GRP Repairs

[Asterix]

I'm thinking ahead to the summer when I intend to fix a few cracks and replace some sections of GRP on my horsebox,then give it a coat of paint,does anyone have experience of this and can recommend fillers and paint?
Also any info on prepping and finishing would be helpful.
I've had a look around on the www and the products I looked at seemed to have a limited range of colours,but whatever I go with would need to do the cab as well,so can they be used on metal or would it require another type of paint and just get it colour matched?
Thanks for any info,Dave

 

[Wully]

I do quite a bit of fibreglass roofing same princebles as any job it’s all in the prep stuff we use might be a bit heavy duty but you get different grades of mat and resins. Have a look on here I use this company for supplies. Think what you’ll need is gel coat this company do a great range of colours. Glass fibre supplies, tools and accessories | Allscot Distributors

 

[trevskoda]

Gel coat or glass mat repairs are simple,just gouge out and fill covering with clear waxed plastic sheet etc,then remove next day rub down and polish.
If you do want to paint then either use two pack etch or epoxy first and finish with two pack polyurathane with a roller,any bubbles strike of with a dry brush.
Jutan clark or sigma are top paints which will not run easy,some folk like international but good as it is it tends to run.
Boat supply or industrial outlets will help with paints.
I had 12 of these we boats to do in one week at belfast ship yard.

 

[Asterix]

If you are fixing cracks, you need to make sure the cause of the cracks is fixed as well.

OK, if you backed into a post it's easy: don't do it again.

If they are stress cracks from vibration, don't just add mat, fill and gel: add a bit of reinforcement at the back to stop the vibration bringing the cracks back next year.

Some cracks run between weak points that have old fixings in them but the overall construction is sheet ply with sheet GRP over the top so not really any way of further reinforcing from behind. One large crack is probably from a horse kicking the inside ply,and other smaller areas look like surface delamination and aren't very deep.
It may be easier to just replace an entire sheet but I can't seem to find a supplier online,the existing material is 4mm but the only stuff I've seen isn't in that thickness.

 

[trevskoda]

Some cracks run between weak points that have old fixings in them but the overall construction is sheet ply with sheet GRP over the top so not really any way of further reinforcing from behind. One large crack is probably from a horse kicking the inside ply,and other smaller areas look like surface delamination and aren't very deep.
It may be easier to just replace an entire sheet but I can't seem to find a supplier online,the existing material is 4mm but the only stuff I've seen isn't in that thickness.

Most boat repair shops will knock you a panel up on a flat table,or you could do it easy.

 

[Asterix]

Most boat repair shops will knock you a panel up on a flat table,or you could do it easy.

It probably sounds easy,but as a full-timer I can't imagine knocking one up in a layby.