Rust removing agents

[Dom]

What's a good way to actually remove as much rust as possible in a tight spot? It's not Z related but I'm trying to take a fuel line apart but fittings are rusted, I figured this would be a good place to ask After wrestling with it for an hour I'm out of options. Is there a solvent I can spray on it? I've read that anything with oxalic acid would do but I don't know any products that use it. Any suggestions would be great.

[TheNeedForZ]

Are your parts bonded together because of rust? Rust remover are used only for surface prep. If your parts are bonded together in some thick rust, then rust removers won't help at all.

 

Any stronger acid will remove rust : strong vinegar, hydrochloric acid, nitric acid, etc. Most rust removal products out there use different combination of SAFER acids plus gelling agent(to make it stick well to surfaces), and color.

 

Most rust remover contains phosphoric acid or oxalic acid. They are actually not strong rust removers but they are universally used because they form a protection when they come in contact with the base metal. This protection allows rust to be dissolved while stopping acid from eating away metal. So any brand of rust remover is fine, they all eat rust and protect the base metal. It all depends on how thick you want it to be; Some are thicker for sticking to large vertical areas, others are not so thick.

 

Clean the surface so it's free of oil/grease/fuel before you apply. Your rust remover can't work if it is not in contact with the rust. If you have a

thin-walled part that is heavily rusted, the part might become too thin or full of rust holes when all the rust is dissolved.

[Dom]

Thanks for the tip. I'll try vinegar. I wouldn't say they're bonded together but thread on the male fitting are rusted. I suspect that female end might be too since I can't crack it open and I'm no wimp. Any fluid that can help dissolve the rust at the edge of the female fitting and maybe penetrate between threads should help tremendously.

[auxilary]

small wirewheel on a drill? file?

[Dom]

Didn't find one at auto parts store. Maybe Home Depot will have it. I'm worried though that threads inside the fitting might be seized together from rust, etc. I guess I'll find out tonight after work.

[Oleh]

WD-40 on bolts... sandpaper/grinder on rust

[wheelman]

I noticed you said it was a fuel line, if it has been drained and is dry use a little heat from a torch. Blow out the line real good with an air compressor first to make sure the vapors are gone.

 

Wheelman

[TheNeedForZ]

I did bought mine from home depot.

 

If the rust is INSIDE the threads, then forget about it, you need something other than rust dissolver. Can you sacrifice one of the male/female fittings? like cutting a relief groove into the nut or something?

[Brad-ManQ45]

For rusted bolts/nuts, nothing I've tried works better than Kroil.

 

Phosphric acid is not a rust remover, it is a rust converter - used to get the microscopic rust in pits after visible rust has been sanded/ground away.

 

Several products on the market contain phosphoric acid - OSPHO can be found at NAPA stores and paint stores, PickleX (formerly Rust Mort) goes a step further than OSPHO does - if the car is in a shop, you sand/get rid of all surface rust and treat the surface, it can be left alone until time to spray. With OSPHO, you basically want to treat it, let it dry, then prime.

 

Navel Jelly is a common rust REMOVER, but you must make sure that you rinse thoroughly or you have problems painting over it.

 

Even if using a rust remover, use a phosphoric acid treatment on the metal before priming.

[TheNeedForZ]

Brad, I had to disagree with some minor details, and forgive me to get the chemistry straight here.

 

Naval jelly is basically phosphoric acid plus gelling agent. Phosphoric acid is a rust remover just as naval jelly is a phosphoric acid treatment.

 

Rust converter are tannic acid plus other acids, IIRC, it uses some sort of chelating action to convert the rust.