Discussion
Hi
I'm new in the game or repairing GRP.
I need to make a flat finish on some GRP I've mended.
I was thinking of sending the fibreglass and then use some filler to make a nice plane surface.
Is that a good idea? Can you get black filler?
Thank for your help
Jack
>> Edited by jack&mle on Tuesday 19th July 13:38
I'm new in the game or repairing GRP.
I need to make a flat finish on some GRP I've mended.
I was thinking of sending the fibreglass and then use some filler to make a nice plane surface.
Is that a good idea? Can you get black filler?
Thank for your help
Jack
>> Edited by jack&mle on Tuesday 19th July 13:38
Rather late reply, but here goes.
Would be useful to know what the damage was and how you've repaired it. Obviously you've used glass fibre, but you don't say if that's just mat or if you've used tissue on top.
Anyway, sanding down the glassfibre and using filler to smooth things out should be OK. Surform is useful for taking high spots off GRP prior to using sadnpaper/wet or dry if it's really lumpy.
You should always wear a mask when sanding GRP/filler as it's not good for the lungs.
You might also find problems with cracks in the gel coat reappearing if you haven't ground them all out.
As far as I know you can't get black body filler.
Would be useful to know what the damage was and how you've repaired it. Obviously you've used glass fibre, but you don't say if that's just mat or if you've used tissue on top.
Anyway, sanding down the glassfibre and using filler to smooth things out should be OK. Surform is useful for taking high spots off GRP prior to using sadnpaper/wet or dry if it's really lumpy.
You should always wear a mask when sanding GRP/filler as it's not good for the lungs.
You might also find problems with cracks in the gel coat reappearing if you haven't ground them all out.
As far as I know you can't get black body filler.
grahambell said:
Rather late reply, but here goes.
Would be useful to know what the damage was and how you've repaired it. Obviously you've used glass fibre, but you don't say if that's just mat or if you've used tissue on top.
While in France, the boot release mechanism has decided to fall apart.
I had to break some fibre glass to open it.
I've repaired the hole as best as could with the stuff you can get from Halford.
I needed to have a flat surface to fit the new lock mechanism.
I will try later with some filler to make a plane surface which I will paint in black
Jack
I take it that's on the Caterham. Bad luck.
Best to use a sanding block when rubbing down to ensure you get a flat surface. Also, spray the repaired area with primer/filler and block sand that wet around 600 wet and dry paper to smooth of prior to top coat.
In fact best if you apply very light coat of black over the primer/filler to act as guide coat before rubbing down.
That way, when you block sand it, any pits or low points will show up as black and can be gone over with more primer/filler.
When you block sand the guide coat down and all you can see is smooth primer, you'll have a really flat, smooth surface to apply the top coat to.
Best to use a sanding block when rubbing down to ensure you get a flat surface. Also, spray the repaired area with primer/filler and block sand that wet around 600 wet and dry paper to smooth of prior to top coat.
In fact best if you apply very light coat of black over the primer/filler to act as guide coat before rubbing down.
That way, when you block sand it, any pits or low points will show up as black and can be gone over with more primer/filler.
When you block sand the guide coat down and all you can see is smooth primer, you'll have a really flat, smooth surface to apply the top coat to.
I'm doing a lot of work on my TVR prepping it for a respray. You have to make sure your repair is sound otherwise the results will look very bad. The rules are simple but need to be applied in all cases.
1. Make sure work area is washed clean and free of grease and dust.
2. Rub down repair area with 240 grade wet and dry to eliminate paint around the repair are.
3. Cut back with a sander/grinder where the damage is before laying up a coat of tissue and resin making sure the cracked area has been covered over.
4. Allow resin to touch dry before keying with some dry paper - fill over repaired area flatten with 60 grade dry until shape has been acheieved - u must always use a block.
5 start wet flatting with 240 then gradually changing to 400 then 600 before priming
6. Prime area...allow to dry fill any scratches or imperfections with stopper flatten again before priming.
7. Allow primer to go fully hard before flatting again then prime area again flatten with 600 before applying top coat.
When flatting the area prior to priming use a block and clean water with a bit of detergent.
1. Make sure work area is washed clean and free of grease and dust.
2. Rub down repair area with 240 grade wet and dry to eliminate paint around the repair are.
3. Cut back with a sander/grinder where the damage is before laying up a coat of tissue and resin making sure the cracked area has been covered over.
4. Allow resin to touch dry before keying with some dry paper - fill over repaired area flatten with 60 grade dry until shape has been acheieved - u must always use a block.
5 start wet flatting with 240 then gradually changing to 400 then 600 before priming
6. Prime area...allow to dry fill any scratches or imperfections with stopper flatten again before priming.
7. Allow primer to go fully hard before flatting again then prime area again flatten with 600 before applying top coat.
When flatting the area prior to priming use a block and clean water with a bit of detergent.
I'll have to dissagree with Andy, I've worked in a fair few bodyshops and I've never seen repairs done like that
IMHO
Do not use water, anywhere, not even to clean it before you start. You do use a lot of water to flat the primer before the top coat (or base coat if it's metalic) but that's AFTER it's been primed. The water can get into the matting, not good
>> Glass repair, will depend on area but ensure you've ground out all the area where the glass has de-laminated, I'd use mat with a sinlgle layer of tissue on top. No need for a key between layers IMO
>> You don't need to flat filler with 600 grade before priming. After getting it the right shape (40/60 grade) skim a very fine layer of top stop (fine polyester filler and sand that off with 120-240 (DA if you have one)) use a high solid primer directly on that
See the Chimaera link in my profile
>> Edited by Incorrigible on Wednesday 10th August 15:34
>> Edited by Incorrigible on Wednesday 10th August 15:39
IMHO
Do not use water, anywhere, not even to clean it before you start. You do use a lot of water to flat the primer before the top coat (or base coat if it's metalic) but that's AFTER it's been primed. The water can get into the matting, not good
>> Glass repair, will depend on area but ensure you've ground out all the area where the glass has de-laminated, I'd use mat with a sinlgle layer of tissue on top. No need for a key between layers IMO
>> You don't need to flat filler with 600 grade before priming. After getting it the right shape (40/60 grade) skim a very fine layer of top stop (fine polyester filler and sand that off with 120-240 (DA if you have one)) use a high solid primer directly on that
See the Chimaera link in my profile
>> Edited by Incorrigible on Wednesday 10th August 15:34
>> Edited by Incorrigible on Wednesday 10th August 15:39
Cheers Jack
No-where near Oxford I'm afraid, I'm in Sussex
When I fitted my headlight units, I bolted the unit to the existing glass (obviously I cut out a step in the glass to ensure the top surface was flush) This held them steady while the glass dried (I used P40 glass to glue them and then covered either side with a layer of mat before a top coat of filler)
No-where near Oxford I'm afraid, I'm in Sussex
When I fitted my headlight units, I bolted the unit to the existing glass (obviously I cut out a step in the glass to ensure the top surface was flush) This held them steady while the glass dried (I used P40 glass to glue them and then covered either side with a layer of mat before a top coat of filler)
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