What's the best for cleaning rust out of tank?

[Snakeoil]

Rob,

What strange alchemy "leaves behind a zinc oating" when you let phosphoric acid dry on steel? There is no zinc in the acid or the steel.

Wilf

Wilf,

You are 100% correct.

I have no idea why I typed zinc. Senior moment I guess. It leaves a phosphate residue, Iron Phosphate if I remember right, that is pretty stable and provides the corrosion protection. That is the blue/black compound that appears to replace the red/brown rust.

Glad somebody was paying attention. My apologies for the error. Seems to me I've made this error before when discussing tank cleaning/coating with others. I must have some kind of bug in my alleged brain that makes me type zinc coating when I just want to type coating.

Sure would be nice if you could galvanize the inside of a tank by sloshing some stuff around, wouldn't it?

Thanks and regards,
Rob

[Wilf]

Rob,

Yes, it would be very nice indeed to be able to zinc plate a fuel tank by simple sloshing! It is possible, but not at all simple on a Super Hawk tank.

The black residue after phosphoric acid treatment is only moderately effective in reducing further rusting because it is porous and not mechanically strong.

By the way, I am currently working on an algorithm that would permanently excuse seniors (especially myself) from the need to apologize for "a senior moment", aka "brain fart". It's quite complex, involving formulae for age in days, senior days minus days hung-over, conversion of moments passing wind to days, and an elusive factor involving the wisdom of the aged. I'm close to getting it right, but unfortunately I personally still come up shy of the exemption threshold!

Wilf

[Snakeoil]

Rob,
By the way, I am currently working on an algorithm that would permanently excuse seniors (especially myself) from the need to apologize for "a senior moment", aka "brain fart".... I'm close to getting it right, but unfortunately I personally still come up shy of the exemption threshold!

It's a noble cause, Wilf, but the audience upon which you would apply it does not have the attention span to grasp it. I have found that a simple "Wha???" with a deer in the headlights look on my face suffices for pretty much any screw-up I'm responsible for, whether that be at work or out with the general public.

The beauty of age is you deal with your limitations. Instead of remembering all the BS that comes into your life, you manage to use what few remaining synapses that continue to fire to remember important stuff like the the valve clearance for your scrambler or how to fabricate an unobtainable motorcycle part from 2 pieces of garden hose, a feminine napkin and an old muffler clamp.

Forget the equation, bud. We are old and we make mistakes, say dumb stuff and mix things up. All I can say about that is it is something for the younger generation to look forward to. respectfully submitted,

Rob

[Glenardo]

I've used different brands of phosphoric acid on rust with great results. The best brand I have found is Picklex. http://www.picklex20.com/index.html but it's very expensive, $75 for a quart!!!! So I use it very sparingly. I wanted to test the $20/gal Evaporust, and found it's slow but effective.