault
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Hey no problem Philippe I have no secrets anything I learn I am always willing to share the process that has worked for me as so many people in this Industry have been so willing to share info and help me I feel like it is an injustice to them not to share things I have learned through trial and error so as to make this easier for others to figure out.

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  • 2 months later...

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