Carbon Fiber Resin Infusion - How many layers?

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#1

Hi everyone.

If you’ve read my previous posts you have probably guessed im looking at making motorcycle fairings using resin infusion.

Is there a guide or anything to give you an indication on how many layers of carbon to use depending on the size of the part? Iv tried searching google but I cant really find any helpful info.

For example, im using 200gsm plain weave carbon fiber, non of them carry any sort of load just the weight of themselves. How many layers will I need if my parts are roughly 1sqm, 0.5sqm & 0.25sqm?

Is there anything I can do to reduce the number of layers but keep the part strong? Example if 3 layers are needed, what can I do to it to reduce it to 2 layers but keep the same strength or very close?

Thanks

#2

Carbon fiber composites are quite strong and even two layer composites can handle quite a load in tension. However since they’re so thin they bend and buckle easily.

For cosmetic or parts that are lightly loaded you can include a core to keep the bending stiffness the same. Fiberglass is a cheap and easy fabric to use for this. Sandwich a medium weight glass cloth with a two carbon layers and that should work fine for fairings and such.

#3

My SM fenders are 3 layers of 200gsm twill. They flex similarly to plastic.

I found 2 layers were to flimsy and 4-5 were too stiff and fractured if the bike was dropped.

However i’ve just done a rear fender with 200gsm twill/800gsm biaxial/200gsm twill and it flexs more than the plastic part.

#4

Hi I to make my own parts,I would not bother with any core material,not needed,I usually use three layers 200 gram twill,and where fixing points are ad additional fabric where I think stress will be applied,some times Kevlar,you can use two layers,first layer for cosmetic look,backed up with carbon cut into square pieces overlapping each other,so where they meet there is central point of stability,it’s how sky scrapers are made,and looking at some moto gp panels some use this process,so many variables,if I could upload photos I would,for some reason I can’t, if I was you infusion would not be the way to go,I have experimented myself and got better results from wet lay up,but it is personal choice,

#5

Thanks for the info and advice, i was hoping i could get away with 2 layers but it sounds like 3 will be needed.

#6

If you want to make part more cheap, just use polyester cloth in the middle over 200gr. This will give strong part and cheap. Many companies especially Chinese are using only 1 Layer of Carbon fiber 1 layer of Polyester 250-280gr and 3 layer Polyester cloth 140gr. The surface results are the same except of course the flexibility and brakes more easily.

#7

Do you have any idea how much resin a polyester cloth of about 200gsm traps? Does it make the part stronger because of bigger thickness of the part or it is strong itself?