[AT] Phosporic acid and cleaning a gas tank

[Ronald L. Cook]

Kyle,
	I have used Metal Prep, a DuPont product, and similar acids to remove rust 
and prepare ferrous metal pieces for painting.  Flush with water, forced 
air dry and paint immediately.  If left unprotected for very long, rust 
will form as things are really clean.  Maybe you are thinking of 
parkerizing, which is nothing more than black colored rust, I think.  WWII 
gun barrels.  I believe that process takes heat, though.
	I once used some product called rust converter or something on an old 
rusty Ford car.  You applied it on the rust and it turned the rust 
black.  Supposedly you could then paint the part and rust would not 
reappear.  It seemed to work for several years.  I do not think any of this 
is what you were trying to accomplish though.  Clean that tank again and 
slosh it with oil.  That will hold it until you start using it for gas 
again.  Not much help, am I?

Ron Cook
Salix, IA