Acid (type) For Rust Removal

Can Anyone provide me with what type of Acid you can use to loosen or help fight rust. I have a Gas tank that I would like to wash out real good before trying to coat inside. Any Help Appreciated.

I use two kinds; but, first off it's necessary to warn about the hazards of strong acids. A person only has one pair of eyes, so I wouldn't even think of working with acid without using a full face shield, rubber gloves, and clothing that covers all exposed skin.

That said, I use both hydrochloric and phosphoric acid. You can get the hydrochloric in hardware stores and plumbing shops. It is nasty stuff. Use it outdoors and keep it down wind from you. The chlorine or hydrogen chloride vapors it gives off can be really hard on your lungs.

The HCl is much more aggressive than phosphoric. When I have stubborn rust to remove, I'll use the HCl, first, and finish up with phosphoric.

After using acid you should rinse off the acid and then passivate the freshly etched surface, otherwise you're apt to get some serious re-rusting. To passivate, use Ospho, Jasco Metal Prep, or a similar phosphoric acid/metal salts formulation. Any good paint department should have one or the other. By-the-way, your phosphoric acid won't do a good job of passivating. I've tried it and it doesn't work. In about a day I had worse rust than what I started with.

Now that your have your partially-used jug of hydrochloric acid, let me warn you about storing it. Even if it is in a sealed container, if you store it indoors, every piece of iron within ten feet is apt to rust. Severely. I keep my jug of HCl outdoors, sealed in a plastic five gallon bucket.




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Dear Brian you can use Muriatic acid to clean and etch a fuel tank but keep in mind this is strong stuff keep away from skin and anything you dont wont ethced. When you put the acid in the tank I would try to fill it all the way up but do not seal the openings allow it to vent. You need to do this out doors on a good sunny day as this helps with the acid fumes and also will help evaporate the water after you wash out the acid.You will need to instantly after rinsing well with water fill the tank about half full of MEK avaliable in most paint stores this removes the remaining water but dont let tank completley dry as rust will instantly form have tank sealer ready and immedeatley pour in and slosh around you may want to seal the openings at this point

If you want to try an acid free rust remover,I recommend EVAPO-RUST. E-mail back and I will respond with the important info about this great new product. It is perfect for cleaning gas tanks.

[Robt.]

Funnily enough the Canadian distributor's website tells more about it than the manufacturer's site!

http://www.evapo-rust.ca/index.php?p...ut&content=how

Sounds great. Can't wait to try it in some water jackets.

[Franz©]

Well, just to piss on the parade of the wonderful folks hawking rust removal miracles, let me just say this.

EvapORust is a chelation process, Yea, whoopie yahoo. So is molasses! That's right, EvapORust is exactly the same process as submerging your rusty object in molasses to remove the rust. Now, if you don't live in an area where cows are common, or, if you want to do chelation without smelling molasses, and yearning for good molasses cookies, I can also provide the name of the manufacturer who mass markets a chelation product, and will private label it for you.


Acid processes, basicly, there are 3 acid processes, and they are the basis for 90% of the overpriced crap being sold for rust removal/coverup.
Muriatic will disolve rust, and also steel. Muriatic is very fast, and stinks worse than your brotherinlaw's feet in a hunting cabin. If you aren't fully conversant with Muriatic, and don't have proper safety equipment, you shouldn't be using it!!

Tannic acid also works, and if you want to experiment, grab a handfull of teabags and go play.

The best acid process is Phosphoric acid! $ to 8% by volume in water, probably about the same concentration as a can of Coke, and it will convert the rust from iron oxide to iron phosphate. You don't even need rubber gloves to use it, and you can dump the solution on your vegitable garden when you're done. Phosphoric is also used as fertilizer for growing lettus. Run on over to the box store, and buy a bottle of concrete cleaner containing Phosphoric acid, and get the job done.

[agsem]

What about Ospho?

http://www.ospho.com/

It has been around for years.
I have used it.
It dries to a paintable black surface.
Available at retail building supply outlets.

Thanx,
Greg Hayden

[Franz©]

Ospho, according to their website is a mix of "SKYCO OSPHO: a balanced formula of Phosphoric, Dichromate, Wetting Agents and Extenders . .
Phosphoric acid has already been explained. It is the active ingredient in Ospho, and does the work.
Dichromate, could be one of many dichromates, in the world of chemistry, often used as an oxidizing agent in fireworks.
Wetting agents - dishwashing soap is a wetting agent, it just allows the liquid to travel better thru the rust.
Extenders - a fancy word for water in this case.
Without access to their secret formula, you're paying close to 20 bucks a gallon for 11 ounces of phosphoric acid and 117 ounces of water, with about 1 drop of dish soap. If you factor in the price of the jug, you're overpaying by 17 bucks a gallon.

[Scott]

I use vineger 50/50 with water to clean the rust off my cast iron skillets.