Can anyone advise on a method to seal a fiberglass fuel tank.

Mine has split on the lower edge seam.

Would a epoxy resin be suitable.

Or can I just use the standard fiberglass resin / matt.

Thanks in advance

Hey DW,

There was a post about leaking takes a few weeks ago, and I think this covered repairing.

Might be of some interest...

Click Here

Standard fiberglass resin and repair procedures should be fine.

What bike has a glass tank?

The bike is a Cagiva DG350.

Is there not a sealer that i can use inside the tank,

after the external crack is repaired.

If i use fiberglass petrol would surely penetrate this.

I guess I am a little lost as to why the petrol will penetrate.

Here, there is a product available called Kreem (it can be seen on the web) not sure if it is available there or not. I believe it is also rated for Fiberglass tanks but I would have to verify that. My experience has been that at some point, it starts to cause more problems than it fixes.

A well done, multiple layer, properly faired in fiberglass patch, will restore a standard fiberglass tank to a like new condition, and if properly painted or gel coated, will be un noticable.

You could always take one of the two part epoxy putty sticks and gob it over the hole, and that would work, but not as well and would certainly be more noticable.

Depending on the split you may be able to grind out a small amount of the glass then repack it with milled fibre and resin. This would be neater than glassing over a larger area. Make sure you sand back any area you are going to putting new resin onto as the paint will not hold the new materials. Gelcoat will need to be sanded to allow the new resin to get a chemical bond.

On the inside of the tank ensure it is very clean and put some resin over the split area. Remember as resin goes off it generates heat so ensure the tank is as clean as you can get it so you don't have a fire. If there are raw fibres exposed to fluids the fluid will pass along the fibres.

Don't buy your products from a hardware store but go to a boat shop or better still a fibreglass trade centre and buy the correct resin etc.

If you decide to use tank sealer, contact aircraft supply places.

They'll sell you something that will probably say "Not for use in aircraft" on the can.

Insurance liability, y'know.

If you are going to the trouble of relining your fibreglass fuel tank, I suggest that you use low viscosity epoxy resin as the liner and buy it from an aircraft or boat repair supplier as previously suggested. The reason for this is that the automobile fuel or "gas" we buy will eventually contain ethanol if not already and polyester resin (which is what fibreglass fuel tanks are normally made of) is affected by ethanol.

I'm not actually advising relining with anything unless it is absolutely necessary because it adds weight and can be a bit tricky to get evenly spread inside.

Almost any fibreglass tank damage can be fixed by external repair if you take the advice already given on this string.

David Lahey

Australia