If heavy coat is required that solution should be prepared with water and not with alcohol. Mixture of boric acid, borax, and water brought to boil and used hot. Solution solidifies when cold and should be reheated to be useful. Addition of phosphoric acid is beneficial, but not necessary.
Interesting how methods parallel each other. Change that phosphoric
acid to sodium phosphate, and you’ve essentially got prips flux… I
don’t know, but I’ll bet that upon heating, the phosphoric acid and
sodium phosphate might offer somewhat similar functions… Anyone
know?
Peter