Attempted to use the XPREG XT135 Tooling Prepreg multiple times with the same poor results.

What causes the cavities and how what can I do to get a good result?
Thanks

Please write more information about your curing schedule.

Do you use autoclave for curing that prepregs or just an oven?


Carbon fiber sheets and composites .
www.dexcraft.com

I used a standard oven following the curing cycle on the data sheet. The mold is CNC aluminum with several coats of Easy-Lease. First layer of surface carbon and a second of backing, vacuumed with perforated film and breather.
Thanks for your time

if you are using a standard oven then the ramp rate wont have been controlled, this would probably mean the ramp rate was too high, especially if you are using an aluuminium tool.
You really need to have a low ramp rate to allow heat soak into the aluminium tool, otherwise the resin will flow too quickly and you will have issues with the overall part quality.

I have been using a thermostat and incremental turning it up 2.5 decrees over the course of an hour and have had good results before. Do you think it would be adventurous to increase the temperature over two hours to help heat soak the aluminium?

Thanks for the advice, ill try it out.

No don't, follow the instructions of the XT135. XT135 needs perforated release film not unperforated.

I have managed to get good results with the XT135, but I did find it critical that the material is very very fresh. Even a couple of days out of the freezer will lead to pinholes.

Thanks for your reply's.
Makes seance that it has expired, I have had it for 5 months in and out the freezer it worker perfectly up until the 3 month mark when cavities started forming on the surface. 

As a side question, I have made a few mold using standard 6k prepreg and they work fine and only take 7 hours apposed to two days. Is there any disadvantage with doing it this way?

If it works, there's no real problem doing it. The tooling pre-pregs will have a tougher surface and so the mouds will last longer, but if you're only doing a few parts then it will be fine.