Fibreglass Tanks And Ethanol

[stickinthemud]

Just been reading an excellent article on the Mid Atlantic Vintage Trials club web site concerning an AJS project using one of Sammy's fibreglass fuel tanks.

The addition of 10% ethanol into petrol in Maryland USA has caused his tank to dissolve, leak and clog the fuel line and carb.

Anyone else had this problem? Apparently some fuels here in the UK (Tesco for one) have had 5% ethanol for some time.

Several other projects of interest on the web site too.

Edited December 28, 2008 by Stickinthemud

[big john]

I've heard of several old glass-fibre resin based fuel tanks degrade because of the modern fuels being more aggressive!

Big John

[bultaco49]

I regularly use an M85 Bultaco Alpina which has a fibreglass tank which I had noticed the fibre glass matting on the interior of the tank seemingly being etched into. I use both BP and Tescos unleaded with Castrol TTS and an octane booster. I contacted a specialist (to the racing trade) oils and additives supplier who was very helpful and confirmed that the additives in unleaded and especially in octane boosters would probably attack and degrade most commonly used fiberglass resins. Since then I have also lined the tank as the AJS rebuild with the Phenol Novolac Epoxy tank sealer available from Casewell UK and Casewell USA. There has been much discussion on this forum about this product and POR 15, another tank sealer. POR 15 is also resistant to modern additives including ethanol. POR 15 is not suitable for fibre glass tanks as even if it is properly prepared it will not bond to fiberglass resins. Unless there is another epoxy sealer other than Casewell I would, from experience, recommend only this be used. So far in both my Alpina and my slimline Sherpa tank (which I lined over 2 years ago) I have noticed niether etching or flaking and have had no fuel blockages.

I would line any fiberglass tank, even a new one as the seams are particularly vaulnerable.

Casewell recommend cleaning the tank with acetone but be warned - it will take the fuel resistant two pack an aerosol paint finish straight off!

You can read about casewell here http://www.caswelleurope.co.uk/gastank.htm

or POR 15 (for metal tanks) here http://www.frost.co.uk/ & search for fuel tank sealer

The people here http://www.opieoils.co.uk/ were very helpful about oils etc.

Tim

[b40rt]

Are any of the softer alloy tanks going to be affected by Ethanol etc?

[totalshell]

ethanol is nothing more than an organic alchol added at approx 5% to the vast majority of unleaded fuel in the uk ( all brands all suppliers) 10% in the US

Ethanol's hydroxyl group causes the molecule to be slightly basic. It is almost neutral like water. The pH of 100% ethanol is 7.33, compared to 7.00 for pure water.

so i find it difficult to understand how the fibreglass would delaminate or be 'etched ' by the ethanol as it is no more corrosive than water..

Edited December 29, 2008 by totalshell

[bultaco49]

Hmmm. Interesting chemistry there. However, we are not alone in wondering about Ethanol and fiberglass

Read this

http://www.boatus.com/seaworthy/fueltest.asp

[toofasttim]

Not ethanol but methanol.

Back in the days of apartheid and when sanctions were beginning to bite, the SA govt banned motorsport as a way of saving petrol. Never ones to miss a trick the motorsports fraternity jetted for methanol by simply removing the main jets. The result was that the methanol slowly ate through the fibreglass tanks of the sherpas and cotas of the time. One cota even caught fire as a result.

However I do remember that acetone was added to the methanol to make it undrinkable (tramps/homeless people were prone to drinking the stuff), what proportion of acetone was added I don't know and it could have been the acetone that was eating the fibreglass.

[mrpbody44]

E10 gas will destroy your fiberglass tanks even though you use Casswell and other sealers. I sealed my tank on my OSSA 350 trials bike and E10 destroyed the tank which was in very good condition.

You can get non e10 gas at you local marinas or use race gas in your bikes.

[swooshdave]

E10 gas will destroy your fiberglass tanks even though you use Casswell and other sealers. I sealed my tank on my OSSA 350 trials bike and E10 destroyed the tank which was in very good condition.

You can get non e10 gas at you local marinas or use race gas in your bikes.

Is your OSSA tank sealed with Caswell?

I have one tank that was sealed with what I believe was Caswells. No problems. I would recommend this over anything else.

I sealed two others with POR15 and am not as happy with the results.

One area in which this is an extremely well known problem is in the boating world. Apparent fiberglass fuel tanks were not that uncommon.

[mrpbody44]

The OSSA tank was sealed with Casswells sealer. On the Yahoo OSSA board there were some photos of an OSSA GP III tank that had the same problem and the guy cut the tank apart and removed the sealer which turned orange. He then re glassed the tank.

Just race gas for me now

[slalom_specialist]

Part of the problem is that most fiberglass tanks are made with polyester resin which is more susceptible to the additives in modern gasoline. (its not just the ethanol)

As a general rule it's not as much of a problem when the tank is built using epoxy resin such as in most carbon fiber tanks, but even with the epoxy resin, there are still some additives that can cause a problem when you use modern pump gas. (Which is why you see failures even with the use of epoxy sealers) Unfortunately, the oil companies are very secretive about all of the ingredients in their blends and treat the formula's as proprietary trade secrets.

While the change to epoxy resin does make the tank less susceptible to problems associated with ethanol, because of other additives, it does not completely eliminate the problem. Based on my experience, I would still have a epoxy resin tank coated with some sort of epoxy sealant like Caswell sealant, but try to use race fuel if possible, and pump gas only when race gas is not available. And lastly, never leave any fuel in the tank for any extended time. While overnight may not hurt, I would not leave any fuel just sitting in the tank for more than a few days. I know that sounds like a bit of a pain, but it's the only way I know to extend the life of your expensive fiberglass or Carbon Fiber tank.

[gordo]

I was at an event this past weekend and another competitor saw me draining my tank at the end of the day. I have been doing this since I restored an old Ossa Explorer. He told me he uses aviation fuel and has had no problems with it in his Ossa. Lead content is 4 parts per million, no ethanol and 100 octane. Anyone else tried aviation fuel out there?

[swooshdave]

av gas works and so does racing gas.

just way more expensive and not quite as accessible for everyone.

[bulpedro]

I sealed my Alpina's tank with Caswell and painted it 5 years ago. I had zero problems with it until the summer of 2008. I'm in Maryland (MAVT area). That was when gas prices spiked. It was also when all of our pump gas finally had ethanol added to it. My tank started blistering. I've heard some say the ethanol eats the tanks and others say it won't. I just know what happened to my tank. After leaving gas in it for 4 years, I now drain all of the gas out every time I ride.

Pete

[barcota]

I sealed my Alpina's tank with Caswell and painted it 5 years ago. I had zero problems with it until the summer of 2008. I'm in Maryland (MAVT area). That was when gas prices spiked. It was also when all of our pump gas finally had ethanol added to it. My tank started blistering. I've heard some say the ethanol eats the tanks and others say it won't. I just know what happened to my tank. After leaving gas in it for 4 years, I now drain all of the gas out every time I ride.

Pete

Be very careful about making a blank statement about all gasoline having ethanol. I have done a lot of research on this subject when I started having a 5% reduction in fuel economy in my car when using known gasoline containing ethanol. Most gasolines in New York State do not contain ethanol. Here the pumps are labeled with the ethanol content (usually 10%, some 15%). Check with the local distributors in your area to find out which brands have it. I have had feedback from some trials riders that the ethanol ruins carburetor rubber seals and alloy fuel tanks on modern trials bikes. I would personally recommend that all trials bike owners do not use ethanol in their tanks (bikes or cars) - stick with regular pure gasoline or aviation gas. It will save you a lot of future problems.