Tank Rust removel with nice paint/how to

Hello . I just picked up a 74 Z900 gas tank that has a super factory Green/Yellow paint job. The tank does not leak however there is alot of surface rust inside. What is the best way to remove rust without damage to paint job. Thanks Gregz

Buy phosphoric acid at the hardware store. It comes diluted and is known as tile & grout cleaner, or Naval Jelly. Some tile cleaner is now acid free, so check the ingredients, I don't know if they will remove rust. The phosphoric acid reacts with bare metal leaving behind a thin coating that resists rust, or so they say. The acid is not bad to the paint, but be careful. Rinse and wipe off all spills.

Just remove the gas lid and petcock, Duct tape the openings, add a small length of kid's swingset chain, or a handful or nuts and bolts. Wear some gloves and eye protection. Add your acid, seal the top, and swish around for a while until the acid and chain clean off the rust. Fish out the chain, rinse out the acid with water, and then dry the inside with a hair dryer. The tank will flash rust but it's not serious. Replace your petcock and cap. If you plan on storing the tank then add some light oil, swish around to coat the tank and keep from rusting. Otherwise mount it up and fill with gas.

Post edited by: OKC_Kent, at: 2007/10/20 10:00

Hi Greg,

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GregZ

Fill the tank half full with rinsed and dried chicken/turkey grit.
Wrap tank with blankets.
Strap tank to rear tractor tire. (jack rear of tractor of ground)
Spin very slowly for about 1hr. more if real rusty.

It's worked for me.

FastKaw1 wrote:

Fill the tank half full with rinsed and dried chicken/turkey grit.
Wrap tank with blankets.
Strap tank to rear tractor tire. (jack rear of tractor of ground)
Spin very slowly for about 1hr. more if real rusty...

Although I did mine the way OKC_Kent described, I think FastKaw1 should win some sort or redneck ingenuity award for this... :lol:

If it is only mild surface rust. you can use CLR which you can buy in the cleaning section of any good grocery store or Walgreans farmacy.

del

CLR is a Hydrochloric and Acetic acid product which has other aditives to prevent re-oxidation. And do you mean Muriatic acid and not Phosphoric acid. Phosphoric acid is used to clean Aluminum. I have 6 galons of it to clean Airconditioning coils. Muriatic acid is sold in Hardware stores to clean Driveways and is used in the steel industrie and molding industrie to remove rust from molds, we use it at work after we EDM cut a chunk of steel. If you want to use the muriatic acid I recommend deluting it about 4:1 with destilled water. Muriatic acid is a derivitive of Hydrochloric acid in a dilute form.

otakar wrote:

...And do you mean Muriatic acid and not Phosphoric acid. Phosphoric acid is used to clean Aluminum...

I used phosphoric acid. Actually, I used Naval Jelly. But, the gel nature of it meant it didn't spread around as well as I would have liked, no matter how much I shook. So I got the other stuff mentioned above, which is a more liquid form, and I'll use that next time on another tank... this winter..

del

I have repaired several rusty tanks in the past using epoxy. I got advice from the tech support people from West Systems epoxy.
You can clean the tank,if you want,with phosphoric acid, although it is not necessary. The epoxy will encapsulate the rust, keeping it bound up so that it won't contaminate your fuel. The added benefit is that it will cut of the oxygen from the metal, stopping the rust from progressing. It will even seal small pinholes.
Take all fittings off of the tank. Duct tape the openings. Be prepared to drill and re tap any threaded openings. Mix up the amount of epoxy that you think you will need and pour it into the filler opening. Tape up the filler opening. Rotate the tank in all directions to coat the inside of the tank. You can stop rotating after about 20 minutes or when the epoxy starts cooking. The container you mixed the epoxy in will let you know when the epoxy in the tank is setting up.
I have two tanks that have been done this way for over ten years and they look like they were done yesterday. One even had small pinholes.
I recently did a large tank for a jeep pickup. I thinned the epoxy with acetone to make it flow easier. That shouldn't be necessary for a tank no bigger than a mororcycle.

What's the song, "Rust never Sleeps" by Neil Young?

I don't know how rust works with oxygen, will it really stop doing what it does if you cover it with epoxy?
I personally think it will keep eating away and will bubble up the paint at some time in the future. Your gas may be free of rust, but what is happening behind the epoxy? This may be the way to go if your tank has pinholes.

It's too cheap and easy to ELIMINATE rust with an acid bath.