Hi Folks, I'm stumped! I'm trying to do something relatively simple
I've done in the past, but am now having complications.
I have some 22k/sterling mokume gane sheet. I'm trying to lightly
etch the silver content with ferric nitrate to provide a texture
contrast... lightly frosted white next to the highly polished 22k
gold. A very elegant look when it worked before.
Now, on a the last couple pieces, a durable black substance is
developing on the silver. I have tried pickling, ultrasonic and ionic
cleaning and nothing has removed it. It appears that it did etch,
however. I mixed a fresh, stronger batch of acid using distilled
water. I have used metal from two different batches of mokume. The
last one was in the bath for only five minutes, and the black residue
was already forming. I put my vibrating tumbler on top of the
assembly containing the bath in order to provide some agitation.
Does anyone have any clue what is going on here, and/or how I can
avoid the blackening and just get a nice clean etch? I don't have any
nitric acid at my disposal at this time.
Thanks in advance!
Sebaste Studio and
Carolina Artisans' Gallery
Charlotte, NC (USA)