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BlueDogKnives

Mokume Gane in my heat treat oven?

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Howdy folks, I've looked around and haven't been able to find any info, hence my post. I'm looking to use Mokume Gane in my knife making, but the prices are currently prohibitive.
 

That being said, I do have brass from reloads that are worn out, and instead of throwing them away I'm thinking about melting them down to make my material. I have two graphite containers for casting bars, but no furnace or hand tools to heat up the metal and give it the proper twists and twirls and whatnot.

 

My question is can I line up the brass and copper in the graphite bar maker, place it in my heat treat oven (Evenheat KH414), and take it right up to just above the melting point to slump it all together? Or is this a good way to blow up my heat treat oven and destroy my $1300 investment?

 

Thank you for any help or suggestions, they are much appreciated.

Sam

 

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Dear Blue Dog,

It strikes me as a good idea but I think there are some problems.  First, the melting point of brass (85% Cu, 15%Zn)(cartridge brass may be different) is about 1652-1724* F.  The melting point of Copper is 1981* F.  So, I think that you would have brass liquid before you got the copper soft enough but it is possible that if you got it right to the melting point of brass the copper might be soft enough for a bond to form but you would have to be very careful about your heat control. 

A more significant issue is that the Evenheat KH 414 is rated at a maximum heat of 1650* F..  So, at your maximum heat output you would be right at the melting point of brass and 331* below the melting point of copper.  It might work but you are pushing your oven to its maximum.

Also, working with metals at or above their melting points is DANGEROUS!  You need to be very careful and use full PPE and appropriate tongs to handle the flasks, crucibles, or molds.  I cannot stress this enough.  I don't want to frighten you but this is as serious as a heart attack.  Making a mistake or being careless can result in life changing injuries.  I won't say "don't do it" but be VERY careful, particularly if you do not have experience with molten or near molten metal. 

Good luck.

"By hammer and hand all arts do stand."

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Mokume Gane is a SOLID PHASE WELDING process; you don't "melt"  any of it!

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George, I appreciate the feedback. I have the knifemaking version that's rated to 2200°F, so that was a consideration but not a heavy concern for me. I just cooked a rasp file at 1800°F yesterday, and regularly run in the 1650-1700 for O1. I have zero experience with casting or molten metals, but my thought was cook the whole "build" around 350 with the door open to remove any and all moisture, kick it up to 1850 to melt the brass and soften the copper, let it stay there for about 30 mins, and then kill the power and let it cool on its own so I'm not sloshing around and metal. Mostly because I have a cheap set of tongs that came with a small crucible I ordered from Amazon for some silver casting I'm planning on doing. The only other items I have are blacksmithing tongs, and I'd be way to concerned about the slipping on the graphite.

 

Thomas, I appreciate the info, and I'm aware true Mokume Gane is made in a process similar to Damascus. However, I don't have a clean enough or hot enough (reliably) forge to do that. I realize it's not *true* Mokume Gane, but it would hopefully look similar and look good. Or it might be a waste of some scrap I have laying in my shop that would be dumpster fodder anyhow.

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I dont know how you missed an entire section with over 1,000 posts but I will relocate this to the mokume section for you

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3 hours ago, BlueDogKnives said:

I realize it's not *true* Mokume Gane, but it would hopefully look similar and look good.

I've seen "cheater" Mokume Gane done this way before. You're basically brazing; you'll still want to clean the materials and use an appropriate brazing flux or the brass isn't likely to wet the copper. You don't get out of the cleaning requirement by not welding! ;) You also need either very good fit up or a fixture (that can take the temperature!) to clamp everything together to ensure good contact.

It looks like thick sections and bolts of Austenitic stainless steel would work to hold things in place if you were to have interest in trying a fixture:

https://www.nickelinstitute.org/media/1699/high_temperaturecharacteristicsofstainlesssteel_9004_.pdf

The contrast can be less distinct if you have appreciable zinc (or whatever is in your cartridge brass) diffusion in the copper, but the examples I've seen were a reasonable approximation of Mokume Gane. I don't know how you would get an appreciable pattern if you don't have a means of working it hot. Perhaps make a way to pre-bend all of the sheets the same way repeatedly and braze them already bent? Any cuts through this would provide a pattern that would depend on the bend pattern. Of course, fit up would be complicated by this approach, as all of the bends or curves would have to be high tolerance to avoid gaps. 

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You may want to look into some of the threads on using US "sandwich" coins to make Mokume.

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Blue dog: What you describe has little resemblance to Mokume Gane.

It's easy enough though, I've done it in my propane forge and one of the guys in the club has gotten very good at it, better now that he picked up a temp controlled kiln. 

You need a clamp. My first one wasn't strong enough and warped at heat, it was two pieces of 1/4" mild steel a little larger than a stack of quarters with matching holes drilled in the corners again to clear the quarters. I flattened the quarters on the anvil, I'll use a flatter if I do it again. Then I sanded the quarters shiny, degreased them with alcohol and stacked them in the clamp and cinched the bolts TIGHT.

I brought the unit to heat gradually in the forge retightening the bolts twice as soon as the quarters took on a "sweating" appearance I removed it from the forge and set the welds with a hammer. I had to use a kiss block to keep the bolt heads off the anvil and another on top for the same reason. when cool I removed the bolts and billet.

There are more complicated and reliable methods but in essence there are simple rules, Clean, clean CLEAN. Pressure and Heat. Jim Binnion is a past master of mokume and owns Mokume Gane dot com. 

One last tip, Do NOT mix brass and silver, they form a eutectic alloy with very low melting temps in the mid hundreds F. 

Frosty The Lucky.

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