Has anyone made your own clear filler? I’ve lots of parts that made out of prepreg carbon, but few of them got voids all over. I’ve read there are black filler available but I do not want the black filler to be visible once clear coated nor clear coat the parts 3+ times and sand it. I am thinking of adding some kind of resin thickener (like cabosil or similar) to make it paste like then rub it in the voids, will this method work? anyone got any suggestions?
Use a liquid rheology modifier, like Byk 410, instead of Cabosil. The cabosil will leave white/blue spots.
how do you apply the byk 410? do you simply just add it to the mixed resin then it become gel coat like or are there special instruction for the mixing?
That will take more than 3 coats of clear to cover. I sometimes have to clear my parts 5 times before its pinhole free, and these are pinholes you cant see from an arms distance away.
I would brush that with some epoxy. Maybe mix it up, wait for it to thicken up a bit, apply it, then use a heat gun to lower the thixotropy enough for it to get in the voids.
That is a good suggestion carbon, It has worked for me on small pin holes before.
What prepreg are you using?
Just mix it in with the resin, and after a few minutes it becomes thicker.
Just try to keep pinholes to a minimum 
did you try other ramp rates/ dwell periods? And how is the air evacuation?
The best way I tried is epoxy, because it self levels. Just brush it on top of the pinholes and then use your gloved finger and slide it across the surface this will fill the gaps. After it cures you will have to sand it flat though.