Hey guys, I was hoping someone could help identify what material this bonnet is so I know what I need to get for the repair job?...and then maybe how to go about the actual repair.

It doesn't look like fiberglass, but I'm no professional. The owner is letting me teach myself autobody repair on this bus. I've sanded down a bit with 60 grit to see if it would expose some fibers for me to know what material it is but that was inconclusive. It's a 2009 Blue Bird Vision, and I'm based in the US. The flat wide center of the bonnet flexes when pressed on, so it's not a very rigid piece. It is very rigid around the edges and fixtures (like headlights and such)

I'm posting photos and a video. Any help would be greatly appreciated!

Front:
https://ibb.co/qrtb2sx
https://ibb.co/28nCxKN

Rear:
https://ibb.co/vh35Ny9

Rear sanded a bit with 60 grit
https://ibb.co/9nCNf3w

Pieces of damage:
https://ibb.co/PWdSv6d
https://ibb.co/YTD7mF4

Video:
https://drive.google.com/file/d/1ODJevD ... x98AC/view

When I blow up the piece in your hand I see what appears to be a pressure laminated sandwich which probably indicates this is some type of SMC fiberglass resin composite. SMC stands for Sheet Molded Compound. This means that resin and refenforcement layers are combined in a pressure mold and compressed and heated to form the part. The part can pop out of the mold easily because the mold release is mixed right into the resin. So here is the rub on that.... you CANNOT use regular fiberglass materials to repair this. You must use SMC rated materials. All fillers, fibers, etc. will say if they are rated for SMC repair work. Parts are quite commonly made of this as it started being use all the way back in the early 1970s.

DarrelK wrote:When I blow up the piece in your hand I see what appears to be a pressure laminated sandwich which probably indicates this is some type of SMC fiberglass resin composite. SMC stands for Sheet Molded Compound. This means that resin and refenforcement layers are combined in a pressure mold and compressed and heated to form the part. The part can pop out of the mold easily because the mold release is mixed right into the resin. So here is the rub on that.... you CANNOT use regular fiberglass materials to repair this. You must use SMC rated materials. All fillers, fibers, etc. will say if they are rated for SMC repair work. Parts are quite commonly made of this as it started being use all the way back in the early 1970s.

I didn't think SMC would flex the way this does, and I thought I would see some kind of fibers on the underside, in the damaged area or when I sanded a bit with low grit if it were SMC but now I know thanks to your input. It's much appreciated.

SMC can quite literally look like anything as far as thickness or flexibility goes. You may not see ANY fibers on the other side especially if an interior layer of some reinforcement is used. That's what I see in your pic......