Flash Rust Prevention After Rust Removal

[Rouge Rider]

Just finished soaking my gas tank with Vinegar and now it nice and clean. The problem is: Once I flush it how can I prevent the flash rust which I know will happen. I am thinking aerosol fogging oil or just WD 40 or something I can find locally. Important, I won’t be installing the tank for another few days, so I don’t want to fill it with gas. Appreciate any suggestions

[RideThis]

I'm in the process of restoring an old Honda, absolutely disgusting fuel tank... My first attempt to restore the tank was a mixture of muriatic acid and hot water and then rinse out, then I learned about flash rusting.

Lots of recomendations for a product called Kreem or POR-15, I chose to orderd POR-15. But I havent tried the product yet because it just delivered. I'll know if it works well by Thurs or Fri.

The cycle tank restoration kit from POR-15 was just under $80 shipped btw but you may just want the tank sealant.

[Freestyle72]

WD40 should do the trick for you.

[caboose483]

Aerosol cylinder fogging spray ought to work too. I have done this with my spare tanks that sit empty.

Spray in from the fuel filler, also remove th fuel pump and spray in from the bottom of the tank. Turn the tank over end-to-end and side-to-side so that any liquid spray build up can coat the inside of the tank.

[Rouge Rider]

Thanks for the responses sent. Here is the REPORT BACK WITH AN OVERVIEW OF THE PROJECT.

Here is the result of my gas tank rust removal project. Done on the cheap and totally effective. Should mention the rust was minimal:
(1) Flooded the stuck gas cap with W-D 40 and gently tapped and prodded it for almost 5 days. Finally the key cylinder gave a little then did the full turn a day later. Was just on the verge of drilling it out. Patience paid off.
(2) Plugged Petcock and expansion holes and topped up tank with pure white vinegar bought at NO Frills for $1.97 each. I added a half cup of table salt and sloshed it around for two days. Damn.. on day 3 it was like brand new inside.
Posted a question here on GTAM for suggestions on Flash Rust

(3) Emptied the vinegar, and totally flushed it with baking soda and a garden hose. Maybe two or three rust flakes floated to the top during the flush.
(4)
(5) . Fogged it totally with WD-40 (complete can) then mixed 20 / 30 engine oil with gas 70/30 mix ( 70 gas/ 30 oil ) sloshed it around end to end side to side. Totally coated. No sign of Flash Rust.
(6) Project complete: Results: 100% satisfied.

[RockerGuy]

I would say 3-4 tablespoon of motor oil mixed with 200ml of gas would have done the trick.
Swirl it around.
Optional: let the gas evaporate and the motor oil will be left coating your tank.

Motor oil have been pretty effective in combating rust for me