>I don't think it is a problem for tinning the board.
Paste with an acidic flux isn't a problem for tinning. Zinc Chloride
can be washed off a board the same way Ferric Chloride can after
etching. But for SMD work, where joints and components are involved,
it's probably not the paste to use. However, there are plumber's pastes
with non-acidic fluxes, at least so they claim. Here is the MSDS for a
lead bearing plumber's paste with claimed non-acidic flux;
http://www.laco.com/pdfs/MSDS/SolderBrite_50-50_9_25_98_03_10_04.pdfHere is one for a lead bearing paste with acidic flux;
http://www.palomar.edu/ehs/Facilities/Plum-Loy%2050-50.pdfYou can go to www.kester.com and view the MSDSs for real SMD solder
pastes.