OSPHO Rust Inhibitor in gas tank?

Tue Mar 25, 2014 9:43 am

I don't want to hijack the rusty gas tank post by Jason_Cofey so I've started a new one. In one of those responses I noticed that someone referred to phosphoric acid treatment. I have used the OSPHO phosphoric acid solution on rusty metal for several years with good results but not on the interior of a gas tank. This product chemically reacts with the rust (iron oxide) to form a paintable surface so I've considered trying it inside the fuel tank. Anyone have any experience or thoughts about how this might react with gasolene? Thanks, StaninlowerAL

Re: OSPHO Rust Inhibitor in gas tank?

Tue Mar 25, 2014 10:30 am

I have never tried it, but the Metal Prep that POR 15 sells as part of their fuel tank restoration kit contains phosphoric acid.

Re: OSPHO Rust Inhibitor in gas tank?

Tue Mar 25, 2014 11:49 am

buy a gallon of muriatic acid, swish it around the tank, it will eat the rust until its clean inside, do not leave it in there any longer than it needs to do the job,,then fill with water and baking soda to neutralize the acid so it does not keep eating the metal, swish it around more and flush clean with water, dry out the tank and I like to spray light oil or penetrate oil in it as with this clean virgin finish it can rust quickly, acid is cheap and the baking soda, also kills off the poison ivy when I am done cleaning the tank with it
Tim

Re: OSPHO Rust Inhibitor in gas tank?

Tue Mar 25, 2014 12:05 pm

tst wrote:buy a gallon of muriatic acid, swish it around the tank, it will eat the rust until its clean inside, do not leave it in there any longer than it needs to do the job,,then fill with water and baking soda to neutralize the acid so it does not keep eating the metal, swish it around more and flush clean with water, dry out the tank and I like to spray light oil or penetrate oil in it as with this clean virgin finish it can rust quickly, acid is cheap and the baking soda, also kills off the poison ivy when I am done cleaning the tank with it
Tim


This is the method I like. If you have any old gas sludge in there run some lye through it first. Only thing I did different was dilute the acid some with water and let it stand overnight--seems like the formula was a cup of muriatic acid per gallon of tank capacity and then fill with water.

This method involves some pretty nasty chemicals but it sure does work. Only use the "slosh a handful of nuts and bolts around" if you hate yourself!!

Al

Re: OSPHO Rust Inhibitor in gas tank?

Tue Mar 25, 2014 12:13 pm

Super A wrote:
tst wrote:Only use the "slosh a handful of nuts and bolts around" if you hate yourself!!


:lol:

I was thinking I could just strap my gas tank to the rear wheel of my other cub like this video. :mrgreen:

https://www.youtube.com/watch?v=Uz0QNEtm5fQ