Removing rust

[Gary Bakeslee]

Has anyone used muriatic acid for the purpose of killing rust on automotive sheet metal parts?   If so how well does it work?
Gary B

[Jeff Wilk]

Gary, muratic acid or sulfuric acid or battery acid.....all basically the same thing with different dilutions works well if you use it correctly and in the right dilution for your application.  In ANY use though you have to be real careful handling it for obvious reasons.....

I use this in plating small parts in my workshop with a Caswell Plating set-up.  After degreasing parts in a hot degreasing bath, the metal will form a surface rust haze in no time.   A few seconds (15-30) in a muratic acid bath (1:20 mix) takes the rust off like magic.  Then a clean distilled water dip, and then into the zinc plating solution.  15 mins later I have a like new zinc plated part.......without the muratic dip the plating would be blotchy at best.

[n2caddies]

I would stay away from it Muratic acid also called Hydrochloric Acid attacks metal eating it away in the little nooks and crannies it gets trapped in. There are many other products on the market today that will do a safer job attacking the rust and not the metal.
Randy

[Quentin Hall]

The best rust remover of all is phosphoric acid. It is a metal conditioner. Ideally you should immerse the item in overnight if it is badly rusted. I have a 1000ltr bath that I drop items in. I buy food grade 80% concentrate in a 20 litre for $90. I dilute it about 7 to 1 with water. It doesn't attack the metal , only the rust. That said do not immerse diecast , cast or spring steel in it. (It will damage these metals). It is very good on aluminium and stainless.
   Prior to paint you should water blast and dry immediately with methylated spirits and rub over with a scotchbrite pad.   

[Tim Pawl CLC#4383]

I recently tried "EvapoRust" available in gallon container at Harbor Frieght and other places. It is endorsed by Rick Dale from the show "American Restoration"    , supposedly environmentally friendly (Beet juice?)   . Amazing results on bolts nuts and brackets imersed at temperature above 70F.   Says for sheetmetal to soak rags and place on sheetmetal haven't tried that but product is amazing overnight results and reusable.  When I think of all the time I have spent over the years on wire wheels, blasting, and chemicals...this stuff is effortless.  Trick is warmer is faster.  Tim Pawl CLC#4383

[Fred Pennington 25635]

Cheep and easy rust remover is a  50/50 mix of white vinegar and water.
Just soak a few hours or over night for the tough stuff and rinse off.

Fred P.

[66 Eldo]

What type of acid do carburetor rebuilders use? Whatever it is/was, it is now illegal in CA (of course) and would make an old carburetor look new. I seem to remember it being muratic acid but not sure as that would not align with an earlier post here of damaging metals.