Vinegar rust removal.

[Grimly]

Ditto on the phosphoric acid. I use a 20% solution painted on to raw rusted steel, leave overnight, wash off, let dry, then prime and paint. I did my trailer chassis that way and rust has not been a re-occurring problem at all. It leaves iron phosphate behind.
Now this thread has mentioned it, I am minded to use it in my other GS tank, which has been sitting for 15 years or so and is likely needing something like this in it.

Prep & Etch is still around. You can get a gallon at Home Depot for about $15.

Guess what, it's acid, so don't drink it or soak your hands in it.

Unlike muriatic acid, however, it won't melt your face off, eat through metal beyond the rust, spew fumes that choke you to death, etc.

Unlike vinegar, it will de-rust your tank in an afternoon, not 2-3 days, and will not flash rust in 5 seconds after draining the tank.

Dump the whole jug into your sealed tank, slosh around every 20 minutes. Do this for about 3-4 hours (while you're working on other stuff in the garage). Rust will be gone, and a nice layer of phosphorus (or something) will coat the inside giving you plenty of time to rinse and seal, or just rinse and fill with gas.

Even better, when you drain the acid out of the tank, strain it through some cheesecloth and put it back in the jug. You can use it again later if necessary.

[themess]

Use this to remove the rust in the tank. Way better than vinegar, because it allows zero flash rust if you follow it with some WD-40, liner, etc. without the "race with the Devil" that vinegar requires.

I checked out their web site

http://www.wmbarr.com/kleanstrip/kleanstrip_about.aspx

Klean Strip sells chemicals for professional use. Amateurs will usually get away with using such chemicals, but not always. Phosphoric Prep and Etch is probably one of their safer chemicals. Phosphoric acid treatment is one of the safer methods to remove rust. Industrially, and probably in Prep and Etch, some chemicals are added to "passivate" the surface. Passivation is treatment that protects the surface from rusting for a few days, which is better than the few minutes needed for rust to start on a perfectly clean surface.

Still, concentrated phosphoric acid can be quite dangerous. I would not keep it anywhere that children can even pry into.

The Klean Strip web site has other chemicals that could be very useful in surface preparation, but they all seem to be designed for professional use. In practical terms, professional use means:

> Supervision by a chemist or engineer who understands the chemicals and their hazards, who can control how they are used, who can use them, and under what circumstances, and how the chemicals are disposed of.

> Trained people

> Use only with appropriate protective gear, used properly.

Note that many of Klean Strip's products are labelled "Discontinued". I'm guessing that too many customers were not using those products safely, exposing Klean Strip to liabilities that they decided did not justify the profits.

Vinegar is good stuff, and when you chase it with a bit of alcohol, it does not leave a flash rust coating. That said, while the vast majority of the tank is completely rust free (probably in excess of 99%), there is still a small amount in the lap seams where the tank is welded. Has anyone been able to remove this or am I over thinking this a bit. I am afraid to leave these deposits since I believe they may allow corrosion to continue beneath them. What say the experts on tank cleaning and restoration. Thanks, Ray

Use this to remove the rust in the tank. Way better than vinegar, because it allows zero flash rust if you follow it with some WD-40, liner, etc. without the "race with the Devil" that vinegar requires.

[Ghostgs1]

Tom, Thanks for your opinion, I agree with you on the fate of our bikes ultimately. Just a bit worried about the crud in the seam as I am thinking of using a sealant, probably Caswell and I really would like to have all of it out of there. I guess if it does rust further it won't leak with the coating and due to the coating it may not be able to rust further. Ray

[themess]

.... there is still a small amount in the lap seams where the tank is welded. Has anyone been able to remove this or am I over thinking this a bit. I am afraid to leave these deposits since I believe they may allow corrosion to continue beneath them. What say the experts on tank cleaning and restoration. Thanks, Ray

I'm not expert and I've never done it. I do know some chemistry. Without oxygen, iron can't rust. Gas tanks in service don't rust because they are filled with gas and gasoline vapor, both of which exclude air and the oxygen in it.

I'm guessing that the gas tank cleaning and sealant kits miss rust in seams. Covering the seam with sealant should exclude air, or reduce the rate at which air gets to the metal to such a low rate that it doesn't matter.

