I use mainly ooa prepregs in automotive application. Our biggest supplier is Advanced composites, from wich we use a body panel system. That’s somewhat similar to infusion in the curing cycle, but behaves like a prepreg in layup. SP/Gurit has a similar system, called sprint. I don’t have issues with pinholes, and an excellent surface quality, but you do have to keep some things in mind, oherwise you’ll have air trapped between the outer glass layer and the carbon layer. The resin is coloured, so you have to lay all the fibre’s perfectly on the mould surface, otherwhise you’ll end up with dark spots. I’ve seen excelent surface quality from SP Prepregs too, but not that much hands-on experience.
Delta from italy(mentioned earlier) also provides good prepregs. We had some troubles with (a lot) of pinholes, but some fiddling around with our cure cycle fixed that, so we had pinhole free surfaces. I get better results with “real” prepregs than “resin sandwiched” prepregs, and I find them nicer to work with. But Body panel systems do provide a faster layup, and therefore are cheaper. I’d say, contact the companies mentione here, get some information from them directly, ask some test samples, and work out the best methods for you.
The ones I use go as low as 65 degrees celcius. It seems the higher temperature does provide a better quality, so I prefer to cure at 100 degrees celcius. A lot faster too. also, the Tg is higher, not unimportant for a car with a black surface standing in the sun. A freestanding postcure is possible, so when your tooling can’t take the heat, you can cure at 65 degrees, and postcure later. Or just neglect it, an see what happens (our company slogan…)
