Mysterious Cracking to Fibreglass

[peebee]

I've noticed over the weekend that a strange crack has appeared on the inner edge of the wing, where perhaps the bonnet has rubbed as it closes. This wasn't there a week ago. I am concerned that it will spread!

See pics below:

Can this be dealt with by filling with standard car filler (is it P38 or something similar?) and should I drill out holes at each end to prevent further cracking?

Just when you think you've sorted out one problem along comes another!

[Rum Runner]

It looks more like a void in the layup process (air pocket)which usually happens on corners if the GRP mat is not pushed all the way in and fully wetted out with resin. The best thing to do is use epoxy resin and some microfibers or micro balloons .You can buy these in small kit complete from a yacht chandlers . Once this is used it will be stronger than the surrounding material. Just make sure the fill is not proud as it is much harder than the surrounding polyester based resin and glass so is a nightmare to sand.Once most of the hole is filled with epoxy and cured use a light skim of easy sand filler for final prep for paint. www.mailspeedmarine.com/ProductDetails/mcs/productID/107167/groupID/15/categoryID/151/v/ba556230-4ebb-4fb0-82ea-c7fa8e7ef103

Edited by Rum Runner on Monday 21st May 10:08

[hiltonig]

Yes i have some small cracks as well !, is it caused by the way the car is stored or is this just what happens with fiberglass bodies ???

[peebee]

Rum Runner said:

The best thing to do is use epoxy resin and some microfibers or micro balloons .You can buy these in small kit complete from a yacht chandlers .

Thanks Rum Runner, I have a fibreglass repair kit from Halfords which includes polyester resin and glass matting. Is the polyester resin the same as epoxy resin? The matting is quite big but I think I could cut it up and use just a few strands.

If I do this should I drill out round holes at each end to stop the crack lengthening, or will the repair deal with this?

Edited by peebee on Tuesday 22 May 09:13

[Rum Runner]

No polyester is much weekender to use if you have to go down the halfords road is to fill with P40 , its polyester resin paste with fibre glass strands ( less chance of running all over the rest of the lower paintwork), much easier to use than mat then over fill will P38 .The problem with most of the kits probably like the one you have got there is usually no powders to thicken the resin into a filler paste so it will not run out . With epoxy resin kits they come with powders so you can mix to desired thickness. Mix it and if it does not try to run off your mixing stick then its o.k. Because epoxy is so strong you can bridge big gaps with resin mixed with with powders to make the thick paste without having to use mat. I would imagine there is a decent sized void behind the gel coat/paint. Its a common problem with boats.

Edited by Rum Runner on Tuesday 22 May 15:20