My method to the madness... Expensive, but it works!
There are a lot of repair materials out there, but most of them are specifically designed for two or three types of plastics. I forget how many types of plastics that are used in automotive but it's something like 36? And identifying which one you have is kind of tricky. Someone out there must know what a yamaha hood is, but i don't.
SEM Makes an excellent product called "Problem Plastic" Which can be used on all types of plastic. SEM also makes reinforcement material. You'll need some if your repairing a crack. A good plastic cleaner is Crutial! before you start make sure you clean a large area around the crack. SEM has a couple great ones. after cleansing heres what you do-
1. bevel crack on each side with 36 or 80 grit by hand or mini grinder (slow speed!) you don't want to "smear" or melt the plastic
2. Scratch surrounding area on back side with 36 or 80, sand front side first near the crack with 80, and then surrounding with 180.
3. spread a thin layer of Problem Plastic on back side, then lay down a strip of repair cloth, spread another thin layer of resin, put a second strip of cloth down trying to criss cross the first cloth, and spread your final layer of resin. This is all done while wet, and be quick, it hardens up fast.
4. Spread as much material on front side as needed to fill the beveled edges and taper it off away from the crack, making it easy to featheredge off.
5. Sand front side with 180, 220, 320, and maybe add a coat of putty, and your ready for primer.
Like I said, a lot of steps, but it's worth it after you forget the crack was ever there, This is of course assuming your painting the hood. Lol If not, well hell I'd go with a drill and zip ties.
