You are trying to make Ferric Oxalate from scratch? I've always been told this was a difficult process because of the compound's instability. There are detailed instructions at http://e.neilsen.home.att.net/FerricOxalate.html I've read again and again that this was something to buy rather make because of the time it takes and that the relative cost savings is neglible.
Did I misunderstand your question?
> Date: Mon, 10 Nov 2008 15:59:27 -0500
> From: email@example.com
> Subject: ferric oxalate
> To: firstname.lastname@example.org
> I'm trying to mix up some ferric oxalate, from powder, for use in pt/
> pd printing. Can someone detail their formula for me, for mixing
> this thoroughly?