Rustoleum paints used to have instructions about completely removing all rust, then priming. They now say to clean the surface, that the paint is self-priming, and to paint over rust remnants. This could be hype, or it could be that the paint film is designed to penetrate the rust and prevent oxygen from getting to it. Again, my speculation.

In your shoes, I would be tempted to use the gas tank as it is. If you can photograph it, do so. Once or twice per year, drain the tank, take it off, and examine it to see if the amount of rust is increasing. If it is, seal the tank. If not, continue using it.

Our motorcycles are already 30+ years old. They will fade as, just as we will. Except for the museum pieces, our GSes will go into the scrap heaps soon after we are buried. Today a GS is still a perfectly viable daily use motorcycle. Who would have thought so in 1977? But in another 30 years? The only parts we'll be able to find that don't come from cannibalizing old bikes with be standard fasteners. Eventually, rust in the tank won't matter.

[Ghostgs1]

Vinegar is good stuff, and when you chase it with a bit of alcohol, it does not leave a flash rust coating. That said, while the vast majority of the tank is completely rust free (probably in excess of 99%), there is still a small amount in the lap seams where the tank is welded. Has anyone been able to remove this or am I over thinking this a bit. I am afraid to leave these deposits since I believe they may allow corrosion to continue beneath them. What say the experts on tank cleaning and restoration. Thanks, Ray

[chuck hahn]

Got 4 gallons of the 8% "cleaning" strength ready to go in to a 83 CM 250C tank. Matt got it yesterday for 200 bucks. Clean as can be. Two little dings in the tank, but every factory sticker still on it..even the ones on the tank by the filler neck.

Had brown liquid varnished gas in the tank and that's what really saved the bottom from rotting away. Needs derusted and a liner but as sweet as it is for 200 bills.....slam dunk.

Carb is in the dip right now. Will be a runner again very soon. Last registration sticker on the plate was from 03.

Gonna be for his girlfriend and his daughter to learn on.

[tkent02]

Yes, we're still here, overlooking the mud flats along the mighty St. Vrain.

Glad to hear it.

[Ghostgs1]

I don't know, the whole thing might explode. I'm not a chemist.


But I was thinking of trying it. I'd fill it with gasoline as soon as possible and keep it full, wouldn't even coat it. But we don't have condensation issues in this dry climate. By the way, did your house float away or are you OK?

I decided to give it another vinegar bath, as it was looking pretty rusty already. I think I'll just do a good flush with alcohol as quickly as I can after the vinegar comes out. The tank doesn't have any leaks, but it sat for quite a while with nasty stale gas in it. The surface was pretty rough after the rust came out. Seems like coating might be a good choice.
Yes, we're still here, overlooking the mud flats along the mighty St. Vrain. They still haven't allowed traffic to cross the bridge on 119, but it will probably happen soon. I kind of wish it had washed away, the neighborhood is much quieter and calmer without the racetrack. Ray

well after cleaning the carbs with vinegar, I got them on, synched and went for a 100km trip today and they performed flawlessly. I'd say they are clean as a whistle.

Gas mileage was good too so I'd say its proven as an internal cleaner.

A cheap alternative to the automotive carb dip.

[tkent02]

I don't know, the whole thing might explode. I'm not a chemist.


But I was thinking of trying it. I'd fill it with gasoline as soon as possible and keep it full, wouldn't even coat it. But we don't have condensation issues in this dry climate. By the way, did your house float away or are you OK?

[Ghostgs1]

Thanks Tom, That might work, then chase the anti freeze with alcohol. I think I'll give that a try, can't hurt and not expensive. Ray

[tkent02]

Got some old used anti freeze?

I was thinking put a little vinegar in, slosh it around until the tank is clean, then fill it with antifreeze. Not sure if it would work or not, but there are rust preventatives in antifreeze.

I have one tank I filled with kerosene to prevent rusting, haven't looked inside lately though.

[Ghostgs1]

Ok, after using the electrolysis method for cleaning my tank, I wasn't very happy with the results. So, I decided to use the vinegar method. I can say it is an amazing method, soaked for three days and then emptied it out. Unbelievable amount of rust products came out with it, probably near 2 cups all told, so that is great. The interior looked almost new while still wet with vinegar, but as the vinegar evaporated the surface flash rusted as you would expect as the air hits the damp metal. This is just a film, but I am left wondering if an alcohol rinse will be enough prior to coating with either Carswell or POR-15. What say you that have gone down this road before? Thanks, Ray