I've chopped my scuttle in half and screwed it to a piece of wood spacing it out to the extra width so it fits the wider chassis I have. Now I need to build up the gap usiing fibreglass but would be grateful if anyone can let me know what I will need to do the job. Looked on here but too much choice!!

I'm not too worried about gel coat etc as I'm going to be filling/painting it anyhow.

I will also be doing the same to the FG dash I have for it too.

Cheers,
JB

If it were me...

I would screw the wood etc to the outside of the scuttle and fit a ply/clingfilm base on the outside following the contours of the body as close as possible...

Then lay up Chopped strand mat (CSM) with PU resin over the ply/clingfilm... keep laying it up in the gap.. once its deep enough, then start laying itup over the rest of the area around to form a nice big bridge over the gap.

If you think stifness is an issue.. get some nylon rope, soak it in the resin, lay it over the top and then put some more CSM over the top to bed the rope in..

Once it all sets, turn it the right way up, peel off the ply/clingfilm and then sand/fill/paint

I suggest CFNSET for supplies... just watch out for their postage fees!

I did a how too a while back on this -

linky

well for wings...same thing though

you'll need about 1m square of chopped strand mat and 1ltr of resin, couple of very stiff cheap brushes and the tube of hardener. Stuff sets in 30mins so work fast and have everything at hand. A standard fastglass kit will contain it all, which was what was used on the wings.

wear gloves






[Edited on 4/6/09 by Mr Whippy]

Whipy have you ever used the fastglas stuff?

I tried it in the past and the quality of the resin and matting was poor....

I got a MUCH better finish with the more expensive commercial stuff from CFSNET.... The resin seems to harden to a better solid for a start

Thanks for the replies chaps

What matting is best to use, i.e. 300gm, 450gm or 600gm?

JB

If you are going to get a couple of meters off a roll.. I would go for 300GSM...

Its easier to wet out each layer before adding the next... and if you have any bits left over you can use them for making small stuff afterwards...

I used 6 layers of 300gsm to fill in the sunroof hole in the roof...... and then filler to finish it off.... I could stand on that if I really wanted to!


Dont even bother trying to clean the brushes with anything.... it just makes a mess... I found the CFS budget brushes to be perfect for single use and then bin.... much cleaner and quicker

[Edited on 4/6/09 by tegwin]

Cheers chap

tbh I use the fastglass stuff quite a lot on model planes and general repairs. Can't say I've had any issues with it. The resin is a bit more brittle than epoxy but that’s to be expected. You do need a stiff brush to really wet the cloth and I tend to cut the mat up now into small squares about 4inches a side. I do that first and put them in a tub placing them in once the last square has been wetted out. Also prevents me having a half wetted mat if the resin goes off early. I always wear latex gloves when doing this, the resin is terrible to remove off your hands.

I'd agree the brushes are a waste of time trying to clean, never seem to get the stuff out off it even using the propper thinner. Just use a new brush.

[Edited on 4/6/09 by Mr Whippy]

I used the fastglass stuff a few times too, matting and resin was fine - especially for how easy to get hold of it is. The only thing thats ever gone wrong with it for me was once the hardener tube split as I was mixing the resin so I had about 5 minutes rather than 30 to work in.

As for the scuttle, put some matting and resin on from above, then remove the ply and do from the bottom too. Use isopon p40 to do the majority of filling and then p38 for a smooth top. If you're worried about stability of it then bond in an aluminium strip.

Don't think I'm too worried about stability as the dash will give it a fair amount of suupport too, (although I am widening that as well ), but it will be at around 90deg to the scuttle so should be OK, plus I will be bracing up the front with the firewall anyhow.

A far easier method than the wood / cling film idea is to fit a piece of ally sheet to the contours of the job , and rivit it in place .
Then turn it over , apply a generous coat of gelcoat to the `gap` , followed by a few layers of CSM , finishing with a good overlap each side .
The ally will just peel off , and being a gelcoat finish it will be easy to blend in , and shouldnt crack at the joins .
My experience of clingfilm is that it will wrinkle badly as soon as it see's resin , and will be next to impossible to separate from the fibreglass .

Lots of tips above, but just to add my own 2p:

Where Whippy above says that he cuts 4" squares to make it easier to place etc - Instead of cutting RIP THE FG BY HAND - that way when you lay it over each other you have nice overlaps of uniform thickness rather than cut lines that are proud.

(this isn't a critique at whippy, just a bit better process!)

ATB

Blimey! Loads of good advice there guys

I've just ordered some CSM and some resin, should have ordered some gelcoat too

I think I'll go with the gelcoat option as I would hate to have it all cracking at the joint later on.

Thanks again all, yet again the site delivers

Do check that "widen rear arches" thread that Mr. Whippy did a while back. I used wide cellotape around the contour and put thin strips of matte in there with resin. It looked very good when done actually. Here is a pic:

http://picasaweb.google.com/lh/photo/gphlyTQdcyqFp_CSUcmFzg?authkey=Gv1sRgCLfsoZrNyoKG4QE&feat=directlink

http://picasaweb.google.com/lh/photo/LAos3MfSBs-NGyfliRy_Ew?authkey=Gv1sRgCLfsoZrNyoKG4QE&feat=directlink

http://picasaweb.google.com/lh/photo/u78wAEbHftDKmScGwaZF2A?authkey=Gv1sRgCLfsoZrNyoKG4QE&feat=directlink

If you can get hold of it you can use acetate film (used on overhead projectors for presentations) which is stiffer than clingfilm and will not wrinkle but will really only follow a single contour. Or wide brown packing tape.