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-   -   Fibreglassing Tips & Tricks (https://madabout-kitcars.com/forum/showthread.php?t=7314)

Bellicose 25th June 2020 09:35

Fibreglassing Tips & Tricks
 
Hello beautiful people!

I'd like some help and advice on my first outing into using fibreglass.

My Bellicose project has stalled and I think I can kick start it and work quicker with fibreglass.

My plan is this.

Finish the rough shape with the expanding foam as I have been.
Cover the car in parcel tape (as resin shouldn't bond to it).
Fibreglass the car with two layers 300gsm + two layers 450gsm + two layers 300gsm + one layer tissue + one flow coat of resin.

Put filler where needed.

Sand like mad, then spray primer filler a few times and sand like mad again.

Wet sand to lovelyness.

Then be ready to take a mould off my lovely new car.


Firstly does that sound like the right thing to do? Can anyone see any massively gaping holes in my plan?

Secondly does anyone have any tips to help me along my way as I've never used fibreglass before (properly in anger).

kon 25th June 2020 12:22

I'm not sure if you'll need that much glass on your buck. I dont think it needs to be as strong as the parts you make from the mold, as it's only there to keep the right shape, isnt it? 2 layers of 300gsm+tissue+flow coat should be good enough to take a mold, as far as I can tell, but I've not actually made a buck myself yet.
Other than that, sounds good to me.
I'm planning on a lazier option myself; chicken-wire + padding + poly sheet for the "buck". create surface layer of glass, remove from buck and then fill in behind to re-inforce the shape and create mounting points. I'm not sure what problems this will create, but the way you mention is i believe the more proper way to create FG panels.

Bellicose 25th June 2020 13:09

Thanks Kon, reason to make it thicker was I can use that as an actual body afterwards (once foam is removed form inside)

NeilF355 25th June 2020 14:36

Quote:

Originally Posted by Bellicose (Post 104609)
Cover the car in parcel tape (as resin shouldn't bond to it).

Hi
That sounds like a lot of parcel tape!

Any sort of acetate film should do to stop the resin sticking.
I have a roll of pallet shrink wrap that I use, good old clingfilm will do just as well.
If the film wont stretch over the car you might get a few creases in the surface but from your description that will be on the inside of the buck so it shouldn't matter.

Bellicose 25th June 2020 14:39

Quote:

Originally Posted by NeilF355 (Post 104614)
Hi
That sounds like a lot of parcel tape!

Any sort of acetate film should do to stop the resin sticking.
I have a roll of pallet shrink wrap that I use, good old clingfilm will do just as well.
If the film wont stretch over the car you might get a few creases in the surface but from your description that will be on the inside of the buck so it shouldn't matter.

Awesome tip! Thanks! :thumb:

Paul L 25th June 2020 17:40

Quote:

Originally Posted by Bellicose (Post 104609)
… Then be ready to take a mould off my lovely new car.

Quote:

Originally Posted by Bellicose (Post 104613)
… reason to make it thicker was I can use that as an actual body afterwards (once foam is removed from inside)

Bellicose – Please don’t think I’m nitpicking, but you appear to be describing two different things.

If you want to take a mould of the shape to make a new part, you are building what is called a ‘buck’.
In which case, the shape you create becomes the mould and you would build it in reverse.
See Mister Towed making a buck for his dash from Post #96 here:
http://www.madabout-kitcars.com/foru...?t=6672&page=5

But, if I’ve understood you correctly, you are actually building the final body shell shape.
In which case, the first thing to consider is how thick the final layers of matting and filler will be.
Because you will need to remove that distance from your foam shape before you start.
Otherwise, if your foam aligns with your ideal wheel arch distance, your final body shell will be wider.

https://live.staticflickr.com/65535/...cdd95242_b.jpg

The approach you are describing of fibreglass matting and filler is what I used to make my scuttle from scratch.

