Petrol tank sealants

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About a year ago I lined my steel Interstate tank using Flowliner from Wyldes of Leeds. After a week or two it started flaking off and dissolving in the fuel, gumming up the carb with sticky yellow stuff. A short time before this I had lined two Dominator tanks with the same stuff and so far it seems to be OK. However, I see that the Flowliner website now states the material should be applied as an "even coating of around 2mm. Anything less than the recommended thickness may fail especially with the recent addition of ethanol to fuels." I don't remember being made aware of this at the time. It sounds to me like an admission that Flowliner isn't ethanol-resistant, and it's a great get-out because how can you prove you've applied it thickly enough.

I now want to line another steel tank and obviously I'm going to avoid Flowliner like the plague. The question is, what to use?

Searching this forum came up with several recommendations for Hirsch sealant, which although a US product is available in the UK (RatSport, Moss). The only reservation I have is that it is soluble in MEK, and not knowing what nasties are lurking in petrol nowadays I'm concerned that some fuels may contain MEK or something similar. After all, Hirsch sealant is advertised as having been around for 40 years, but fuel composition has changed a lot in that time.
A similar consideration applies to Petseal, which a lot of people are rubbishing now, though it seems to have been used successfully in the past, before ethanol. Petseal Ultra is stated to be resistant to ethanol and suitable for lining over old Petseal, so it seems that the makers have addressed the problem and aren't content just to say "it's been used for donkey's years so it must be good".

I was going to try POR 15, but although it seems chemically resistant it apparently has a habit of coming unstuck.

Caswell epoxy sounds very much like Flowliner, so I have obvious reservations in spite of good reports. The same applies to Tank Cure epoxy.

Anybody know anything about Vintage Car Parts resin in solvent based fuel tank sealant? Is it Hirsch under another name?

I've also rejected PR1005L rubber coating (Tank Care Products, Merlin Classic Motorcycles) because I turned up a comment on http://www.ajs-matchless.com stating that the manufacturer has confirmed that PR1005L is NOT suitable for use with the increased ethanol in pump fuel.

So, Petseal Ultra or Hirsch? I expect the US folks will say Hirsch, but has anybody here from the UK tried Petseal Ultra?
 
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+1 on the Caswell product. Follow directions EXACTLY. I applied 2 coatings to my 70's-era Dunstall tank and everything's perfect after 2 years now.
 
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I think at this point for steel or alloy tanks I would just clean the daylights out of them and keep them full to avoid condensation. Still waiting for a miricle cure before doing my Prody glass tank. I have a friend who is doing a bunch of expirements with differant stuff but they all have one problem or another. Good luck.
 

maylar

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I have the Bill Hirsch white stuff in my steel tank and I'm very pleased with it after about 6 years.
 
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Currently have three tanks that I've given the POR 15 treatment to. Not for any leak fixing, but to keep the top half from getting rusty. So far, I've got ten years on one, eight on another, and 5-6 on the last one. Carefully prepped, not a bit of the stuff has come off. I've owned both Harleys and steel tanked 70s BMWs that had some kind of reddish paint inside the tank. It always stayed put, the tanks never got rusty, and so far the POR 15 is holding up just fine. I don't think there is a single type of tank sealer that I've read about on this or other forums, that someone hasn't had come loose, curdle up, or make a mess of things. Like I said, my preparation was fussy, bordering on ridiculously a**l, but it worked. YMMV.
 
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I have one tank lined with Hirsh BUT I have been told by someone on this forum (by phone) that he had many tanks to fix that were sealed with Hirsh. According to him, Caswell is the stuff I should have used. Now for the life of me I can't think of any good reason to coat a steel or alloy tank IF the bike is used on a regular basis AND no fuel is left in the tank when the bike is stored. To me only fibeglass tanks should be sealed, especially if the resin is not alcohol resistant.

I have read about gas with alcohol separating and alcohol being hygroscopic (the main reason a drink made with scotch and water does mix) would fall to the bottom and eventually rust trough a steel tank and do some nasty stuff to alloy, but by riding a bike, the two fuels would get a good shaking and mix, we even did this years ago on cars during the winter, we would pour a little alcohol in the gas so it would mix with the water that accumulates in gas lines, mix with the gas and burn. Rusted tanks in cars were never a concern, so stop being scared about everything, enjoy life and ride!

Jean
 
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I used Hirsch last week so will find out in a while how that does.
I chose it because Hirsch is a well respected brand specializing in products for automobile restorers, has been in business a long time and specifically states their sealer is resistant to fuel with alcohol.
System is cleaner, etcher and sealant.

Bob
 
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I'm only lining the thing because it's leaking - it's long past the "keep full of fuel and prevent rust" stage.

I take the point about careful preparation being the key. When I did the Commando tank with Flowliner I used their Solwash in an attempt to get the tank thoroughly dry, but I wonder if traces of Solwash left in the tank were the reason the epoxy didn't stick. Still doesn't explain why it dissolved, though. I haven't read anything to suggest that POR 15 dissolves, and at least if it's basically a paint it should be easy to remove with methylene chloride.
By the way, if anyone's thinking of using Flowliner Solwash, it's an effective paint stripper, so take care.

Understandably, I'm now a bit wary of epoxy products, and I wonder if Flowliner is just Caswell re-badged (as I have read Moss is Hirsch re-badged)?
At least the Restom sealant is advertised as being suitable for unleaded petrol with 10% ethanol, which is a level I don't think we've reached in the UK yet, so I'm leaning towards that at the moment.
Still no reports of Petseal Ultra?

Incidentally, it just occurred to me to wonder if US and UK/Euro fuels are the same. AFAIK, Europe now has up to 10% ethanol, UK 5% (with 10% on the way), what about the US?
 
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Seems to me there was a post in one of these tank sealer threads from someone who did some tests on US gas and found much higher levels then the stations said they were using. I also heard from a friend who is trying to find a reliable sealer that they are going to be using a higher percentage here in California soon.
 
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gtsun said:
Seems to me there was a post in one of these tank sealer threads from someone who did some tests on US gas and found much higher levels then the stations said they were using. I also heard from a friend who is trying to find a reliable sealer that they are going to be using a higher percentage here in California soon.

I know a lobbying group has been trying to stop ethanol blends going from 10% to 20%. Seems like it was a small engine lobbying group of some sort. As I've posted on here before, I use Amoco Ultimate, and they clearly state on the pump that there is no ethanol in it. Most of the stations in Nebraska that have three grades regular, mid-grade, and premium, only say the mid-grade has ethanol in it. The regular says 87 octane, mid-grade (or silver) has 89 octane, and premium has either 91 or 92 depending on brand.

As an aside, I saw a posting on a BMW forum where people would bring a calculator to the station with them. They used it to see which one of the pumps has just had premium run through it, by backing through the price and gallons, and avoiding any leftover ethanol blend in the hose. I've heard of being cautious, but that takes it to the paranoia level!
 
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