Bordeaux Powder safe?

Water!  Dodgy stuff!!!  Never trust a chemical with molecular weight of only 18 which manages to remain in liquid or solid form until 100 degs Celsius (at 1 atmosphere of pressure).  Add to that : the solid form floats on the liquid form which is denser at 4 degs C than it is below that.  Two covalent bonds and a suspicious intra-molecular hydrogen bond to boot.  Steer well clear of the stuff, I'd say.