Plastic bucket, water, sodium bicarbonate, battery charger and a rusty part!

[berettafan]

Before and after. First time i've tried this and all i can say is i wish i had done so long ago. Unreal how this works!

[RRico]

Damn....nice!
How long did you have the part in the solution?
Can you do this to all metals or just certain types?

[Shaun @ Tru6]

Excellent. this should be in technical. What is the + lead of the charger connected to? ratio of water to NaHCO3?

[Scuba Steve]

Yeah it's a great trick, isn't it? I think it's called electrolytic rust conversion. I've been doing it for over 5 years with great results. It works only on areas with a line of sight to the electrode, and loosens paint as well as rust a lot of the time.

[masraum]

OK, cool, we need more details. Technical instructions.

[masraum]

OK, I took "electrolytic rust conversion" to google.

http://myweb.tiscali.co.uk/andyspatch/rust.htm

http://www.instructables.com/id/Electrolytic-Rust-Removal-aka-Magic/

[Scuba Steve]

When I do it, I add a tablespoon or two to a gallon of water. Remember to keep the clamps for the battery charger out of the water or it'll mess up the metal. You'll also need to paint whatever you remove the rust from pretty quickly - the steel is ready to oxidize right away.

This has been by far the most effective way I've come across to clean rust out of deep pits. As long as you prime whatever you treat quickly you'll have great success in keeping your stuff from re-rusting.

[berettafan]

http://thisoldshed.tripod.com/electrolysis.htm


Lots of sites out there detail this but here's one I found.

Parts sat for about 3hrs. They are exhaust clamps and were likely so bad because a) they were near the ground and b) they were very hot every time the bike was used.

Positive clamp was attached to a piece of scrap steel which now looks like it has been submerged in salt water for a few years (looked great before!). I STRONGLY SUGGEST READING UP ON THIS before attempting it. You are working with electricity in close proximity to water AND creating hydrogen gas.

[berettafan]

That's probably $60 of exhaust clamps (effing vintage beemer parts are more dear than Porsche parts!) i don't have to buy now!!! The pits are still there and if you have rust UNDER the finish you can expect the finish to go away as well. But at that point the part is kaput anyways right?

80% of the exhaust pipe looks even worse than those clamps and i'm going to try that next . Already have a new replacement but it never hurts to have a serviceable spare!

[berettafan]

All-

Forgot to mention there is the issue of hydrogen embrittlement. In other words don't use this process for stressed suspension parts, etc. Read up on this and supposedly you can bake the part at xxx deg. for xxhrs and undo this problem.

[targa911S]

Annealing is an art. You must now a lot about metals before baking and cooling. Do your homework.

[Shaun @ Tru6]

I'm seriously going to consider getting a kiddie pool for my various hoods, decklids, etc. that all have minor pitting that would require soda or glass blasting to get clean. Could be the perfect, ahem, solution.

[widebody911]

I've developed a two-step process for prepping engine tin for paint.

The first step is to soak the parts for a couple days in my heated parts washer, which will loosen the existing paint and I can remove what's left with a scotch brite pad.

The second step is to soak in a big plastic storage bin filled with water and CLR, 1 gallon of CLR to ~15 gallons of water. The CLR will dissolve the rust, but not harm the steel. I did a test this weekend, and it seems that it ignores aluminum as well: I soaked a VW bug/bus intake manifold for two days, which cleaned off all the rust, but didn't do anything to the aluminum heat jacket.

My process takes a few days, but I'm not in any particular hurry.