My buddy bought a V-Star with 12 miles on it, sitting for two years...
Tank is so rusted, we couldn't get the cap off...  So, now the cap's off... and the tank is full off rust.
Carbs cleaned, lines and petcock replaced,...

But that rusty tank....
Any ideas?...

that may work, but if it looks pretty bad i'll bet not. go to your local wal mart or equivelent. buy some WORKS toilet bowl cleaner. one bottle should do it. if not, they only cost about a dollar. youll need to plug the petcock hole. i usually throw a few screws in the tank first, shake it around really well, then with a long magnetic screwdriver, take them back out. now for the fun stuff. pour in a bottle of the works, then fill the rest with water. let it set. i have let them set over night with no ill effects. the next day, pour the mixture out (according to EPA regulations ) then rinse the heck out of it with water, i have done it about ten times. i would recommend sealing the tank with por 15 expensive, but worth it.


disclaimer, the works is ACID so be careful. by doing this, you take full responsibility of your actions. WEAR RUBBER GLOVES!!!!

now back to our regularly scheduled programing  

Bill Hirsch products has been the leader in the automotive restoration industry for many years.  They sell a kit to remove the rust and seal any gas tank.

I've used the gas tank kit in a number of vehicles, and it works perfectly. Its well worth the $30.00.

http://www.hirschauto.com/prodinfo.asp?number=CRK-01

& If you dont want to spend the $$$ on a kit, $12.00 for a quart of Ospho will kill the rust left in the tank after the shaking & rinsing. Phospric acid turns iron oxide into iron phosphate, doesnt cover it up, kills it..& youll have nearly all of it left over, it only takes getting it wet.

Thanks for all the ideas guys,... I'll print'em out and pass them on...
Serowbot  

srinath wrote on 10/02/09 at 06:16:25:


Srinath,
   Just looked at the Rustol MSDS.  It says ita a Aminopoly Carboxylic Acid derivative.  Do you know anything about that chemical?

TMack 1

Phosphoric acid attacks nonferrous metals such as brass, bronze, copper, etc.  Any brazing will start to dissolve when submersed in phosphoric acid.  I know, because I watched it happen overnight  on a rusted steel item that had been repaired with braze.   Phosphoric acid will change the temper of the surface of iron or steel, which is why you don't use it to remove rust from springs.  I'd think real carefully about submersing a bike frame in it because the temper of the welds as well as frame temper will be affected by Phosphoric acid.  Also, it is really bad for your lungs, and will burn your skin:

http://www.jtbaker.com/msds/englishhtml/P3973.htm



I stopped using Phosphoric acid because of a product that was introduced some years ago and works just as well, though not as fast.  I use "Evapo Rust" instead and although it takes 3X longer to do the job, it always removes rust completely when an object is submersed in it.  I Prefer it because it's easier to ship through the mail or UPS, it doesn't attack non-ferrous metals, and it doesn't burn your skin or eat holes in your clothes.  The fumes don't burn you eyes.  Its a fairly safe product to handle.

http://www.evaporust.com/evaporust.html

You still need to quickly seal the tank after you remove the rust because it will immediately start to rust again as soon as moisture in the air or water in your gas, hits it.  Thats why the $30.00 Bill Hirsch kit is is convenient.  Everything you need is right there and it works perfectly.

Muriatic acid does give out chlorine. However it eats rust so fast, and gets diluted in the process - you toss in a pint in a 3-5 gal tank, seal all holes with duct tape and 2-5 mins of shaking and you're done. Dump it on your driveway (away from all metal objects) and toss baking soda on it and water from a hose and you're done.

The thing is available 2 gal for 10 bucks @ home depot.

Phosphoric acid is a lot less toxic but it is messier at the end. And hard to finish the job in a closed in space.

I dunno about any others. Oh, POR15's acid is a close cousin of Phosphoric acid.

I agree on the quick sealing of the tank after muriatic acid, but that time is in the order os 10-20 mins not in the order of seconds.
If your tank will drain dry, or drian 90% dry and you have good access like a savage tank 20 mins is plenty of time.

Sealing against acetone has to be done with inner tube and petcock and a rubber stopper on the mouth, you have to keep it plugged up good.

Muriatic acid in the time you would slosh it will not get out in any quantity to hurt paint. Sealing wiht duct tape should keep it 99% inside. Few little runs etc should be wiped and be OK.

Honestly I have had far worse than muriatic acid. If you're afraid of it full strength, dilute it 2-10 times. But then you have to seal it tight because it will need more quantity and more time. Inner tube inside petcock works for that as does rubber plug @ cap.

Muriatic acid's strength is its biggest strength, forgive the pun. Its very very quick acting.

I'll happily do it for you - POR15 or Kreem, but in a way it depends on the tank design as to what is best.

BTW take it from me - and I have the virago tank to prove it, if you are powdercoating it after wards, you need to do POR15. Not Kreem. It cant stand 450 degrees.

Cool.
Srinath.