ethanol petrol v GRP tank

[Freebee]

I have a grp petrol tank that is built into the boat and the hull moulding forms the bottom of the tank. on inspection today some grp parts inside the tank have the consistency of cheese presumably as the ethanol eats the resin.

Has anybody had any actual success with sealants or barrier coatings that they can recommend???

 

[thinwater]

I have a grp petrol tank that is built into the boat and the hull moulding forms the bottom of the tank. on inspection today some grp parts inside the tank have the consistency of cheese presumably as the ethanol eats the resin.

Has anybody had any actual success with sealants or barrier coatings that they can recommend???

I spent years in the petrol industry in the US, where we got ethanol 25 years ago and more of it. This was a common problem during the change over. The problem is that the petrol has permetated the tank and nothing will stick to it, no matter how far you grind. Worse, the damage is structural. I'm sorry to say this, but the tank is toast.

How old is the boat? Perhaps the healthiest way to look at it is that if had been a metal tank it would have holes by now. Replacement GRP tanks use ethanol-proof resins that are well proven.

While you are at it, replace all of the hoses and rubber parts on the engine and in the fuel system. The tank is NOT your only problem.

Blame agribusiness. That is the real reason.

 

[rotrax]

Motorcycle GRP tanks suffered from this.

A product called "Petseal" would usually fix it.

Trouble is, if the tank is a built in one, you will not be able to follow the instructions, which went something like " pour the Petseal into the tank and swill it around inside so as to cover ALL the internal surfaces."

How much does your boat weigh?

 

[macd]

I've experience of using ethanol-tolerant coatings in motorcycle tanks but, for the reasons Rotrax cites, they're simply not practicable in a built-in boat tank. But from your "consistency of cheese" description, it sounds way beyond that sort of remedial action, anyway.

 

[thinwater]

I'm not ordinary melodramatic, but if a bike tanks leaks, you step off. If a boat tank leaks, fumes collect in the bilge and you all die.

The tank is toast. Do it right.

 

[Freebee]

Thanks to all- I think the tank has to be replaced now simplest solution would be to lay a bladder in the old tank but I need to find out if they are ethanol resistant.