On Thu, 09 Aug 2007 17:13:09 -0700, Grant Erwin
wrote:

Mark Rand wrote:

On Thu, 09 Aug 2007 13:03:54 -0700, Grant Erwin
wrote:


What I'm most interested in now is the use of lead sheet for the cathode. I
have tried this (as I've posted) and it works great, no current drop as I always
used to see with steel cathodes. The lead electrode turns red, so I suspect the
formation of red lead (lead tetraoxide) as opposed to lead carbonate as another
person has suggested. My only reason for thinking that is the color - lead
carbonate is white, and of course lead tetraoxide is red, and my electrode
turned red, not white. I don't believe that much lead is going into the bath,
and of course I wash my hands after handling it.

I wish I knew more chemistry sometimes.

Grant Erwin
Kirkland, Washington



'twas me Grant. In my case I was using washing soda solution (sodium
carbonate) as the electrolyte. The growth on the cathodes was white, which is
why I assumed lead carbonate. I assume that you are using a different
electrolyte... What?

I could live with lead tetroxide as a contaminant... Wash it, dry it, grind it
and use it when scraping, It would save me the cost of buying more of the
stuff :-)


Regards
Mark Rand
RTFM

Yes, I was using washing soda too. On my electrode, just above the
water line, there is some crusty white residue. This could be washing soda, or
it could be lead carbonate. The rest of the electrode is a smooth brown color.
That's what I thought might be red lead.

Grant


Hmm, same setups, different results, maybe current density and electrolyte
concentration play a part. I guess it can only be lead oxide or iron oxide. I
don't think I'm going to stop using lead cathodes in either case. Neither the
carbonate or the oxide is soluble and any build up stays in the tank.


Mark Rand
RTFM