Fiberglass + Metal = ??

[Absath]

From any of you that have had fiberglass parts (such as Z3 vents for instance) installed into your stock metal fenders or wherever, have you had any problems?

My main concern is that you're joining two different types of material, and that over time they might separate, warp, etc. Have any of you had experiences like this?

[PATDIESEL]

Well warping won't just happen, even under extreme temps the earth just doesn't get hot enough or cold enough to change the shape of the metal. It will crack pretty easily around the seams though if bumped. The metal will bend and then bend back into shape if hit lightly, the fiberglass will not bend at the same rate and will crack the seams. This goes for combining any two different materials. eg. fiberglass and urethane will not mix at all b/c the urethane will bend so much more easily then fiberglass. For instance if you look at where Mazda fixed the plastic grill into place they left some play in the attachment points. This is so that when bumped the materials can flex at thier own rate and not break one or the other. Then they will flax back and you'll never notice a difference. The problem with ZE inserts is that you have to bondo them into the fenders. There is no way to give them independant flex room.

[Absath]

So essentially if I were to have fiberglass vents installed, I would have to be VERY careful about contact to the car, correct?

Has anyone here had things like this installed, and then cracked the seams? I know that they're not invulnerable, I'm just looking to get an idea of how truly fragile they are.

[mitmaks]

you could use body filler between fiberglass and metal

[DavidOS]

instead of body filler you could use that 3m foam body filler s--- is sticky and gets fluffy and hard as a rock.