Fibreglass Weight

Hi,

I have some questions on fibreglass. 

Can anyone tell me how much a single layer of e-glass/polyester weighs per square metre?  And how thick one layer is?  Are two layers twice as thick?

How much would the same square metre weigh when faired with some sort of compound and then painted?

Thanks in advance.

 

Unfortunately its not as simple as that...

The fibre itself comes in many different grades, thicknesses, weaves etc, all of which affects the weight of the final layup... A single layer could be 80 grams per square metre fibre or it could be 400gsm...
Very roughly speaking a hand layup will be 50/50 glass resin, more glass, less resin for a competent experienced laminator.

Two layers of 200gsm is about as light as you would want to go for the outer skin of a foam sandwich boat unless its going to get very careful and special handling off the water, so that's about 800 grams per square metre. I imagine things like RS boats will be rather heavier to make them more customer proof. Faired will be a bit more, how much is enormously dependant on how good the laminating job is and thus how much filler (and resin in the filler) is required.

Thickness... Never paid it a lot of attention. I believe three layers of 300gsm unidirectional carbon is about a millimetre when well consolidated (eg shrink wrap/vacuum bag.

[Later]
It would probably help if you told use what you need the information for, then you could have someore practical information...

Edited by JimC

Whats the model? That sounds pretty well-built if you are talking model yachts.

For referance my 1m canter is 2 layers of 160gm (with an extra layer in some of the key areas) and balsa cored deck/bulkheads and that seems about right for my purposes (its a little soft in the flatter unsuported sections but pretty light) 

The 50/50 ratio is by weight and is a pretty good guide... but as jim says this can vary a bit depending on your laminating experiance.


Edited by Isis

200kg/m² foam is very high density, and just fairing and painting should be enough.
If it's a big model, then the foam is going to be VERY expensive! 

chopped strand mat /polyester is by weight 25/75 maybe 35/65 if you're careful.

woven stuff you can get 50/50 with hand wet layup.

vaccing with epoxy maybe 55/45.

pre-preg + autoclave  ( high pressure ) 65/35

Thickness guide for vaccing fine fabrics

100g/m² ~ 0.1mm
200g/m² ~ 0.2mm
etc

+ fairing and paint.

A carbon foam panel painted one side is ~ 2.0 kg/m²

Originally posted by I luv Wight A carbon foam panel painted one side is ~ 2.0 kg/m²

a wind-energy glass prepreg for the shell of a turbine blade can be that for a single ply of material.

Some of the glass laminates I've made recently have effectively been 14 ply unidirectional +-30° 310gsm/ply glass. pre-preg, vac bagged, oven, they've been coming out at 3.5-4.0mm- the thicker ones have funky stuff in them, so 3.5 is probably the most representative figure.