My second hand fury bonnet has a massive bulge in it that I want to reduce, I also need to cut out some heavy bits where it has been crash repaired in the past.

To reduce the bonnet bulge I will simple cut out the lump, knock out some formers in MDF to create a new profile then glass on top using cling film so I can easily seperate ( i have no interest in making a buck so may steal the profile from a car bonnet and drop on top) so:

how do I get a smooth finish on top of the matting? Or is it just a case of filling and sanding flat?

Where the new joins the old how do I get a decent bond? Just scratch the edges up and stick on top or do I need to sandwich the old between the new so build up both sides and maybe add a few holes along the old edge of the old for a mechanical join.

Cheers Mark

This is an area in which I have a specific interest. Will have to do some glassfibre recon work, plus adding a new bonnet bulge, so I'll be very interested to read any informative feedback.

Hi Mark. Final finish will be down to filling and sanding etc.

Joining / repairing holes is best done with a shallow taper giving a large bonding surface.
I have seen an excellent demonstration video from the States showing the repair of a hole. The hole was sanded so that there
was the maximum surface available in plan view for new glass to bond to. Lots of layers starting with ( I think the small ) pieces
finishing up with the large pieces - if you know what I mean. Final coat was then sanded, filled, sanded and painted.

Len.

Thanks Len, it looks like a lot of work required then.

Use surface tissue for upper most layer of mat, then light skim with sandable body filler.Not too difficult providing bonnet bulge is a simple shape, and shouldn't need to much sanding. Try not to use too much resin as tends to distort slightly as cures, and roller well to eliminate any possibility of air bubbles.

Thanks minibull, some tissue and a roller ordered