The Stovebolt Site Forums The Shop Area Paint and Body Shop question on the muriatic acid trick

have any of you guys used it for the inside of a gas tank? or can you think of or know of any reason not to use it there. thats always the hardest place to get real clean before sealing.

Years ago I bought a perfect wraparound oil tank for a Panhead that the only flaw is that is was rusted pretty good inside.I had seen concrete etched with it when I was young and saw how it cleaned rusty rebar like new.I tried it,took 2 applications,came out like new inside.Then Sodium Bicarbonite and water rinse to neutralize it and immediately blow out with air and fill with WD-40 or the like to keep rust from forming,as it will almost right away.

Muriatic Acid (hydrochloric acid 31.25%) will dissolve your gas tank. Other than that I can not think of any reason why you wouldn't want to use it.

Unless your tank is made of plastic or hastelloy C276, I would not use muriatic to clean it.

Muriatic is good for dissolving scale from rust and calcium deposits on THICK steel and non critical parts as long as you know what you are doing. Putting it into a fuel tank and sloshing it around is not one of the applications that you'll find on the recommended list of things to do with it.

Use muriatic for cleaning concrete before painting/epoxy application, and for descaling your power plant boiler, and cleaning the brick around your fireplace, but keep it as far away from your fuel tank as you can.

ok you guys are confusing me...*L*....one says yes the other no..... I'm guessing that if I dont leave it in there to long it will be ok. I have a few old car tanks laying around to experiment with anyways.I've always been a try it and see kind of guy so I guess thats what I will have to do. stay tuned for an update

Is it true you can take your tank to some radiator places to have it boiled out? What do they use?

I dont see any reason you cant use muriatic acid on the inside of your tank. Just dont leave it very long it dosnt take much time. Rinse it out the use a baking soda and water solution to neutralize the acid. then rinse it again. Of course it will "flash" rust as fast as it dries. I uses it all day yesterday on my inner fenders and fenders with no problem. First time I did my fenders The acid seeped out of the seams no matter how much I rised. So I use the baking soda and water and wiped it down well and sponged it into the seems and cured that problem. Now with all that said Eastwoods sells a kit just for cleaning and sealing the inside of gas tanks. may want to look into that.

Now if its alunimum dont even get the muraitic acid close to it!

Good Luck!

Radiator shops boil in a soda solution. They used to use lye, not sure what they have now. We usually take the tank to get boiled, then we clean it good and use the POR-15 tank sealer. On cylinder tanks we set them on rollers and use small granite for an abrasive and tumble to clean the inside.

POR-15 says that if you follow their process, you only have to clean the tank out with their cleaner, removing the rust with other methods is not necessary. I've never done one that way, but I have no reason to doubt them.

I haven't used it on a gas tank but I have used Muratic acid extensively. Kooks right, you need to know what the metal is--if an alloy or aluminum--likely eat in right up. Sheet metal you can get away with it--if u neutralize it quickly afterwards. My radiator shop works pretty cheap--I'd be inclined to go there and get their advise. Gud luk.

Thanks for the info guys. I have plenty of scrap metal laying around. dont we all?, I will just have to do a little practice before trying it on the real thing.

I guess, it all depends on the water/acid dilution.
Last weekend I went to one of the family oriented home-centers and bought a gallon of concrete cleaner/etcher (hydrochloric and phosphoric acid) to clean the inside of my radiator.
After doing some experiments with various metals, I decided to use full strength, because the dilution seemed mild to medium.
I ended up leaving it to soak over night.
Removed about a cup full of scale and rust build up and the metal was practically like new.
Rinsed with washing soda and was ready to go.

I bought this radiator a little while ago, after it was sitting in a garage since the 50s.
I cleaned the entire engine cooling system using radiator cleaners from the auto parts store.
After a few trips on the freeway, on a very hot day, I noticed that it didn't cool down as well as my previous leaking one.
But after the acid soak the radiator seems as efficient as new.

Just goes to show how important it is to keep the coolant passages clean so the fluid can absorb the temperature of the metal more efficiently.

Since this cleaner seems safe for the softer radiator alloys, it should be safe on fuel tanks even in full strength.
But only careful experimentation can tell for sure.

After 30 years in the chemical business [working with mineral acids] I can only speak from experience.

'EXPERIENCE IS THE COMB THAT MOTHER NATURE GIVES US WHEN WE ARE BALD'