tank cleaning

why is phosphoric acid better than muriatic acid for cleaning tanks? i am getting ready to clean one and thought i would ask to get a better understanding. thanks.

From a chemical standpoint, can't say. Muritic acid is used to etch concrete. Phosphoric acid is used to treat light rust. They use it on bridges and stuff and it causes surface rust to go dead or inert, as I understand it. Anyone that paints metal, like metal fences and such, uses phosphoric acid... not sure if the muritic acid deaden rust or not. I have never tried and have always used phosphoric acid on ALL vintage bike tanks I have owned that have had interior surface rust.

I used muratic acid to clean my tank, only 5.00 for a gallon down at fred meyers, worked awsome tank was spottless and then so was my driveway, only problem was when it was drying it got a light coat of surface rust due to the fresh bare metal, I heard that phosporic acid leaves a coating behind that wont do that but that it does not work as well if your tank is really bad. I usede something coalled red kote for the coating, baught it at a local radiator shop, it worked awsome

My understanding is that the phosphoric acid leaves behind a layer of iron phosphate which is supposed to be a protector. Iron chloride, which is a product of muratic acid (HCl)is soluble and doesn't protect.

Patton suggested WD-40 to stop the flash rust. In the past I've used muriatic acid to attack the rust and scale followed by phosphoric acid to leave a coat of iron phosphate. On the last tank I did I sprayed WD-40 into the tank as soon as I drained out the phosphoric acid. I then flushed well with water and then with more WD-40 to seal out the oxygen. I finished by forcing it dry with a hairdryer and it's totally rust free today.

KZCSI

rust never sleeps.............

well, i got the red kote. looks like i'll be going to phosphoric. after using phosphotic acid, do i still need the red kote? or will the iron phosphate coating left behind be enough?

When I was with the militia, the Red Coats were the enemy... whatcha talking about? red kote? (btw: I was making a joke... I ain't quite that old hehe)

The phosphate coating should be fine.

Post edited by: arai60, at: 2007/06/23 23:43

Post edited by: arai60, at: 2007/06/24 10:01

wiredgeorge wrote:

When I was with the militia, the Red Coats were the enemy... whatcha talking about? red kote? (btw: I was making a joke... I ain't quite that old hehe)

its a tank liner i picked up from an auto parts store. called redkote. or something like that!

I coated my tank with Red Kote, from what i was told it's a polymer almost like rubber and doesn't flake or crack like other sealer can. I put some of it on a piece of cardboard and was able to bend it without cracking after it was dry.

After I was done with my tank, bondo/primer, and cleaning with muriatic acid, phosphoric acid, flushing with acetone and treating with Red Kote I decided to go with a larger tank. :woohoo:

The tank I have now is from I believe a police KZ which was treated at some point with a sealer like Kreem and is now flaking off ( probably not done right ).

If you already have the Red Kote I would use it, there really isn't much to applying it once the tank is cleaned inside, just make sure the tank is dry, that all being said you should be fine with just the phosphate coating.

phospate




red kote

[img size=499]http://members.cox.net/bbruni/red kote.jpg[/img]

cool. thanks for the pics. i would rather not line it if possible.