Preventing Flash Rust…IMPOSSIBLE!! (prove me wrong)

Hi everyone,After having de-rusted quite a few tanks I have come to the conclusion that preventing flash rust is IMPOSSIBLE!
Maybe you can prove me wrong with a detailed procedure (no anecdotal evidence will be accepted).
My situation:  I live in southern Calif about 4 miles from the beach.  We are considered a relatively arid area with not a lot of rainfall.  Yesterday the humidity was around 60% with the sun shining.
My Procedure:  I derust using Evapo-Rust or ≈ 40% Phosphoric acid (Klean-Strip Metal Prep).  Both work real well as a derusting agent.  In the past I have used Muriatic Acid, White vinegar and probably other solutions I don’t remember. After derusting I rinse well and here is where the trouble begins…  I remove most of the water and then try to remove any residual water with a solution.  I have used 91% Alcohol and WD40 both of which are supposed to absorb water, all to no avail as the tank still flash rusts.  Now the finished product is still way better than I started with but there is still some surface flash rusting.
Your Challenge… Provide me a detailed procedure to prevent the flash rusting I always seem to get.  Game on. 
Now maybe if I lived in Arizona or the Mojave desert with single digit humidity in the heat of summer I might be able to accomplish the goal. But not practical
I have considered going directly from the Phosphoric acid bath directly to adding gasoline but not sure what this would do.
Thanks guys,  Z

I flush with water, then fill with gas and a container of HEET. It's supposed to absorb water. I'm not sure if I drained that immediately or just ran it, though...unsure of how much per gallon will still run okay. 

P.S. - I think trying to dry it or get all the water out is a bad move - in my experience it doesn't rust as fast when wet. 

Being by the coast is not helping you. Salt in the air is gonna fight you.

Use distilled water.
This will help but probably won't
completely solve your problem.

Turn on your air conditioner to drop the humidity.

Maybe spray it down good with WD40 (and a shot of 3 in 1 oil) right away after the final rinse.

Blow dry it with compressed air! Or mix real acetone from a collision supply house with water, it mixes! not nail polish remover! Then it will evaporate.
Never use WD-40!! It is for a woman's junk drawer in a home! It's for hinges and drawers! It's 40-50% water to begin with!
That shit sucks! Plain and simple!!!!!
It's a gas tank! Blow it dry! Buy a quart of Marvels Mystery Oil! $5.00-$6.00 depending where you live or store? Pour it in and coat it!  Roll it around! Play with it!
Leave it in for a few days. drain good before you paint tank?
I'm 63, I learned painting and to use Marvels since I was a teenager by the older guys I hung around with. It's in every gas tank I ever had! My 1975 Harley Shovel Head still has the original soft valve seats made for leaded gas. I've been thru 2 sets of valves in 40 years, but never did the valve seats.
Just My Opinion!
At least this is what I do.

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Buy a quart of Marvels Mystery Oil! $5.00-$6.00 depending where you live or store? 
It's in every gas tank I ever had! My 1975 Harley Shovel Head still has the original soft valve seats made for leaded gas. I've been thru 2 sets of valves in 40 years, but never did the valve seats.
Just My Opinion!
At least this is what I do.

Marty, do you add it to the fuel? How much per gallon?

Marty, speaking as a woman that uses WD-40 for clutch/throttle cables, throttle tubes, my chain, and pretty much everything else that I can...I don't really agree. I sprayed a bare engine block with WD and 3 years later when I dug it out, no rust. 

That being said, it isn't my first choice for this topic. I'm just kind of irked. 

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Marty, speaking as a woman that uses WD-40 for clutch/throttle cables, throttle tubes, my chain, and pretty much everything else that I can...I don't really agree. I sprayed a bare engine block with WD and 3 years later when I dug it out, no rust. 

That being said, it isn't my first choice for this topic. I'm just kind of irked. 

 

That's no surprise at all!  The engines on the KZ bikes are made of an aluminum alloy, so no matter what they cannot rust.  Rust occurs on ferrous metal, not aluminum.  Ed

I use phosphoric acid, Kleen Strip Etch and Prep, to derust.  If you leave it in the tank for a couple of days, shaking the tank every time you remember and rotating it through various positions, it will coat the metal with a thin film which retards rust. After all the rust is gone dump it out and recycle since it can be used again and again.  Now get your hose ready and rinse it quickly.  Shake the tank as hard as possible then dump out the water.  Next is a quart of IA.  Shake and dump.  Then half a can of WD-40.  Again, shake to make sure the entire tank is covered and dump.  There may be some very light flash rusting left behind but it will be very minimal and nothing to worry about.  WD-40 is poor at long term protection but it displaces water well, thus the WD name, and it will hold off the flash rust.  If you want more lasting protection fill the tank with some gasoline or dump in some motor oil and coat the tank with that.  

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Marty, speaking as a woman that uses WD-40 for clutch/throttle cables, throttle tubes, my chain, and pretty much everything else that I can...I don't really agree. I sprayed a bare engine block with WD and 3 years later when I dug it out, no rust. 

That being said, it isn't my first choice for this topic. I'm just kind of irked. 


 

That's no surprise at all!  The engines on the KZ bikes are made of an aluminum alloy, so no matter what they cannot rust.  Rust occurs on ferrous metal, not aluminum.  Ed

"a bare engine block "

You've made the assumption that "A" bare block was a Kawasaki engine, I read it as a cast iron block seeings though we are talking RUST.....

I'm in Richmond, VA. and have de-rusted 3 tanks in the past few years, using acid once and vintager twice. and have not had flash rust problems.
Immediately after pouring out the vintager/acid, fill and flush the tank several times with water. Drop a cloth rag int the tank and shake around. Remove rag and repeat until rags come out dry. Then put a blower/vac tube into the tank and let it blow for 30min until tank is completely dry.
 

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Marty, speaking as a woman that uses WD-40 for clutch/throttle cables, throttle tubes, my chain, and pretty much everything else that I can...I don't really agree. I sprayed a bare engine block with WD and 3 years later when I dug it out, no rust. 

That being said, it isn't my first choice for this topic. I'm just kind of irked. 




 

That's no surprise at all!  The engines on the KZ bikes are made of an aluminum alloy, so no matter what they cannot rust.  Rust occurs on ferrous metal, not aluminum.  Ed

"a bare engine block "

You've made the assumption that "A" bare block was a Kawasaki engine, I read it as a cast iron block seeings though we are talking RUST.....

Considering that it stated "..... uses WD-40 for clutch/throttle cables, throttle tubes, my chain,...." I believe the machine in question is a motorcycle.  I could be wrong, but I don't know of recent cars or trucks that use a chain, throttle tubes, etc.  Ed