Fibreglassing without gel coat?
coozer - 4/10/12 at 03:46 PM
I need to make some panels out of fibreglass to repair the body on my Jago..
Basically want to make a new bulkhead and floor with trans tunnel so not bothered what hey look like.
My plan was to lay up some sheets with out gelcoat so I could laminate some more on both sides once in place. Then cover the outside with flowcoat to
seal it up.
For the bulkhead was thinking of using a plywood former covered in the non stick plastic stuff and laying resin on and rolliing the mat onto it. Once
set laminate more layers on the inside, and the outside to get a good thick stiff result.
Is my plan OK to not use gelcoat? or, not going to work?
Never done any 'glassing before so be nice
tegwin - 4/10/12 at 03:50 PM
No need for gelcoat atall. I have used a large mirror/sheet of glass before with some wax based polish on it to create flat sheets.
designer - 4/10/12 at 03:57 PM
I always lay my sheets in melamine.
Confused but excited. - 4/10/12 at 08:11 PM
Definately don't need gel coat. I'm about to help a neighbour to cover his garage roof in f/glass (when the bloody weather lets us) just
using choped mat and resin. He's a boat builder.
Edited to put in the 't' I'd left out and you can't do a job without 't'.
[Edited on 4/10/12 by Confused but excited.]
ashg - 4/10/12 at 08:12 PM
have a watch of this. john is a bit of a legend with fibre glass, he is using carbon in this vid but the principle is identical.
http://www.openfilm.com/videos/ckc-workshop-stoneleigh-2011-carbon-laminating/
if you want his proper production dvd thats really good you can get it here.
http://www.basicfibreglasstechniques.co.uk/
coyoteboy - 4/10/12 at 09:26 PM
THe only issues ive had without gelcoat is having the surface remain tacky, indefinitely. Everyone tells you you dont need it and you don't if
you lay up against a surface but you can get unexpected results on the un-finished side. You can get styrene additive to help but it doesnt cure it in
my experience.
[that;s with polyester resin, with epoxy it's fine]
[Edited on 4/10/12 by coyoteboy]
Madinventions - 5/10/12 at 12:47 AM
That sounds pretty much like how I made my hard top...
I first made a former out of wood and polystyrene, and covered it in brown packing tape. I then covered this with a layer or two of matting, then
removed from the former. Inside, I used coremat to bulk out the thickness and this adds a lot of strength without too much added weight. Never had
any problem with the surface remaining tacky (polyester resin) but I painted it anyway to seal the outside surface.
I got most of my supplies from East Coast Fibreglass Supplies, and I would recommend getting plenty of resin and matting as you'll end up making
loads of things! I would also suggest that you get a "consolidating roller" which makes it very easy to get the matting down onto flat
areas quickly.
Ed.
MK9R - 5/10/12 at 06:43 AM
We make all our bodywork without gel coat, it saves loads of weight and as long as you roller it really well the finish is like glass. We have been
using the Easylam resin from CFS recently and getting soome great results with it, its not as gloopy as the normal resin so it penetrates better and
you dont use anywhere near as much.
Peteff - 5/10/12 at 08:15 AM
You can use fleece instead of matting and impregnate it with resin to get a shape, it's used a lot to make speaker pods and simplifies things a
lot. I have also used cling film wrapped round the buck as a release agent and it peels off after and doesn't leave too many wrinkles. You can
make different size rollers out of washers on a piece of coat hanger wire.
[Edited on 5/10/12 by Peteff]
Neville Jones - 5/10/12 at 09:34 AM
quote:
Originally posted by MK9R
We make all our bodywork without gel coat, it saves loads of weight and as long as you roller it really well the finish is like glass. We have been
using the Easylam resin from CFS recently and getting soome great results with it, its not as gloopy as the normal resin so it penetrates better and
you dont use anywhere near as much.
Be careful of the thinned resins, they get a lot more brittle with a lot less age. Using the Easylam may turn and bite your backside in short time. I
know from experience. The only thin resin is Scott Bader 272, and it costs.
[THe only issues ive had without gelcoat is having the surface remain tacky, indefinitely. Everyone tells you you dont need it and you don't if
you lay up against a surface but you can get unexpected results on the un-finished side. You can get styrene additive to help but it doesnt cure it in
my experience.]
The fix for this is wax solution.(Wax dissolved in styrene) Add a little to the resin, and the wax comes to the suface to seal it, and allows the
resin to harden on the surface.
Cheers,
Nev.
MK9R - 5/10/12 at 09:48 AM
Nev,
Do you mean the grp product will become brittle with age, or if we use the resin after its sat in storage for longer it will be britttle? If its the
products themselves I'm not worried about that as I usually destry them every few weeks 
coyoteboy - 5/10/12 at 11:35 AM
quote:
Originally posted by Neville Jones
The fix for this is wax solution.(Wax dissolved in styrene) Add a little to the resin, and the wax comes to the suface to seal it, and allows the
resin to harden on the surface.
Cheers,
Nev.
Yeah I tried that but it still didn't help, it just left a very fine waxy surface that had to be removed after . After a lot of research I found
that polyester resin doesn't cure fully in oxygen/air hence the need for the wax coating, but I tried 3 more times on 3 different boards and
still couldn't get a decent coating to cure and not go milky in water. The surface against a mould was fine of course. I should have persevered
but for small one-off jobs it just cheesed me off and cost me enough time to make it more worth while switching to epoxy resin which cured first time
every time like glass, with UV stabilisers etc. Not cheap for something the size of a car though!
Steve Hignett - 5/10/12 at 09:53 PM
to OP - Steve, I have a couple rolls of specific "slippy" plastic. Let me know if you want me to unroll you some of the material and post it
to you - I have plenty enough for my own projects, so you can have it free of charge, but because I'm totally skint (as normal) I would just ask
that you'd cover the postage if that's ok with you?
Let me know if you're interested via U2U, and if you leave your number again (new phone) I'll give you a call about how it works and any
general FG advice aswell if needed...
ATB
Steve