I’m trying to degas my 500cp epoxy resin in glass jar. I’m able to apply -0,925 bar (about 27,3" of mercury). There are tons of small air bubbles expanding to some point. Problem is they don’t want to pop. They just expand. Few of them pop of course but there is an army of others which don’t pop. I was trying to heat resin. Little improvement, but nothing extra. Also shaking had no significant result. Whats the problem? Little vacuum? Or change resin?
i would say, change the resin. i use two resins by r-g ,one for layup and one for infusion, and after mixing, if left alone for 2 minutes, they totally degass by themselves.
could be not enough vacuum, and TIME!!! One time I left a standard epoxy in there for 30min longer than normal…and it was clear. Now I know that I never wait enough…or realize that at least most are gone 
Its all in how you stirred the resin the first time.
Also, turn the vac on and off to pump the air out of the bubbles.
And why i the world would you want to use a glass jar???
that would be a dangerous mess…
Glass jars are fine unless you have a pump which pulls about -5bar…
Pour from one container to another in a long thin stream…
Consider this - a light bulb, with paper-thin walls, contains a vacuum. Won’t be any issue for the kind of vacuum levels we do. Positive pressure, on the other hand…now THAT would get ugly!
Could be water absorbed in the epoxy. I degass epoxy (without curative!!!) at ~50C for a couple hours when I get a new lot. Mixing, laminating, or even pouring from one container to another will put air back in, but you aren’t going to get around that easily. Some guys do double vacuum bagging so you can degass the laminate without bag pressure for a while before you move to the traditional bag and bleed step.
Werksberg good idea, I was using it when working with silicone rubber.
I will try different resin.
Thanks for your help
Try exposing the jar to vibration whilst the vacuum is applied, maybe sit it on an aircompressor, vibration can help pop the bubles.