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How thick of a repair?

PostPosted: Mon Mar 09, 2020 5:59 pm
by tdskip
Good morning/afternoon gentlemen. Hope everybody had a good weekend.

I’m getting close to putting stuff back into the car, and I wanted to get some coaching on this trunk section. There was a perforation here where the fiberglass had cracked, I’ve repaired that but not sure if need to put more material down.

This was taken from the dark of the trunk with exterior lights on.

Any coaching to offer up?

Thanks!

CB1FCBB6-FB5D-4411-8026-569E9CD17051.jpeg and

Re: How thick of a repair?

PostPosted: Mon Mar 09, 2020 8:59 pm
by h20hamelan
I believe there is an inner and outer to the boot lid, and if it is going to affect, or have an effect on the paint. Then yes.
add lightness
carve out the crack, as glass fibre does not bend well past 30degree. and no need to go farther than 15% past width of crack with fibre, depending on length of crack and strength required etc
do not attempt to bond to anything but fibre. so make sure you see some white fibres after grinding/sanding

Re: How thick of a repair?

PostPosted: Tue Mar 10, 2020 11:17 am
by Andy8421
A good quality repair doesn't need to be any thicker than the original panel.

Don't worry about light shining through, the whole car lets light through without paint. There is a book by Miles Wilkins 'How to restore fibreglass bodywork' that details the technique for repair. A quick summary:

Clean all the paint / underseal off around the repair.
Grind approximately 2/3 through the panel at the split, shamfering this around the repair with the grinder to create a smooth transition.
Layup new resin / mat over the repair to the depth of the existing panel.
Wait for it to set, then do the same from the other side of the split, grinding into the new material as well as the existing panel.
If the panel needs a good finish, then use tissue mat as the final layer.

A diagram makes this all clear, but I couldn't find a link.

Edit: This is the book.

https://www.amazon.co.uk/Restore-Fibreglass-Bodywork-Osprey-Restoration/dp/0850455561

The companion book, 'How to restore paintwork' has been left behind by modern paint techniques, but the fibreglass book is well worth having.

Re: How thick of a repair?

PostPosted: Tue Mar 10, 2020 12:22 pm
by pharriso
h20hamelan wrote:I believe there is an inner and outer to the boot lid, and if it is going to affect, or have an effect on the paint. Then yes.


How did we get from "Trunk" to Boot lid?

Re: How thick of a repair?

PostPosted: Tue Mar 10, 2020 2:11 pm
by tdskip
Thanks for all of the responses and information. I very much appreciate the tips and techniques.

The repair is as thick as the original material and appears to be adequately strong so I am going to call this good for now.

I need to clean/scrub the whole trunk area still but then semi-gloss black paint in that whole area?

Thanks!

Re: How thick of a repair?

PostPosted: Tue Mar 10, 2020 3:45 pm
by alan.barker
pharriso wrote:
h20hamelan wrote:I believe there is an inner and outer to the boot lid, and if it is going to affect, or have an effect on the paint. Then yes.


How did we get from "Trunk" to Boot lid?

We started speaking English :mrgreen:
Alan

Re: How thick of a repair?

PostPosted: Tue Mar 10, 2020 3:58 pm
by h20hamelan
Looked like the top part of the boot lid.
Maybe it is in the boot, and some people attach a trunk to the rear of an automobile to carry things.
Either way, the picture is not very telling.

Re: How thick of a repair?

PostPosted: Tue Mar 10, 2020 6:09 pm
by tdskip
Sorry gentlemen, bottom of the boot on the passenger side.