Hi

 Forum newbe here with hopefully a simple question, I'm not a newcomer to composites having owned fiberglass cars for 30 years but I could do with some advice

I've been rebuilding some old fiberglass doors for a hillclimb car i'm building. they were damaged when the car rolled a few years ago and I'm using them on a new one I'm building. I've had to make new window surrounds, repair where the hinges got ripped out etc and they are now structually repaired. Due to the various repair methods I would like to skin the outside surface with a thin layer of cloth and an epoxy resin to give a homogeneous outer layer, to hopefully stop the repairs 'showing thro' . What would people recommend for the cloth and the epoxy for this job?, bearing in mind minimum weight is a factor on a competition car. Also, after adding this skin, what would people recommend as the next layer to prepare it for paint?, spray filler?, gelcoat?, etc.

Cheers

Eric

If the doors are fibreglass I'd be tempted to use a surface tissue or a really fine / lightweight woven cloth and polyester.  I'm not entirely sure if this will stop the dreaded 'sink' but it will certainly help.  The best thing to do for weight would be to re-mould them and make fresh doors.  You have the plug which is most of the work.

I should add, flat it down and then spray with high build 2k

Thanks FLD, I know you are right about making new doors, but I've stupidily spent too long repairing these doors already, when I could have bought some new ones . I've also got a complete Reliant Scimitar body to sort out that has had the paint and gelcoat removed by an angle grinder some time ago, which will need a similar final treatment. I think the best way is like you suggest, fine cloth and polyester resin, but I was wondering if an epoxy would be more stable ?, there are so many types out there now.

Epoxies bond better but aren't usually UV stable.  If its a standard fibreglass door I'd just go with polyester as its cheap!

I don't envy you the job of sorting out the scimitar.