Etch Prep

[MisterCinders]

Just picked some up for my tank. Been through three rounds of vinegar, but I cannot beat the flash rust.

The directions call for diluting with three parts water to prep metal. Is that right for the tank, or should I go stronger?

[old_skool]

Everyone has their own method, but here's how I did it, I used the same stuff, full strength, with approx 20x10mm nuts inside, all sealed up, rotated ever couple hours, poured it off after 24 hours, filled with water to de-activate any remaining acid, the prep and etch will coat all bare metal nicely if you use full strength, but following the water rinse, I used denatured alcohol, to absorb any remaining water,dumped and added a quart of WD40 for a second flash proofing coating, dumped, then filled with fuel, I always use a fuel filter, and this one hasn't shown any signs of clogging at all, and my tank had some serious flakes and rust inside.

[Nessism]

I'd use it full strength and leave it in for an hour or two, rotating every so often. The phosphate sauce will leave behind a coating that should retard flash rust. As soon as you rinse I'd hit the tank with WD-40, unless you are going to coat it, in which case the flash rust won't hurt anything.

[MisterCinders]

Went with only a slight dilution, adding about a half gallon of water to stretch it out a bit. Rotating the tank from time to time.

I thought the phosphate residue was good. Do I still need to rinse the tank out?