POR-15 and a gas tank

[dardoonk]

As far as rust removal, Evapo-Rust is safe for paint and hands, and doesn't create the noxious fumes that acid treatments do.

It's also far more effective than any acid treatment, and won't damage the intact metal under the rust.

You can get Evapo-Rust at any auto parts store -- it's in silver-ish gray quart or gallon jugs near the paint and such.

I know of at least one badly corroded (but with flawless paint) motorcycle tank treated with Evapo-Rust with excellent results.

Have you tried this? How were your results? I've used it on a number of nuts, bolts, etc, and had excellent results. Even after sitting in the open air, no rust has returned. I was so happy I figured it would easily take care of light silty rust in my tank, so I bought five quarts of if and kept rotating my tank for hours. When I drained and flushed, it was perfect inside. I was real happy with the results, but after about 5 weeks (buying good fuel & keeping it topped off), the rust seemed to re-appear?? I was shocked and now trying to figure out why the only failure I have had using Evapo-Rust is from tank job. I still have about 1 gallon of it in a pail and it still works well on small parts.
Hope you had better luck than I did on the tank... It's too easy to use to screw up, so I might have to try the POR15 deal.

 

[LarryA_Texas]

I did the electrolysis method on my tank after doing the cha-cha with it using a large handfull of bb's...Well, getting all of the damn bb's out was rather difficult too. ...

I used a magnet. Auto parts stores have little magnets on a telescoping handle for about $5. Well worth it to get metal objects out of your gas tank.

That's one reason why I'd use nuts and bolts instead of pea gravel. It's a lot easier to get all the metal out with a magnet. Just use smaller nuts and bolts. Big ones can put small dents in the tank.

When you're done with the tank, I think you'll use that magnet for a lot more things. Like pulling that little screw out that just wedged itself in a tight little corner of your frame.

 

[Nessism]

Nuts and bolts doesn't have the contact area of pea gravel since it's smaller, I've tried both. The difference is dramatic. Actually, aqurarium rocks works even better than pea gravel since the texture is rougher.

Regarding the Evapo-Rust removing the rust, it does work but the metal is left raw so to speak and rust will return if the metal is not sealed. Not sure why it would rust more than the original tank, but it seems to be the case for some reason.

 

[Old Colt]

Phosphoric acid wash or any phosphate coating will do a good job of preventing rust after a cleanout of the tank. Metalprep used in autobody work will do just that.
Problem is todays fuels are oxygenated and will induce rust. Keeping the tank full of fuel just puts more moisture and oxygen in the tank. It makes the rust problem worse than draining the tank.
Times have changed and to keep our old toys alive we need to change also. Protective coatings are becoming a must to keep out the rust.