What level of vacuum do you use during infusion + write your resin type (epoxy, polyester…)? Do you hold same level of vacuum during infusion and same for curing?
I read that its bad to cure resin under full vacuum.
Thanks,
Mike
Highest vacuum possible.
VE and Epoxy only.
Full vacuum until fully cured, never reduce vacuum for curing.
Thanks for exact answer 
that is what I needed to hear.
What TET said.
try to get as close to 29.7"Hg as possible. Never below 27"
Same for me.full vac untill cured
riff is it harder to get a successful infusion pulling less than 27" of vacuum? my pump only does 24" max
That should work fine.
What is most important is to not have any leaks AT ALL. Absolute vacuum is not so crucial, as long as the only way into the bag is the resin feed line(s).
Ah ok thanks for clarifying that.
You can also make cyclic compaction/release. The thickness of the preform will be lower each time you compact it so you can achieve higher resin/fiber ratio with same level of vacuum. You can read study about this preform hysteresis in Boeing CAPRI patent.
Yup, it nests the fibers and the tows together, a little at a time. Remember though, your permeability will drop as well, so if you have problems using a thick resin, it will get worse. Infusion times will also increase.
And yo are right TET, I am normally in the research frame of mind. anything below 27" is unacceptable. Now, how I got -0.4% voids in my last part is beyond me. Guess that ion pump worked out!
Sometime, even great looking tool or molds will leak from the backside…
If this reply was to me…I said -0.4% voids…not 0.4% voids!!
Metavoids? Anti-voids? Not sure what to call them. Negative refracting voids? 
How is a negative void possible?
Maybe they had bumps from porosity that didn’t exist on the tool?
well…that was my point. It’s not possible.
I blame the drifting density scale…don’t know how else it could have gone wrong. Weigh the sample in air, weigh in water, burn off, weigh again…
24hg for vacuum infusion; get some thin resin… 400cps or less.
So true… good reason to make frp molds at least 1/4" thick imo.
Thickness is not much of a factor there. The gelcoat and first couple of plies just need to be applied properly.
Does anyone know the difference between a SMALL amount of vacuum change, in the different steps of an infusion?
Our house vac is 27-28, 29 on good days. My small tabletop vac pulls 29.7 easy, if not more (new analog gauges)…
Would it make any different to maybe pull the 29.7 during the infusion, and switch to the house vac for the gel time/cure? That sucker runs SO hot, I’m scared I’m going to cook it!!! (Gast SAA-V109)