phosphoric acid for rust

[z_pyro]

i've heard phosphoric acid can get rid of surface rust. where could i get some, what's the average price, and how easy is it to use?

i have a tiny bit of surface rust in my spare tire well, under my battery tray, on my roof and a bubble above the gas cap.

[hmsports]

Use Naval Jelly (available at any hardware store) to remove rust - then use a good primier. It is MUCH safer than phosphoric acid. Or use a wire brush brush and some sand paper.

Phosphoric acid is extremely hot - and it will burn quickly. My father-in-law (a professional painter) has used it many times on big jobs and he has 'recommended' that it not be used - he has seen too many guys get hurt - including one guy that burn his eyes and is now blind.

That's my two-cents.

[spudz]

I use Oxalic acid to clean rust and aluminum

parts. I buy it by the gallon at paint stores.

It isn't as hot as other acids and works great

cleaning stuff off. You just have to remember

to coat what every your cleaning right away.

[z_pyro]

coat with what? primer? i've heard that primer doesn't really protect against rust.....

[spudz]

The proper way would be with primer then

paint over the top, but if the area isn't

exposed to sunlight much you could get away

with just POR -15 .

I need to repaint my battery tray area

myself, but not until another motor goes

in.

[EScanlon]

ACID IS DANGEROUS! IF YOU DO NOT KNOW HOW TO WORK WITH IT, IT CAN HURT / KILL / MAIM YOU.

Knowledge of how to work with other acids is NOT to be considered knowledge of ALL acids. There are some acids out there that will literally explode in the right atmostphere. If you don't know about it, I wouldn't muck with it.

Acid is one of those items that has hundreds of stories that begin with "If only I had known..." OR "Everyone WARNED me, but...".

I would recommend you get a product called Metal Ready. It is sold by the folks who sell POR-15. It is a ready mixed solution that will both remove rust and pre-etch the metal for any kind of paint, primer, or POR-15 product. I've used it and it works very nicely. It is relatively inexpensive, and if you filter out the gunk, is reuseable. Cure time is not measured in hours but in minutes, and did a superb job on my Gas Tank.

Since the areas you are referring to are notoriously prone to rust, you are better off doing the job right with what others have found works rather than trying to forge a new method. Metal Ready, POR-15 and their Reinforcing Mesh, or plain old Welding New Metal are the best ways of dealing with these areas.

[EScanlon]

Since this forum is hopefully used by many people, I felt it necessary to post the warning.

Acid, like Paint Stripper is an EXCELLENT tool, IF you know what you are doing. But not knowing, and attempting to learn on the job without someone watching over you who DOES know is like packing your own parachute and hoping you get it right.

That you know the difference between full strength and diluted (and I'll bet that the "diluted" was even diluted from it's full Molal solution) is the key here.

I saw a guy who claimed to know how to use paint stripper apply it first to the FENDER of his car, THEN he proceeded to apply it to the hood. While he was applying it to the hood, he inadvertently leaned into the fender with his crotch. 5 minutes later he started screaming from the burning from the stripper. Then he got the lacquer thinner he was using to "cut" the stripper and applied some very liberally to the area in the hopes of stopping the burn. THAT was the completely WRONG thing to do, as he then made it worse. Yes he cut the stripper BUT THE LACQUER THINNER ALSO STINGS ON YOUR SOFTER TISSUES. When I saw what had happened, I grabbed the water hose and doused him. Would you believe the guy was mad cause I splashed water on his fender and hood in trying to put his "fire" out?

Warnings are NOT to stop knowledgeable people from doing the job, they're made to stop people from assuming that it is something they can do with no knowledge.

Just my 2¢

[z_pyro]

Welding New Metal!?

All i have is some surface rust!! I want to stop it before it becomes really damaging, BEFORE the point I have to weld. This car has no penetrating rust that I have found, and I have looked thoroughly. It just has some SURFACE RUST under the battery tray, in the spare tire well, and a little bit on the outside.

[2ManyZs]

Probably the best way to get rid of light surface rust is sandpaper and a little "elbow grease". In other words, sand it, scuff the surface, use a self-etching primer on the bare metal, use a primer sealer over it and re-paint the area.

Use sandpaper, wire brush to remove any scaling, scotch brite pads or anything abrasive to remove all the loose paint and rust. Media blasting is another alternative for larger areas. Then be sure to coat it so it doesn't rust again.

Chemical strippers have their uses, but not on spot repairs and certainly not for anyone who has no experience working with them. If not used properly they can do more harm to the metal you are working on (not to mention yourself) and make the situation even worse.

[owenk]

I used navel jelly on the floor of my 620 Pick-up and it worked great. Just follow the directions. Got it at home depot.