I'm not quite sure I follow you here, John. Did you mean to say mixing
the Pt and Pd solutions together with the Ferric Oxalate, and then
storing that?
I get my Pt and Pd solutions in aqueous form from Bostick and Sullivan.
Since the Pt solution is super-saturated I like to heat it to make sure
any crytals which may have formed at room temperature are dissolved.
Also, as I mentioned, the ratio of metals to ferric oxalate is related to
the temperatures of the solutions.
Could you elaborate a bit more on what you meant?
David