From a vendor on ebay...
Sodium Silicate, NaSiO3, solution used to deflocculate or disperse clay
slips, slurries, or glazes.

Perhaps it globs up particles so they sink or otherwise get out of the
way. Just using washing soda, the solution got pretty opaque...

Must remember to NOT use stainless steel cutlery next time. So THAT's
what the yellow stuff was... /mark


wrote:
Well maybe to reduce pitting. I said undercutting because I believe
sodium silicate is used when etching to reduce undercutting. I have no
idea of why it does that, but if it tends to reduce the etching action
where the etching is beneath the resist, I think it would also reduce
the etching action is pits.

I will do a little googling and see what I can find. I think the name
used by etchers is dragons blood, but am not sure.

Dan