Well its been a couple of years since I have had all the carbon stuff out and decided recently to get out an old mold and make a few parts. unfortunatly my little black book of notes (of mostly things that dont work) is AWOL. The part is a welding sheild (picture darth vader but shallower) anyway, I am using 1 ply of 8.3 oz 4x4 twill,waxing mold with rexco or partall paste #2, brushing on a surface coat of epoxy (US Composites #635 thin/med cure), letting it get well past the b stage (just past a brush leaving marks)then brushing on another coat of epoxy then lay my pre cut fabric in place (which has a mist of spray adhesive on the side opposite the mold surface) then dabbing with brush to completley wet the fabric while adding some more epoxy as required. once its all wet I lay down Airtech ecnostitch or perforated release film, a couple layers of breather cloth then put the whole 9 yards into a large ziploc bag and pull 25" of vacuum umtil its cured. the problem I am having is small voids where the weave of the fabric is (not in the surface coat). Its not that bad but I dont seem to remember having this problem before. Is this being caused by too much vaccum? If its a vacuum issue should I ramp it up or just pull less vacuum. the part has an embossed area (raised in the mold surface) for the lens which is .25" high so the main reason I am using 25" is to ensure fabric will conform to the step and degas the area.I am also using a silicone rubber form to help in this area but could probabley get away with less vacuum here. Thanks for your input
Try Airtech Dahltexx SP2 as a peelply. Works wonders. (this will draw the air out, not the resin)
thanks for the input. I did figure it out. I was allowing the epoxy surface coat to cure too much which was not allowing it to become one with the layup.