BenB
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| posted on 30/3/07 at 07:53 AM |
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Glassfibre stuff
Hi all!
After my rather chilly drive the other day I've decided it's finally time to fit the heater bits I've got sitting around in the
garage.... The oil coolers a funny shape so I'm going to cover it in a GRP cowl....
My question is this- which is stiffer / stronger better, 3 layers of 200gm GRP or 1 layer of 600gm GRP. I would have thought three thin layers but I
seem to recall a theory that one thick layer is better... Or is it that you really need GRP to be thick so it's better to have 2 layers of 200gm
with some coremat in between to give some depth...
Thanks for any advice- I've done CF work before but due to the cost we tended to work with what cloth we had available!!!
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twybrow
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| posted on 30/3/07 at 08:00 AM |
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You are right with your last point. Nominally the stiffness of the 3 x 200g would be the same as 1 x 600g. If hand layup is being used, I would choose
the 3 x 200g as you will ensure better wet out and consolidation. As you say to achieve stiffness you either want to seperate the layers with
something like Coremat, or put a layer of carbon in there.
[Edited on 30/3/07 by twybrow]
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Hammerhead
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| posted on 30/3/07 at 09:23 AM |
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how much cf would you need? might have some going spare.
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mookaloid
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| posted on 30/3/07 at 09:38 AM |
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Heater? you'll be fitting a radio and roof next
"That thing you're thinking - it wont be that."
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BenB
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| posted on 30/3/07 at 10:21 AM |
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quote:
Originally posted by Hammerhead
how much cf would you need? might have some going spare.
Its a fair bit to be honest- one of the reasons I'm going glass fibre(ie cost of that much carbon!)... 8 plates approx 20*20 (I'm making a
three part plenum for the heater matrix), then enough to cover the whole thing.... Carbon has always looked scarily expensive when I've thought
about buying it (that's why I normally just blag it off my brother but he's gone all pre-preg....)...
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BenB
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| posted on 30/3/07 at 10:34 AM |
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quote:
Originally posted by mookaloid
Heater? you'll be fitting a radio and roof next
LOL! Almost!!! Roof and an intercom system!!!
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twybrow
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| posted on 30/3/07 at 10:38 AM |
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Why not layup in glass, and cover in carbon for that true Halfrauds style!?
So you need around 6+m2 of carbon for your job? From a supplier that would be around £100+ depending on weave style and fibre specification. For
cheapness, you could use a larger tow fabric. The really pretty ones are the small tow fabrics, but they cost the earth. Try some supplier for some
'24k' woven material.
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BenB
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| posted on 30/3/07 at 11:35 AM |
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To be honest I'd be happy with GRP... It's true that CF can look very pimpy bling but its always a dilema when you do a simple lay-up on
top of a buck . Do you make the inside smooth and accept a fluffy outer layer (which is never going to look that bling) or have a smooth shiny outer
but nasty stuff internally? I made my airbox out of Carbon (polystyrene carved and sanded, CF on the outside then petrol to dissolve the styrene)-
smooth on the inside but loads of strands visable etc on the outside. I ended up spraying it silver anyway, so GRP's no real problem....
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Hammerhead
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| posted on 30/3/07 at 12:33 PM |
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if you are wet laying up over a mould you can use 'peel ply' to get a flat matt finish. Then if you want shiny you could spray plasticote
laquer on it maybe.
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BenB
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| posted on 30/3/07 at 01:56 PM |
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True.... Then again, check the interior of my car!! It sure ain't built to be pretty  Bling ain't my thing!!!! Good plan though...
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twybrow
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| posted on 5/4/07 at 01:41 PM |
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Peel ply gives a horrid finish! If you want a smooth finish, build up your plug however you want (chicken wire and paper-mache works well. Then skim
everything with body filler. Sand back to the shape you want, and spray with a decent primer. For a box, do it the same as you did (with polystyrene)
and drill a small hole to pour in your solvent. The thin layer of filler should come out pretty easy afterwards...
I am using some very fancy stuff at work at the moment - it can be cast and then dissolved using water!
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