The Stovebolt Site Forums The Shop Area General Truck Talk Gas tank rust ! phosphoric acid??

I need to clean out my tank, I did a search here but didn't find anything? anyway someone told me to use phosphoric acid? what is your experiance with the best way to clean out the rust? I don't really want to use a sealer, as everyone says they eventually fail and cause more problems. my tank is in nice condition and is clean, except for the last quarter of the tank. Rust/water/dead gas at the bottom from sitting.

there's no point in cleaning it if you're not going to use a sealer, it'll continue to shed particles until holes show up

many rad shops will boil them out in their cleaning tank and do a proper job of sealing them, won't fail if done right

Bill

rustmaster: I sealed the tank on my 37 about 8 years ago with the Por15 kit and it has held up very well. Do a search and read all about it. Some folks said it would crack but if you do your research on it and you'll find out why it won't crack and holds up very well.
As for it "eventualy failing"....well, most anything will fail over a long enough period of time....especially if it pertains to mechanical stuff. It will fail...eventually. I vote seal it.

i used por 15 on a bike tank spent hours cleaning and drying it looked grate put it on the self got it down a year later the stuff had all come loose what a mess what i should have done was put gas in it and keep gas in it thats the trick it keeps the sealer working let your tank set empty with sealer in it and you will have a mess iv decided your money ahead just to buy a new tank no more sealing for me! but thats just me

I agree with red58 on this. You should seal it after you clean it. Eastwood Comany sells a good kit if you are looking to do it yourself. The Por15 kit also comes with high recommendations. Probably can't go wrong with either one.

If you are just trying to clean your tank out, then go down to your local home improvement store and buy some acetone. Dump out the old fuel. Then pour in some acetone and drop some nuts/washers/etc. in and shake it. (Note: just remember how many nuts/washers/etc. you put in there so that you can make sure you get them all out). You might have to flush and repeat a couple of times.

Hope this helps,

All of the "kits" I've seen for cleaning/coating tanks use phosphoric acid for the cleaning/derusting. It's slow working (usually overnight soak) but does OK. I use Muriatic acid because it cheap & fast. It is much more aggressive than Phosphoric so if you use it be sure to kill the acid with a healthy dose of soda water (baking soda & water mix) before you dump it out. After using any acid cleaner you MUST coat the tank or it will not only continue to rust but will rust faster. The idea of a full gas tank stopping the rust is an old wife's tale. None of the radiator shops around here will touch gas tanks. You may find one where you are that will but don't count on it. I use Red Kote & have never had one fail yet. I've used Kreem in the past but it's a "softer" coating than Red Kote. I've not used Por15 but have heard good about it. Whatever you use be sure to follow the manufacture's instructions. Those who's coatings failed didn't & paid for it.

I just went through this last year. Heres the link to it.

Sealers

Muriatic Acid

I have been doing some research on this and came across this posting.
http://groups.google.ca/group/rec.crafts.metalworking/tree/browse_frm/month/1993-09?_done=%2Fgroup%2Frec.crafts.metalworking%2Fbrowse_frm%2Fmonth%2F1993-09%3Ffwc%3D1%26&fwc=1

K's radiator repair, plainfield nj. will boil and clean and seal. offered to do my 46 pu tank for 160. would definately done it except i dont have a bottom to my tank as i just pulled it and found it gone. they did my rad/chipmonk condo for 150 and it is now cleaned sealed and painted w/ 95% flow. great people.

have heard bearings/bbs are better than nuts and bolts. kerosene is a great cleaner. a few straps and a cement mixer and you have a great cleaning system.

For the cost of boiling and sealing a tank here in the Houston area it is almost cheaper to buy a new one.

most paints these days are "systems", especially specialized paints like tank sealer. The phosphate coating left behind by phosphoric acid that they tell you to use with POR 15 tank sealer is recommended for a reason. Regular POR 15 sticks best to a light rust haze, much better than to bare metal, the reason is the chemical bond of light rust to base metal. Flaky rust is as different thing. With this said, POR 15 tank sealer sticks best to the phosphate coating left behind by Phosphoric acid, not hydrochloric or sulfuric. Acid etch used for car bodies in body shops is phosphoric acid. There may also be other paint systems that use other acids. Follow the manufacturers recommendations to the letter and you will get good results. If tank sealer fails, it is because it did not stick to substrate (coating on the base metal). THe acid cannot produce this layer on top of the metal if it cannot penetrate the varnish and other stuff on the surface. Acetone may be great to dissovle varnish, but it will not convert rust, OR convert a clean metal surface to a phosphorus substrate that the POR 15 system is designed to stick to. Buy a new tank for 200$, it is the best option, for one you can't find a new made example, seal it because you have no other option. Sealing a tank will cost you 60 bucks or so. I have a 64 gmc with a sealed tank of 2 years and still going strong. The inside was shiny but it had rust holes from the exterior tank straps. When I cleaned it with the POR system, all kinds of brown crap came out every flush, and that was with what looked to be a clean tank to start with.
Hope this helps