for what it is worth:
Vinigar is Acetic acid (pickle juice)and weak on the ph scale. Phosphoric (H3PO4) is stronger than vinigar, but not as bad as Muratic. Muatic is also Hydrochloric (HCl). Strong acid, battery acid! Way down on the low end of the ph scale. Phosphoric is not that bad, it is in soft drinks and molasses. I have had my hands in it to get a bolt or nut. Rinse immediatly and still protect eyes. Even a pickle hurts if you get poked in the eye with one - anyway -
Muratic acid blows of hydrogen and oxygen atoms as gas and the Chlorine (Cl)bonds to the Fe+ (positiv iron ion). This causes flash rust as water (H2O) easily breaks the bond and causes (FeO2)iron oxide or rust. Muratic will disolve metal relatively quickly and leaves no protective coating. Oxalic acid will actually disolve metal by "surrounding" an Fe+ molecule. Also, the venting is important as you are off gassing free hydrogen and oxygen.
Phosphoric acid breaks up rust(FeO2) and Phospho (H3PO4) to off gas some hydrogen, oxygen, water, and most importantly, leaving Iron Phosphate (white powder coating left on the metal).
Brett
