andrew-theasby
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| posted on 23/11/10 at 10:16 PM |
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coremat?
Hi, i have some flat fibre glass panels im wanting to stiffen up. I cant mould ribs on the back, i was just going to lay up another layer or 2 of csm
on the back until i came across coremat. From What ive read i can use this in the middle of the layers of csm to make it even stiffer for less weight
increase.
My question is can i use it on an already cured panel ie polyester resin on, coremat on, then csm, then roller it through? Or does it have to be all
layed up in one go to adhere to both sides?
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clairetoo
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| posted on 23/11/10 at 10:28 PM |
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I would give it a good clean with acetone , then a layer of CSM , coremat , then CSM .
Its cuz I is blond , innit
Claire xx
Will weld for food......
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austin man
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| posted on 23/11/10 at 11:00 PM |
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what about the stick on panels used to reduce vibration in doors etc
Life is like a bowl of fruit, funny how all the weird looking ones are left alone
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andrew-theasby
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| posted on 23/11/10 at 11:03 PM |
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Thanks Claire
Not seen the stick on stuff, any idea what its called to look it up?
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MikeRJ
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| posted on 23/11/10 at 11:09 PM |
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quote:
Originally posted by austin man
what about the stick on panels used to reduce vibration in doors etc
That doesn't add any stiffening though, it basically bitumen (or a lead/bitumen sandwich for the posh stuff) which provides a lot of damping to
acoustically deaden panels. It's very heavy as well.
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andrew-theasby
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| posted on 23/11/10 at 11:21 PM |
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Ah right, doesnt really sound like what im after then, ill give the core mat a try. Ta
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Madinventions
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| posted on 23/11/10 at 11:58 PM |
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I used this stuff Fibreglass Polyester 3mm Coremat XI Bulker Mat 3m x 1m on eBay (end time 17-Dec-10 15:59:30 GMT) for my
hard top that I'm currently working on. You'll need quite a lot of resin (it needs to be saturated), and a layer of CSM over the top but
it will stick to cured GRP if the surface is well cleaned with acetone.
Clean the surface
Apply a thick film of resin
Lay on the coremat
Saturate with resin
Lay on the CSM as normal
It makes a lot of difference to the stiffness of a panel! 
Ed.
Mojo build diary: http://www.madinventions.co.uk
Solo music project: Syrrenfor http://www.reverbnation.com/syrrenfor
View my band website:
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Steve Hignett
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| posted on 24/11/10 at 07:21 AM |
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Hi Andrew,
How much coremat do you need/want?
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Neville Jones
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| posted on 24/11/10 at 09:56 AM |
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quote:
Originally posted by Madinventions
I used this stuff Fibreglass Polyester 3mm Coremat XI Bulker Mat 3m x 1m on eBay (end time 17-Dec-10 15:59:30 GMT) for my
hard top that I'm currently working on. You'll need quite a lot of resin (it needs to be saturated)/, and a layer of CSM
over the top but it will stick to cured GRP if the surface is well cleaned with acetone.
Clean the surface
Apply a thick film of resin
Lay on the coremat
Saturate with resin
Lay on the CSM as normal
It makes a lot of difference to the stiffness of a panel!
Ed.
Trick is to thin the resin with styrene, this lets the Coremat saturate with less resin, and a lot easier. Also keeps weight down.
Thin foam would be a lot better, and less weight, but Coremat is a cheap(?) and cheerful halfway substitute.
Cheers,
Nev.
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twybrow
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| posted on 24/11/10 at 12:35 PM |
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It is good stuff, but as others have said, just be aware it soaks up resin like a sponge.... Remember also that the resulting laminate should be
symmetrical about the centre line, in terms of its layup... so if you add coremat now, you will need to also add everything currently below the
coremat above it... othersie it will warp considerably (shrinkage in the resin).
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CNHSS1
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| posted on 24/11/10 at 02:57 PM |
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best to add coremat into a moulding from day one as part of the layup, virtually no shrinkage then.
in this instance as the panel its to be added to is already cured, abrade and then wipe thoroughly with acetone as mentioned before.
as for resin loading, just because it can absorb large quantities of resin, doesnt mean you have to. On racer panels i always just use a paint roller
and qucikly and lightly run over both sides of the coremat (very sparingly, but even) before adding to the panel and then add a sparingly wetted out
layer of CSM or wove over the top. Try not to add resin to the additional layer of glass as the core will just absorb it, just work the pre-wetted
additional csm or wove with an ally roller. Trick is to get thin even coverage and use minimum amount of resin (heavy component)
if using the foam sheet (10-15mm thick) radius the edges, chamfer,so that the CSM or wove over the top drapes over it properly and doesnt leave a gap
as that affects the strength a fair bit and its always the blunt edges where the panel breaks in a shunt as it becomes a stress raiser.
"Racing is life, everything else, before or after, is just waiting"---Steve McQueen
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andrew-theasby
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| posted on 24/11/10 at 07:26 PM |
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Do you think shrinkage will cause me a problem, the panels are approx 1m wide x 35cm, i made them of 4x450g CSM and i was just going to add one more
layer till i came accross this stuff. Thought i could maybe have just added 1 layer of coremat then a layer of 300 g/sqm to make it stronger still.
If i need to add 4 layers its gona be way too heavy too. am i best just sticking to the original plan of 1 layer of csm? Thanks
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twybrow
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| posted on 25/11/10 at 12:58 PM |
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Probably stick to the original plan then, but it wont be anywhere near as stiff....
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