I have been hand laying fiberglass for years but new to vacuum bagging. I did a test of 3 layers of 6oz on glass but I get these small air voids in finish and not sure why. I used west system epoxy and under vacuum for a hour or so. Any help would be great. Thanks
Vacuum bagging process without use of external pressure greater than atmosphere pressure can be difficult to get a good surface. If you want a good surface, I suggest you do infusion process. If for some reason you can’t, or don’t want to, you can try some additional things as follows: use P3 perforated release film (helps control resin bleed) between peel ply and breather. Use a steel roller to remove the air prior to vacuum bagging, play around with your vacuum level, time before vacuum, and resin systems. Careful on your resin content, you should only have tiny resin dots where the perforation in the release film is. If your breather gets fully saturated, that’s not good! At the end of the day you will find that switching to infusion process would be more worth doing. Good luck
Thanks for the reply. I did try another test piece with the p3 and worked better for holding in some resin and making the part a little stiffer but still had the same surface issues. Not sure if west system 105 is meant for bagging?
I am going to try the infusion process and see how that works out.
That resin does not like extremely low absolute pressure.