[TheForge] Mokume Gane

[Andy Vida]

gblacksmith wrote:
> 
> Hey Mokume-makers:  I have been experimenting with mokume using brass
> and copper and while I have been able to get the initial billets to
> join, they have all delaminated in the forging process.

	In that case you actually have not gotten the layers to 	
	join, or the diffusion was only superficial.  If the welds
	are good, any failure in the material should not correspond
	to layer boiundaries, except perhaps by fluke.
> 
> The billets were initially made of 1/4" brass and copper strips 2" in length for an overall thickness of about 1.25 inches.  I cannot be sure of the brass alloy but the copper is electrical bus bar.

	Were the surfaces clean?  How
	long did you leave the stack at temperature?  These are all
	factors.  You don't have to use a torque plate, but it can
	be helpful both in terms of best assuring good surface
	contact and for heat capacitance.  Did you have temperature
	control on your furnace?
> 
> I joined them in my gas forge using torque plates and a closely fit steel box frame   to hold them together for the initial bonding. 

	Perhaps you did not leave the stack at temperature long enough.
	Time is an issue.

> after the brass and copper could be scratched with a steel pick, I took them out of the forge and squeezed then in my #5 fly press until cooler.

	If you did this hot, it may have been a contributing factor.
	Copper doesn't do so well in hot forging, and most brasses 
	and bronzes are even worse, though there are some
	exceptions to this.  If the billet was way hot when you
	put it in the press, you could easily have sheared the welds,
	expecially if they were tenuous to begin with. This is also
	something one must be careful of when putting a freshly welded
	steel biillet into a press for the first time before the welds
	are REALLY stuck, which I learned the hard way.
> 
> The atmosphere in my forge is not oxygen free as I had to leave the door
> open to accommodate the torque plate handles. 

	I'm not a mokume guru, but I don't think this should be a great
	problem since you used a torque plate, which should keep the O2
	mostly out.

> I used paste of yellow ocher to keep the copper from sticking to the steel
> torque plates.

	That should be just fine.  You can also use carbon soot from an
	Oxy-Acet torch or China white.

	Hopefully Jim Binnion wil pipe up here.  He's the Mokume King and
	does absolutely incredible work.

	-Andy