Repairing pressed FG - vettes and such

General Composites Discussions Composites Talk
#1

I’m going to help my buddy repair his wheel fenders on his dualie pickup truck. I’ve only repaired hand-laidup FG. This is mass produced by GM and am assuming it is the “pressed”(?) method? (I’ve heard Corvettes and other mass produced glass like this is pressed)

Do I repair it any differently? Where it is cracked and where mounting pieces are ripped off, it looks like shredded wheat. I’m “planning” on just grinding and sanding it until I get to some sound structure and then rebuilding it with PER and CSM.

Do you think this would work or is there anything special with this type of FG?

#2

For a stronger repair, use fiberglass cloth. 6-10oz should do it. The reason it ripped in the first place is because it’s cheaply made with CSM!
Other than that, your methods will work just fine.

#3

Thanks. I have a whole roll of 8oz, so I’ll use some of that. I was also thinking about using some aramid fabric I have lying around for the mounting holes.

#4

Sounds like the OEM shorted the resin matrix in those mass produced parts.

Make sure everything is well clean of dirt and oil. Wash it up with acetone or simular solvents.

If there’s any crack thru the FG part, drill a “well” hole at the ends of the crack to stop the crack from spreading.

#5

nothing special. Just CSM that is either RTM’ed, or wet layed up, and then pressed in matching molds. Any repair will be the same as most other FG repairs.

I was going to say it’s a SMC (sheet molding compound), but from the damage you described, i doubt it would be SMC.

#6

Never heard of that, but I like it.

#7

That’s how they do it in metal, say a cylinder head crack in iron or aluminium, to stop it from running before welding it up. Never thought of doing it in composite though, sounds like a good tip.