Tank coating - phosphoric acid - cola?

[dontlikeoc]

I am cleaning rust off from inside the tank this weekend. I want to use phosphoric acid to coat inside once it is clean. Although I looked for it everywhere, Home Depot, Lowes, Kragen, Autozone, etc. , I had no luck. Interestingly, I noticed that Shasta Cola has phosohoric acid written as #4 ingredient.

Did anybody use Cola to coat inside the tank? How was the result?

[tarzan]

I used lemon lime soda on a tank with some rust in it and it did pretty well.
Do a search on here for rust removal,There are some good threads on here.
Electrolysis is one method that guy's here have had good success with.
Rick

[dontlikeoc]

Thanks for your reply.

I am actually doing an electrolysis right now. (Keeping the tank suspended in a bucket is a challenge but I at least see the rust on the sacrificial annode.) I am looking for phosphoric acid for rust prevention after the tank is rust free.

[tarzan]

Will phosphoric acid keep it from rusting?If you just want to dry it out good,you can use acetone too I would think.

[Ivan]

Naval jelly is just thickened phosphoric acid. Also many of the wheel cleaners you buy at the auto parts store have a very high amount of phosphoric acid. If you don't want to mess with naval jelly, got to the store and crack a bottle open and have a sniff. Phosphoric acid has a very unique odor to it, and you can sniff out a bottle of wheel cleaner that has the same thing.

Also, oxalic acid is supposed to be the best rust remover. Its sold as "wood bleach".

Lastly, I have been told that CLR does a heck of a job on rust in a tank.

[Athedra]

By the sound of all of this, I did mine the wrong way, but seemed to have worked for me.

First stripped everything and threw a bottle of pool acid in there. Stood there overnight, and took the acid out the next morning. Wont believe what comes out of your tank the next morning. Rinsed it with fuel, and let it dry (evaporate). Then dumped 500ml of rust remover paint in there. Shook it the tank all about and then threw out the rest of it, leaving it with a thin layer of Rust remover paint in it. Stuck a air hose in there for about 30 minutes and then dumped Roof rubber in there. It's a liquid rubber that dries into something similar to silicone when dry. Like I said they use it on zinc roof tops on the screws to seal it. The tank stood over night with a air hose on it, and then remembered the next day that I should have removed the petcocks. So removed the petcocks, scraped the filters clean and sealed of the ends that got damaged while removing the petcocks. Same method just with a brush. Sealed in my petcocks, and have not had any rust coming through the tank again. Also sealed the leak I had on RH joint from the inside.

So in short I have a zero rust, completely sealed, internal rubberized fuel tank.

[dontlikeoc]

Thanks for suggestions.

About Naval Jelly, there is only one kind of NJ product I could find at local stores. And the container says there is a separate product that is for rust prevention. I could never find it.

I will check out the wheel cleaner too.

Nobody seemed to have used Shasta Cola for phosphoric acid...

[Xcess11]

Try OSPHO

When I was in the service we used to use this stuff called OSPHO.It's applied on metal as rust remover and surface treatment. I've never used it on the inside of a gas tank but I don't know why it couldn't be used there.

This is quote from the OSPHO company website. (and no, I don't work for them)

"RUSTED METALS - OSPHO is a rust-inhibiting coating - NOT A PAINT You do not have to remove tight rust. Merely remove loose paint and rust scale, dirt, oil, grease and other accumulations with a wire brush - apply a coat of OSPHO as it comes in the container - let dry overnight, then apply whatever paint system you desire. When applied to rusted surfaces, OSPHO causes iron oxide (rust) to chemically change to iron phosphate - an inert, hard substance that turns the metal black."

[Ivan]

So in short I have a zero rust, completely sealed, internal rubberized fuel tank.

That sounds like the self sealing tanks on the old WWII fighters.

I bet it doesn't leak!

[Larrym]

Rust never sleeps...

I have used the product "OSPHO", available at hardware stores, to treat many rusted fuel tanks and I'm happy with the results. The rust is converted to a black material which in most cases doesn't need painting or further attention.

The rust expands the metal to ten times their original volume but with little of the original strength. So the treatment can sometimes coat the surface rust but allow for a big and deep section of rust to flake off. I would suggest using some technique to knock off as much of the rust inside the tank as possible before using the OSPHO. My personal favorite is to put a 12 Oz. container of steel nuts inside the take and shake vigorously.

[Athedra]

That sounds like the self sealing tanks on the old WWII fighters.

I bet it doesn't leak!

HAHAHAHahahaaaaa......Kinda does.

The rustists (Rust remover) I used left a black painted layer, and was worried that it will come off as soon as the fuel hits it. That is why I rubberrized the whole thing.

[dontlikeoc]

After 2 1/2 days, it looks like the tank in electolysis bucket stopped bubbling. Rust is thick on the wire hanger.

Although the rubberizing is also tempting...I think I will go to a mom and pop type hardware store to see if I can find OSPHO. (POR 15, I hear also is good is too hard to find. Naval Jelly specifically saying that they have a seprate rust prevention product is a kind of unnnerving.)

[dontlikeoc]

Now, the electrolysis is done. I am very happy with the rust removal result. As for the rust preventer, I used both Naval Jelly and Coke. I think Coke works better for that the coke bubbles helped get the sandy rust pieces to slosh out of the tank better.

However, I submerged the entire tank and the 30 year old paint peeled off. Now, I have to deal with paint stripper and priming...

[fredintoon]

Molasses

Now, the electrolysis is done. I am very happy with the rust removal result - - -

Hi dont,
FYI and for future consideration, here's what antique machinery restorers use on really old sheet steel parts that are turning into iron lace. Mix up a bucketful of blackstrap molasses & water, between 1/10 and 1/20, dump the part in and leave it for a month. It works! I de-rusted a gas tank like that. Be warned that the mix can go bad over time and while that won't harm the part it's best to dispose of the mixture by pouring it down a street drain late at night.

[dontlikeoc]

Hi dont,
it's best to dispose of the mixture by pouring it down a street drain late at night.

LOL...I cant agree more. I live in an apartment any work on bike is a challenge...