What Is the Acid That Converts Rust?

[eric77super]

I remember not too long somebody posted that a certain mild acid wash turns rust permanently gone, anybody remember what type of acid it was? I used phosphoric acid and it immediately generated rust so I don't that was it but I could've sworn somebody posted about a certain acid that makes "no more rust" and by the way how permanent is this method?

Gonna treat the fuel filler neck on the 77 SB

Thanks
Eric

[Bugfuel]

http://www.jamestowndistributors.com/us ... word=ospho

we use this stuff at work

[fusername]

buying a new car stops rust? I shoulda known!

muriatic acid may be what you are looking for. It doesn't so much kill rust as disolve it whilst not touching good metal, then when you prime over it there is no "starter rust" for the cancer to be reborn from. make sure you rinse it all well before painting though, leaving the acid may or may not promote rust in the future.

[Bugfuel]

LOL my link copy didn't take so I accidentally pasted an older link that was still in the memory... and it happened to be one of the worst kind... The VW of America 2010 lineup
All fixed now.

[Dougy Dee]

Phosphoric acid. I believe it's the main ingredient in bugfuel's recommendation.

[raygreenwood]

Yes...if you are trying to convert the rust to iron phosphate....which by itself will never rust again.....use any of numerous products that are primarily phosphoric acid. Ospho is one brand.
The issues are this: The iron phosphate coating will never rust again, but it is thin and has a very porus surface. It can and will absorb moisture and over time...start rusting....but very slowly. It makes THE BEST primer...hands down...better than zinc-Di-chromate (that green aircraft primer). You should paint it after you convert it. In the filler neck use an epoxy like Por-15.

The other issue is that phosphoric acid will only convert what it can reach. Typicaly...rust penetration is about .001"-.002". So if you have crusty rust, the best thing to do is soak it in 60% to 40% muriatic acid and water...to totally dissolve all rust. Then...rinse well...and let it sit damp for 24 hours. Very quickly it will develop very thin and very even surface rust....may .0005" thick. Then hit it with ospho.....and the converted surface will be very nice and even. Then paint it. Ray

[Bugfuel]

What Ray said!

[Dougy Dee]

I came across a product called Rustbeeter at a local car show. Beet juice... There's a web site. I'm sure a google search would find it.

[raygreenwood]

I came across a product called Rustbeeter at a local car show. Beet juice... There's a web site. I'm sure a google search would find it.

Very intriguing! Ray

[hugging corners]

Its called oxalic acid
its a white powder you dissolve it in warm water, dip in, after 24h youll get shiny piece. This acid will penetrate metal, but leave everything out (even plastic stickers).

it was used to bleach wood

great stuff. i have used many other acids for rust, this one the best and the cleanest so far



ive got pics, not sure if i can give other forum web address, but that's info only

scroll half the page you will see all the chrome before and after being dipped

http://www.thesamba.com/vw/forum/viewto ... sc&start=0

[doc]

Nice build! Welcome to STF! Thanks for the tip.

doc

[greggholmes]

I have used Oxisolv rust remover and i loved it. parts came out looking sandblasted. they may have changed the name.

http://www.eastwood.com/ew-rust-dissolver-gallon.html

[Devastator]

I've used Picoclean X-rust remover, and it works very well. Hard to believe you mix it with water.
http://www.picochemical.com/Picoclean%2 ... ochure.pdf