Fuel tank sealer

I am getting my tank ready for paint and can't decide if I want to do the sealer coating.
I just had bad luck with kbs sealer in my original tank that was pretty rusty inside.
I did everything correct but it ended up rusting under the coating and peeling off.
I have had seen other tanks with different brands peeling off too.
The new tank had very little rust so I flushed it with rust removal gel and cleaned it with acetone.
Now it's like new.
I have cream sealer and Eastwood sealer sitting on the shelf but I'm afraid to seal it , especially a rust free tank.

I would suggest if the tank is in good shape that you NOT seal it. My 1977 tank is original and has never had any sealant put in it (I bought my bike new in 1977). As long as one keeps fuel in the tank I believe it will never rust. The problem seems to occur when the tank is left empty and moisture accumulates in it. If your tank is not rusty I don't think it will ever rust as long as you keep fuel in it. Ed

Agree with Ed; no sealer. You might want to use a mirror and flashlight and look all over the inside of the tank to be sure there is no hidden rust. If there is phosphoric acid is what a lot of pro's use to derust and it works great.

I removed whatever rust that was in it with rust remover gel and flushed it out with acetone.
I checked a cool led light and mirror.
It's like new now. Just want it to stay that way.

I agree with the others. Don't seal it unless you have to. I've used sealer on tanks where the paint was more than the entire bike just for insurance.
If you must, use a two part sealer like Caswell.

I think I'm going to have to seal it.
I removed the light rust and the next day its covered with surface rust.
I'm not even exposing it to water and its not even humid yet.
I treated it and cleaned it out 5 times and no matter what I do it rusts up overnight.
I know that the factory galvanised coating must be gone , but I built tanks from raw steel and they never rust like this.

It may be rusting because it is empty. My 1977 KZ650-C1 tank has never rusted and never needed any kind of treatment or sealer, but I keep gas in it (I've owned the bike since it was new). Before you try sealing it why not try putting gas in it to see if it still rusts? Ed

What specifically did you use to remove the rust with and did you follow the directions? Some acids used to strip rust, such as muriatic acid, require neutralizing. Others like phosphoric acid don't. In either case water is typically used to dilute and remove, not acetone.

I first used acetone, then tried clr. then tried rubbing alcohol , finely last night I used 2 cycle gas with oil in it .
I used a few different rust removals.
Rustoleum gel that works great except I let it dry the 3rd time it rusted and was a mess to clean out.
I then used the tank sealer rust remover .
Yesterday I used a mix of them and clr. It worked good and was easy to clean.
I hate to seal it but the chances of me having a full tank all the time are nill.
Bye the way, I ended up tossing the freshly painted tank onto a rock yesterday while trying to shake it out. I'm almost ready to strap a plastic jug to the bike!

For sealing the fuel tank there are probably several good coatings available. Most failures are probably from poor preparation. You've already been doing it, but I did extra tank prep prior to using a kit. I would probably use the stuff from Caswell or KBS coatings or West Systems epoxy.

KZR topic: KZ 650 tank leaking behind badge - options? >> West Systems
Quote from the link by Jeff.Saunders of Z1Enterprises.com: What I've used on tanks that you can't seal using Kreem or Por15 is a marine epoxy resin to line the tank. West systems marine resin epoxy. 105 resin and 205 hardener. This mix creates a hard shell inside the tank that's impervious to gasoline. Use a 5:1 mix.

Here is the best sealer out! And I go back to using KREEM in the late 70's.
"CasWell.com" product. It is a 2 part Phenol Novolac Epoxy.
It actually like rust and scale. It gives it a substrate to adhere to better.
Phosphoric acid is good to use, I like the Home Dep rust remover gallon, about $17
And acetone mixes with water, and at the end of cleaning, it will all evaporate with compressed air.
I used it on a set of OEM Harley tanks from 1968 for my FLH.
Paid $49, This amount will do 2 Kawasaki tanks. In warmer air, (summer) when mixed has about 20 minutes work time.

I have Eastwood and cream .
I used kbs the first time on tank 1 and followed directions +. I think part 2 caused the rust between the tank and coating. Anyways it peeled off like wet drywall.
I don't trust the cream because the guy I got it from was showing me how great it worked on his harley tank and I showed him how it was flaking off under the fuel. He gave me it free.