https://lh5.googleusercontent.com/-J...o/DSCF2895.JPG

https://lh3.googleusercontent.com/-I...o/DSCF3783.JPG

Here is an example of me using cling film over foam for my fibreglass bonnet bulge.

https://lh4.googleusercontent.com/-r...o/DSCF4680.JPG

https://lh6.googleusercontent.com/-w...o/DSCF4681.JPG

https://lh4.googleusercontent.com/-t...o/DSCF4682.JPG

I also used parcel tape on beer cans to male tail pipe cut outs.

https://lh3.googleusercontent.com/-w...o/DSCF3418.JPG

https://lh3.googleusercontent.com/-J...o/DSCF3426.JPG

Before I started my build, I’ve never used fibreglass before.

Unfortunately, I had a LOT of practise working with fibreglass during my build. :rolleyes:

The old saying is true, that the more you practise, the easier it gets.

Is there a small piece you could start on first?

If not, just make something up to practise on.

I posted my beginner’s approach to working with fibreglass here:
http://www.madabout-kitcars.com/foru...postcount=1132

There are several build threads on here that cover fibreglass worth that are well worth a read.

Good luck, Paul. :)

Bellicose 25th June 2020 17:47

Thanks Paul, I hadn't considered the extra cm the fibreglass would add on top of the finished foam!

rossnzwpi 26th June 2020 10:40

If you are using polystyrene foam to form the basis of your shape and want to apply fibreglass over it then the main problem is that polyester resin aggressively eats the foam. It isn't about creating a smooth release layer - its about keeping any drop of the liquid off the foam. You better have some very waterproof sealant there. The resin could well attack the glue on parcel tape too so do some test pieces with whatever you try. I've used cling film over a form made of plasticine with polyester and believe me the polyester resin somehow got through the clingfilm and the plasticine stunk to high heaven of resin.

Another option is to use a more expensive resin - epoxy. It does not chemically dissolve the polystyrene foam. However it is still exothermic so don't let a great big pool of it form or the heat might damage the foam.

Bellicose 26th June 2020 10:44

Thanks rossnzwpi, the tape was kinda for both release and foam protection, I might double up with tape and cling film for belt and braces!

Mitchelkitman 26th June 2020 11:11

If you use PIR (Polyisocyanurate?) foam the polyester resin will stick to it but won't attack it. Builders merchants Celotex or other make (tan coloured) sheets with silver foil on one side and paper on the other is a lot cheaper than most sources - just peel off the foil and paper (stinks when you do it :eusa_sick:). fit in place, carve to shape and cover with resin one coat of resin ('cos it soaks it up) then add resin/matting. Foam can be broken off after the GRP has set.

Bellicose 26th June 2020 11:45

There will be some need of flat pre made foam I think so will keep that in mind, thanks Mitchelkitman

Munky 11th July 2020 01:16

Not sure if you have stumbled across this, but I found this thread of someone else, who is 2 years into building a new kit on a 350Z platform pretty interesting.
https://www.madmechanics.com/forum/f...476095-falcata
It’s the guys first kit and shows some of the stumbles and wins along the way.
The kit isn’t really to my taste, but interesting nonetheless.

Then there’s Colins build on these very hallowed pages...
http://www.madabout-kitcars.com/foru...ead.php?t=6645

Bellicose 13th July 2020 09:33

Awesome links! That 350z build is not a million miles away from what I'm doing (only he is doing it better lol) Thanks Munky

On a side note I love your name, our gaming clan is called xBADxMunky

Munky 14th July 2020 00:21

Thank you.
Mine is from a Chinese / Japanese TV show I watched as a kid, when the BBC were on strike. Monkey Magic which stared the Monkey King. :)

Some of the guys on here make creating panels look so easy... Can’t say my adventures in that direction have ever been quite so successful.

Good luck with your kit and remember if you don’t at first succeed, try, try, try again (or pay through the nose to have someone else do it - which isn’t in my vernacular! I’m too tight!).


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