GRP Fuel Tanks and Ethanol in Petrol

joliette said:
Does anyone know if there is a way to treat GRP fuel tanks to protect them from the damage that can be caused by the ethanol present in petrol?
Click to expand...


I was reading recently about the effects of the ever increasing amount of ethanol in our fuels on GRP tanks. I'm going to wait and see.

I wonder if the tank sealing products sold by the like of Frost for the old car fraternity would be ok in a GRP tank.
 
burgundyben said:
I was reading recently about the effects of the ever increasing amount of ethanol in our fuels on GRP tanks. I'm going to wait and see.

I wonder if the tank sealing products sold by the like of Frost for the old car fraternity would be ok in a GRP tank.
Click to expand...

The automotive products - like the one supplied by Frost - are only good for metal tanks. Some of the products used for sealing Aircraft tanks may do the job. I'm awaiting replies from the manufacturers but was wondering if there's anyone out there that has already been through this?
 
joliette said:
The automotive products - like the one supplied by Frost - are only good for metal tanks. Some of the products used for sealing Aircraft tanks may do the job. I'm awaiting replies from the manufacturers but was wondering if there's anyone out there that has already been through this?
Click to expand...


I think its something that boat owners have not really cottoned onto yet, perhaps partly because its not clear how serious the issue is.

AFAIK the automotive products are epoxy based, so why they would be suitable for only metal tanks I dont know. A friend of mine has an enquirey in with one of the epoxy suppliers asking the same question, is epoxy resistant to ethanol exposure long term.
 
burgundyben said:
I think its something that boat owners have not really cottoned onto yet, perhaps partly because its not clear how serious the issue is.

AFAIK the automotive products are epoxy based, so why they would be suitable for only metal tanks I dont know. A friend of mine has an enquirey in with one of the epoxy suppliers asking the same question, is epoxy resistant to ethanol exposure long term.
Click to expand...

David Geer's Boat Mechanical Systems Handbook alerted me to the issue. His position is to avoid fibreglass petrol tanks in new construction and to be aware of the potential problem from ethanol in existing boats. (Is this why grp petrol tanks are not permitted on the Inland Waterways under the Boat Safety Scheme?) There are lots of petrol powered boats in service with grp tanks - once considered the top quality solution for petrol storage - so this is a big issue now that we have around 5% ethanol in UK petrol. I gather the stuff is also hydroscopic!

Having done some research over the past few days there's clearly a lot more to resins than the epoxy / polyester split of insanely sticky stuff that I was previously aware of! The product recommended from Caswell is a Phenol Novac which has different properties than other epoxies.

It would be good to crack this one as there doesn't seem to be a proven product for the marine market ... which ought to be an opportunity for someone?
 
Hmm. that's very interesting, and somewhat worrying...

I was aware that my GRP tank was petrol resistant [it's made 40 years so far without a problem] but the effects of weakening wouldn't be good - in my case the tank is not separate, but is an integral part of the boat - the tank bottom is the hull!

The good news is that it would appear that biofuel [mostly ethanol] has only been introduced quite recently into UK fuels, it is currently mandated at 3.75% and will reach concentrations of 5% in 2010. Therefore maybe we have a little time to find a solution

I would have thought a suitable epoxy barrier coat would be a good starting point, if such a thing exists? [Google seems to indicate a guaranteed product doesn't] therefore I'd be thinking of going to a flexible rubber tank liner, although, that is not without it's problems as ethanol is pretty aggressive as far as most NBR grades are concerned and a Viton or Aflas solution would be very expensive.

Bloody tree huggers, they have a lot to answer for... - it seems green fuels have more than a few drawbacks.
 
Yes, it is a big issue particularly as (according to the AA http://www.theaa.com/motoring_advice/news/biofuels.html) the fuel companies will be legally obliged to mix in 5% ethanol from 2010, and I guess that the percentage mix will only increase over time as automotive technology evolves. It's worrying that a reliable epoxy coating - to protect our grp tanks - may not yet exist, given the apparent failure of the Caswell product. However, I can see that much time and effort would need to be spent to prepare the internal tank surface of my 50 gallon tanks to give any coating the best chance of establishing a permanent bond. I haven't really considered flexible liners as my tanks are divided into 3 sections by internal baffles, so I'm not sure how liners would work but I'll look into this.

Having not yet decided on a petrol or diesel engine solution for my project this ethanol issue may be a deciding factor, as I really want to avoid the need to replace the tanks.

Details of my project can be found at http://www.facebook.com/#/group.php?gid=179427293999
 
Scarron said:
Hmm. that's very interesting, and somewhat worrying...

I was aware that my GRP tank was petrol resistant [it's made 40 years so far without a problem] but the effects of weakening wouldn't be good - in my case the tank is not separate, but is an integral part of the boat - the tank bottom is the hull!

The good news is that it would appear that biofuel [mostly ethanol] has only been introduced quite recently into UK fuels, it is currently mandated at 3.75% and will reach concentrations of 5% in 2010. Therefore maybe we have a little time to find a solution

I would have thought a suitable epoxy barrier coat would be a good starting point, if such a thing exists? [Google seems to indicate a guaranteed product doesn't] therefore I'd be thinking of going to a flexible rubber tank liner, although, that is not without it's problems as ethanol is pretty aggressive as far as most NBR grades are concerned and a Viton or Aflas solution would be very expensive.

Bloody tree huggers, they have a lot to answer for... - it seems green fuels have more than a few drawbacks.
Click to expand...

Looks like this could work: http://www.bridgeportchemical.com/docs/pdb/GA0027P-_PDB_.pdf

I'm going to see if I can buy some.
 
You must log in or register to reply here.

Share this page

Top