quick working with bondo question, adhearing bondo to fiberglass Options

[celicarocker]

ok, im ordering a set of the z3 fenders, becuase mine are trashed and i need a cheap replacement... i dont like those vent things by the door. now ive never worked with this stuff, but i have had alot of experience with plaster on walls, and sanding that stuff down...

now is it basically the same thing? id glob the stuff on in the holes, wait for it to dry, then sand it smooth, right? like i said i do it to walls with spackle all the time, so it shouldnt be that hard... but is that basicially the steps?

[madmods]

No bondo! Cut out the vents, rough up both the front and back. In the back lay fiberglass cloth to cover the complete hole. Overlap the hole in the back. After it dries, cut fiberglass matt and fill the exact size of the hole from the front. Sand and finish up with a filler that has fiberglass strands in it. No bondo.
Its funny, because I ordered the z-3 fenders too, and Im going to cut the vents out and add some custom ones and get rid of the bottom vents.