Harley gas tank sealer

[panmandan61]

Any recommendations on best gas tank sealer products?

thanks,

[PaulCDF]

I like Red-Kote for steel welded tanks.

[exeric]

I only use Red-Kote but that's the same as people who prefer Vitalis, to Pomade, to aue naturle !

Red-Kote seems to hold up to gas, and can be removed with MEK, acetone, or paint remover if you want to have a change of heart and go the mechanical route with welding, solder, and lead filler which is the best, but most gruesome fix. . . Nothing seals, or stops leaks on the outside of a tank so don't waste your time with any product that promises that*. . . . And don't forget to pressure test the tank before painting.

*p.s. Other than welding, solder, and lead filler.

[Buster]

My recommendation is to not use any type of sealer. Solder it.

[otis71]

I agree on trying to avoid sealers. That said the only one I’ve seen to hold up over time is Caswell which is 2 part epoxy. With any sealer the prep is the crucial thing. Caswell adheres to rusty metal better than clean. The tech department recommends cleaning all loose and scaly rust and rinsing with acetone.

[T. Cotten]

Sometimes the search function almost works, Folks!

Over a decade ago, I finally was given some Red-Cote to test upon etched glass immersed in my local fuel: https://forum.antiquemotorcycle.org/...ers#post122674

It performed perfectly, whereas two varieties from Caswell's failed over a couple of months, and POR-15 always failed overnight.

I stopped testing for two reasons: The fuels are still constantly changing, and nobody learned anything anyway.

....Cotten

[chuckthebeatertruck]

I've been painting tanks since 1991. Dozens have come through my hands and unless I was instructed not to do so - part of what I charged for was/is lining tanks. Most of my personal bikes, unless original paint, are also lined.

From 1991 to circa 2010, I used RedKote. It was cheap, easy to work with, and available at auto parts stores (still is available over the counter at O'Reilly's).

I then switched to Caswell.

In the last 10 years, I've done about 25 tanks - 23 were Caswell and two were RedKote.

One of those bikes had a seam failure not a liner failure. The failure was due to my poor soldering; not the tank and not the liner. That was on a redkote tank. Had it been a caswell-lined tank, I doubt it would have leaked.

The reason is that I've personally seen the aftermath of a tank getting crushed, not dented, that was lined with Caswell. I was riding the bike and did the paint -- so I know exactly what happened and what products were used. Anyways, the forks destroyed both sides of the tank leaving deep creases extending the whole height of the tank. The tank had been in a severe accident decades before and was totally soldered back together . . .the soldered areas were the creased areas and the tank would have been pissing fuel out like crazy without a liner.

Instead, when I looked inside after draining the fuel (weeks later), the liner had distorted with the crease. It was cracked and crazed, but held fuel. The tank had no physical integrity to hold fuel -- only the liner was still holding it in.

YMMV

[exeric]

How did you remove the Caswell liner prior to a mechanical fix? The alternative with modern tanks is to replace them, however with early tanks like I mess with, it is very difficult, expensive, and hard to find a replacement. I agree that a liner is important and I believe Caswell makes good products so I would be open to using a liner by Caswell. The pictures are of an Excelsior tank that had numerous pin-hole leaks and my first neophyte attempt with 'Kreem' proved disastrous, so, I used paint remover to get the Kreem off, followed up with MEK to rinse the residue, and then lots of harsh detergents, and hot water baths. As shown, I had to resort to cutting an access hole in the tank to sand blast the inside, and lead patch every pin-hole I could find. the mechanical fix worked, but Red-Kote was good insurance, and worked very well. Tank liners can be a wonderful, easy fix for a tank that is in good shape, or post V series tanks that are welded and of heavy gauge steel.

tk4.jpg tk5.jpg tk7.jpg

[otis71]

I did a JD tank that was extremely porous over 10 years ago with Caswell and it still held when I recently sold the bike. Caswell does recommend not to use marvel mystery oil with their liners.

[T. Cotten]

If it were not for the everchanging digestivity of fuels and additives, Folks,

And the synergistic effect of mixing brands (such as on a trip),

We could all still be using shellac.

....Cotten

[chuckthebeatertruck]

Eric, you hit on the one big challenge of using Caswell. If a mechanical repair is needed - the epoxy based liners like Caswell become a liability.

Almost all other liners on the market can be dissolved with MEK or DMC/toulene and patience. RedKote is the most friendly in this regard and you can easily remove it with MEK. Kreeme tends to be the hardest to dissovle; it simply breaks up and comes out in chunks.

Caswell, however, is truly household chemical resistant. What it can't resist is the one commercial chemical that eats all paints and epoxies for fun: Methylene Chloride. So you could easily dissolve Caswell in MC. MC used to be everywhere and very cheap. It's also a serious impediment to human health no matter what you do and so MC is no longer available in any product of any type sold in the US.

This means the only viable solution today is mechanical removal -- which means cutting open the tank and blasting.

Caswell, as Otis points out, was one of the only companies that also had clear warnings about specific types of fuel additives.

This is because those additives contain chemicals that either are MC or will become MC-like when combined with other petro-chemicals. They specifically called out MM oil and Lucas Fuel Treatment for these reasons. This was an even bigger challenge when fuels contained MTBE (1979-2004, some areas until 2015) as it amplified the effect. And a surprising number of things had some trace of MC in them.

However, none of it is really applicable because Methylene Chloride is fully banned in the US as of January 1, 2024 and the last commercial products to contain MC became illegal for sale on January 1, 2019.

Personally, I never paid any attention to the warnings and I haven't had a reason to revisit that decision. I don't use MM oil often and I don't use fuel additives often - so it just isn't a concern for me.

YMMV