Don: I think I qualify as a "real Chemist", or at least I have a lot of people fooled...
Actually, SnCl2 is easy to remove, but it is highly unlikely your deposit is SnCl2, but is much more likely to be SnCl4 (Stannic Chloride) which is rather more difficult to remove...
I would recommend either a Caustic cleaner, preferably with some chelate, if your substrate can tolerate that.
If not, probably the only other cleaner which will remove Stannic Chloride is a dip in an Ammonium Bifluoride solution, say, 5-10%. Stannic salts are highly insoluble, and hydrolyze easily to Stannic oxide, which needs either strong alkali, or HF to remove.
Wish I had better news.
Rudy Sedlak
RD Chemical Company
--- On Wed, 8/3/11, Don McFarland <[log in to unmask]> wrote:
From: Don McFarland <[log in to unmask]>
Subject: [TN] Removing SnCl2
To: [log in to unmask]
Date: Wednesday, August 3, 2011, 10:49 AM
Any ideas on methods to remove a tin chloride residue that was found on a FR-4 substrate after wave solder. We have done some good homework to find the source, but we are looking for good and proven methods to remove the residues from affected assemblies.
Any input is welcome.
Regards,
Don McFarland
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