so, a few weeks left in the design phase of the new car. That means, busy times coming up for me building it!(and building 5 other cars…)
Currently the first plug is being cnc’d so we are getting everything ready. I’m not happy about the old method we use. It’s a epoxy gelcoat, epoxy carbon, backed up with a epoxy paste. We had some issues with the epoxy resin ,Tg was 60 degrees celcius, curecycle had a top of 85 degrees celcius! So a lot of print trough, and just falling apart, because the gelcoat just delaminates after a while. But that’s sorted now.
The main thing is the warping of the moulds. The epoxy paste (basically epoxy+sand+fibres) is great for creating stiffnes fast, but it’s brittle, and has another expansion as the fibre.
So when it ran out, I just didn’t order it anymore, that problem is solved too 
This week we have another project, making some panels for a curved projection screen. I plan on using the epoxy gelcoat, with the carbon epoxy layup only. Should be quite allright. Does anyone have experience with this? I’m a bit worried about the shrinkage in thicker layups, as little as it will be with epoxy. maybe a spreaded out layup to prevent heat(=shrinkage) building up is the way to go? This product isn’t that critical, but some parts for the car will be, so this is a nice test 
Does anyone have experience with poly/vinylester based systems for prepreg products? Cheaper and quicker, but I’m a bit worried on the cycles they are to survive…
Does anyone else want to share their toughts?