holed fibreglass tank

[keychange]

I was clearing a new practice track along a stream. Cota was parked out of the way - stand sunk in - bike fell over and hit a small tree stump. I think the universe is trying to tell me to find a new hobby.

[Jon V8]

You dont seem to be having the best of luck ! I managed to put a huge dent in the left side of the new alloy tank I put on my rigid AJS - second time I rode it.... The dent makes it look used but doesnt leak,so I'm not worried about it.How are your fibreglass repair skills ?

[David Lahey]

Fibreglass can be patched cheaply and easily. If you want the fancy, shiny red look again there will also be painting involved.

[bedouin]

Dead easy to repair that, a 4 inch angle grinder with a 'flapper disc' to sand the damaged are plus about 2 cm further to give a good base for the repair. any hardware store there days has woven glass matting and polyester resin in small amounts, more than you will need to do the job.

Try to sand the center piece to get a bond to it and make a small mix or resin and paint it on the tank out to the edge of the sanded area but not onto the painted(gel coated) part of the tank. Thrown that brush away and don't waste money cleaning it. Forgot to tell you get a half dozen really cheap and nasty brushes. Let the mix go off and then make a little bigger mix and cut a piece of glass cloth to fit right over the area and on a piece of cardboard completely wet it out, the matt will then look almost clear, place it over the area and tap the matt out with the paint bristles to work the matt into the resin and try to leave a flat surface as best you can. The resin will go off (harden) faster with each layer of matt but adjust the hardener to give you about 15 to 20 minutes working time and that will vary with temperature but regardless mix the hardener well into the resin. Work up 5 layers of matt and make sure all the air bubbles are worked out as you do and give it overnight to dry right out.

An orbital sander is the first step to getting the profile back to as it was then change to coarse 'wet and dry' sanding paper then going finer as it gets close. Finishing with about 240 grit will give you a good finish, a spray can automotive undercoat/primer in grey or white from Super Cheap and see if there is an auto pressure pack of a matching paint, if there isn't then you might consider sanding the whole of the tank and a full paint job. Sand it till it is covered in a dull finish from the sanding all over it.

Old clothes, plenty of cardboard to work on don't run your fingers through your hair while doing the job.

[David Lahey]

clean the premix residue out of the tank before you start using resin

[Takhli44]

I think the universe is trying to tell me to find a new hobby.

I think the universe is trying to tell you to cut your stumps shorter More seriously, too bad about the bash on such a nice old bike.

[Joe Henderson]

Dear Keychange,

The main problem with old glassfibre tanks on two strokes is that the oil has seeped into the laminate, which is porous, it is actually the gelcoat that is the only thing keeping the fuel/oil mix inside the tank.

I have had great success using epoxy resins and glass mat on tank repairs for my two slimline Bultaco tanks.

The epoxy is more tolerant of the pre-mix oil that will remain no matter how much and with what you clean the tank out. ( I used very hot water and Motorex Moto Clean 900 - " Bloody hell, $99.00 for 5 litres?" - but it does work well. )

Epoxy is completely different to Polyester, but will reward care and thorougness both in preparation and application, it does take overnight in a warm place to cure, though.
Be guided by the shop you buy it from.

Regards,

Joe.

[paulm]

Nice work bedouin and Joe - a complete Masterclass in fibreglass repair work in two posts

Best regards

Paul Mac

[keychange]

I fitted an older tank used to be fine and bugger me if doesn't start to seep from a point about half way up the side

I am going to call on an expert to do the main repair - I just don't trust myself. Meanwhile I will try a tank liner on the older tank and see if that stops the seepage

I have 3 old bikes and none are rideable - in fact I have hardly spent 10 hours on a bike in the last 6 months - but I have spent probably 100 hours working on the bas@#%&s

[keychange]

Bedouin

I have decided to give it a try as i already have all the materials on hand.

When you say sand the centre piece do you mean the flap of fibreglass that was pushed in by the impact. Or should I cut that out and start with a neat hole?

Also the tank has been treated with KBS sealer. Will this effect the bond on the inner surface?