I've found that I've got some serious scuttle flex when I switch on the windscreen wipers!!!! I'm going to re-inforce the underside of the scuttle with some bi-directional matt but my question is this- can you glassfibre upside down? If I try applying the bi to the underside will it stick or simply fall off?

Plan B is to detach the windscreen, mirrors, scuttle ali section, scuttle etc etc then flip over the scuttle and do the glassfibre work that way.... Might take a while though......

Also- anyone know of a good online tutorial to repairing gelcoat? I accidentally drilled one of the wiperbox holes in the wrong place!!! I've got some gelcoat pigment of the correct colour and clear gelcoat but how do I work out what % pigment I need (or does it not make much difference in practice?!?!)... I might resort to make up some gelcoat and gradually adding in pigment and making little chips of it to see which %age comes closest.....

Oh no!

In my experience if you are free-forming you will have problems laying up upside down. The saturated cloth is quite heavy and will want to stick, and might do in places, but will sag in the middle and leave you with little pockets and things.

The other option is to try and use something to push it up while it hardens - a vacuum bag woul dbe ideal but if its the udnerside of a scuttle I cant think that it would work. If you could get some polythene and some old cloth or something to pad out the polythene with, could you make a sort of plug which you could prop up under the cloth while it sets?

Maybe someone who's a GRP whizz will suggest something 10x easier!?

Am no GPS expert but can offer an alternative.

I used alu profiles and copious amounts of sikaflex to strengthen some weak areas.

Born out of having no gps supplies in house and it being a sunday. Worked a treat actually.

If you can form an alu plate or strip and incorporate the holes for the wipers you should be able to create a light but very stiff structure. Try to have a minimum of 2 to 3 mm of kit to handle differences in heat expansion.

the aluminum/gluey stuff sounds like it would be the quicker/asier option.

If you use ali strip with a right angle bend, that increses it stiffness a lot and depending on the tichness/size of the strip, it can still be bent into shape.

I used this methot, albeit held on with gluey stuff and small bolt to stiffen my bonnet.

Sounds like that might be a better option!!!! Especially as my last go at laminating some polyester resin glassfibre had the neighbouring garage owners coming over to complain about the pong!!!

You would be better taking it off if you are going to use GRP. If you want to make it stiffer you can make up some foam stiffeners.

make a toblerone shape out of foam and laminate this in place, will be much stiffer than just adding mat. Works better, looks neater if you smooth over the top edge. The glass matt wont go ever tight edges well.

You can even use a paper rope. Just twist paper into a rope. Not as pretty looking though.

For the chip, I dont know what pigment you have but for the normal stuff, 0.5 kilos of pigment will make a gallon of coloured gel.

If you only want a small amout just add a small amount of pigment to the amount of gel you need and mix. It wont take much.

Before you fill in make sure you have ground out the cracks so they dont continue after the repair.

Gel coat wont go hard in air.
You can either mix in a wax solution to make it set in air or tape some plastic over the area so the gell will set.

If youwant technical advice re limitations of grp etc speak to these guys

http://www.ecfibreglasssupplies.co.uk/store/

been very helpful inthe past and quality / service and prices are all excellent, ntdwm except a satisfied customer
atb
Mike

Okay cheers- thanks for the info re wax etc. I was wondering what the difference between gelcoat and flocoat was!!!

Where my mirrors mount was flexing so I glued some 16g aluminium plate on with body filler and that cured it.