How many layers of carbon fiber weave?

[DND]

How many layers of carbon fiber weave "should" go into a body part made of CF?

[A4Rob]

Most companies who are making hoods are using fiberglass mat 9several layres, then overlaying CF on top of that. If you are vacuum bagging molds of fenders or hoods, i would suggest at least 5 layers of weave.

[DND]

Hmm, I've got a hood I can see through...

[onemoremile]

That isn't right. My Vorsteiner has one good layer for the vents, maybe another for reinforcement under the rest of the hood, and then a layer of honeycomb reinforcement.

Of course, it still cracked.

[jrock]

Make sure each layer is criss-crossed too for structural purposes.

[onemoremile]

think of it as plastic plywood.

[DND]

Right, my point being that I probably should not be able to see daylight clearly through the resin from one side to the other.

[geeky]

Right, my point being that I probably should not be able to see daylight clearly through the resin from one side to the other.

correct

[mike-2ptzero]

The parts only need 1 layer of CF for the outer skin. The frame work will need multiple layers of CF or FG.

I can see right thru my Fiber IMages Hood, trunk, fenders and doors when you put a light behind them since they are just 1 layer of CF.

[DND]

So then what you really have is a body part made of resin with the CF serving only for aesthetics and to prevent disintegration when it breaks?

[A4Rob]

One layer without reinforcement is like paper. You can bend it with your hands.

[mike-2ptzero]

One layer without reinforcement is like paper. You can bend it with your hands.

CF is meant to bend and flex, it is the gel coating that cracks if it is bent too far. The frame is the reinforcement. When using fiber glass it should be layered to increase strength.

[onemoremile]

So then what you really have is a body part made of resin with the CF serving only for aesthetics and to prevent disintegration when it breaks?

That is the nature of composites. I've even used t-shirt fabric for moldmaking. It cuts easily and even tears.

Carbon fiber, kevlar, fiberglass, FRP, etc. are fibers saturated in and encased in plastic. More layers saturated in resin means less flexibility and more strength. Real strength comes from the frame and curves have more rigidity than other shapes.

[Greg@DTH]

The hoods I will be making for the B8 will have a total of 7 layers of carbon fiber and be one solid piece that wil never need hood pins or delaminate.

The process we will be using wil have the upper skin laid up with three layers, then the lower frame will be four layers, all 6.5oz.

The two layers, in thier repective molds, will be sandwiched together (with extremely lightweight calibrated foam in the voids where the inside frame is off of the hood).

Once the molds are sandwiched and sealed, the resing will be injected in and vacuumed out, the mold will then be autoclaved (heat and pressure) and the part will be fully cured in less than an hour.

Molds are then removed and the foam is melted out with solvent. The end result is a hood that is one solid laminated piece that can withstand hundreds of miles an hour speeds with very little flexion or distortion.

[DND]

Wow, sounds nice.