I have never done any bodywork before. I've had to cut out the old bonnet bulge to let my engine out and the hole left behind is too large. I'd like to fill in the areas I've shaded blue, but I have no idea as to how I should approach this. Should I turn my bonnet over, glass fibre in some aluminium mesh from below and then build up on top of that? What is the best technique/materials to do this?



Regards,
Dave

I would go that route. Use the aluminium mesh bonded to the bonnet with GRP then layer on top once cured and fill with metal putty (not sure that normal filler will handle the vibration/flexing)

That's what I would do anyhow, but someone with much more nouse than me will be along soon I'm sure

HTH

JB

If you can form some alloy sheet onto the top surface and secure with self tappers etc. then prepare well with release agents you could simply build up gel coat and a few layers, with the last couple of layers overlapping the existing bonnet material.

Masking tape a piece of thin aluminium on the out side of the bonnet then fiber glass from the inside of the bonnet
using resin and matting after that rub down the out side fill with body filler and paint
Or fit a BIG scoop

From my experience of GRP as Jacko ^ says fit a big scoop which covers the whole area.
The problem you'll have is matching the gel coat colour of the surrounding, original GRP to your repair unless you intend spraying the whole lot?
TBH I'd think a big ass scoop will look better than having the plenium out in the fresh air.

If you are going to repair I'd ali plate a slightly oversize piece from the under-side, pop rivetting it on from the top by countersinking the rivet heads.
Then glass both top and bottom surfaces.
That way there should be little to no risk of flexing/crazing in the future.

HTH.
Cheers, Pewe10

The car was painted green, the original fibreglass is blue. I'm not after concours levels of finish, if it is approximately the right colour I'll be happy for now. The whole body is a bit tatty so I'll probably get a complete respray next year but for now I just want to reduce the size of the hole.
I did toy with the idea of a scoop, but I didn't find anything nearly big enough and I quite like the idea that the engine is too big for the car If I make a complete pigs ear of it I can look into scooping it later.

I,d stretch cling film over the area as fibreglass will not stick to it, then duck tape over the top to secure, flip over and back fill with fibreglass leaving plenty over so I could cut back.

Nice rough edge required for adhesion.

Leaving that lump sticking out the bonnet would annoy me, if I still had the original hump would carefully locate with some spacers for clearance then build up the sides.

Regards Mark

[Edited on 31/10/13 by mark chandler]

Tape some thin acrylic sheet to the bonnet where you want to fill then turn it over and resin and mat it from the back. Let the the new stuff cure then peel the acrylic off, cut to shape, fill and paint it. You could use anything flexible on top and put a sheet of cling film under it to stop it sticking then peel it off, I've done it a few times and it leaves a decent surface to fill on top of.

Dickie B has a mould I took for a bulge that should fit over that engine….

Well that was an interesting experiment in bodging; my fibreglassing is worse than my welding. I started off by covering the hole in clingfilm and then backing that with some cardboard

I got a fibreglass kit from my local motor factors (Milehams in Harpenden & Dunstable, top shop) and set about making a mess

The brake cable was the line I sort of wanted to keep.

I built up about 3 layers and realised that this is quite tricky to do well. Oodles of air bubbles that I just couldn't shift. Anyway, once it had all gone off, I flipped it over and did the reveal. What it revealed was the clingfilm I used was crap. The resin had permeated through it and soaked into the cardboard After I got that mess off I found that I hadn't poked the CSM in enough and there were some gaps between it and the bonnet edge
.
I'm now working on the basis that filler can hide a multitude of sins. If it works, it works, if it doesn't I'll just cut it all out and start again. I'm certainly learning new things anyway.

Regards,
Dave