bonding fibreglass to platsic. would it crack?

[jaffaz32]

If i wanted to bond fiberglass to a plastic panel and fill it so it was smooth and no joins would this last or would it crack?

How would you go about this?

 

[69XSN]

If i wanted to bond fiberglass to a plastic panel and fill it so it was smooth and no joins would this last or would it crack?

How would you go about this?

From my experience, it depends on a few factors. If the bonded area does not have to support too much weight and is not subject to too much vibration or flexing, then it should be fine. Be sure to properly prep the plastic/fiberglass e.g. rough sanding to increase bonding surface area and clean surfaces correctly. Also, mix the plastic filler correctly, apply generously and give the bond ample time to cure before you start sanding or cutting.
I´ve done this to bond a fiberglass diffuser to my plastic rear valance. It has been good for a little over a year now, but then again my car is not a daily driver, so your experience may vary. Good luck.

 

[eyecandy]

Scuff the plastic really rough, and use panelbond or other high end professional adhesive. Even then, its no guarantee it wont crack in the future.

 

[Factor X]

I'm a composites engineer, and funny - I just got fatigue-testing data back from my last urethane/epoxy bonding testing. We passed 2,000,000 cycles at 25% ultimate load.

I would do surface prep with 80-grit, acetone wash, and use an industrial/aerospace epoxy paste. If you want something more flexible and shock-resistant, a good urethane or methacrylate adhesive would be better. In some applications, even a 3M pressure-sensitive adhesive tape (double-sided) will last forever.

FX