Today I made a test panel with flax fabric and biaxial fiberglass. I was wondering when you have to clamp off the vacuum line after the panel is completed infused? I waited until I almost didn't saw air bubbles and I had at this time already a lot of epoxy in the catch pot. Can I wait to long before clamping of the vacuum line, so there is not enough epoxy any more in the fabric? Of course the infusion side was already clamped off. 
I know there can be a lot of moisture in flax fabric, so is it a good idea to put the fabric in a kind of oven, so it's completely dry before starting the infusion?

It depends if you have a resin brake or not.  With a decent resin brake, very little resin will get past the brake into the catch pot and traditionally that is how infusion is done, and many still do it that way.  In our experience, for cosmetic parts, we tend to switch it around a bit.  We let the resin get to the vacuum line, then clamp off the vacuum line.  Leave the resin feed open for another 30 seconds to a minute then clamp that off.  The extra resin can help with pinholes and voids by having a slight excess compared to a perfect fibre:resin ratio.  You can, with experience, vary the extra time you leave the resin feed line open to get the best results.  However clamping off both lines means you MUST have a very good leak tight bag. 

With Flax it can be dried before use or you can, after the leak test, leave the bag under vacuum for a few hours or overnight to help drive out moisture.

Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

+x

 

Warren (Staff) - 3/31/2022 3:56:00 PM

It depends if you have a resin brake or not.  With a decent resin brake, very little resin will get past the brake into the catch pot and traditionally that is how infusion is done, and many still do it that way.  In our experience, for cosmetic parts, we tend to switch it around a bit.  We let the resin get to the vacuum line, then clamp off the vacuum line.  Leave the resin feed open for another 30 seconds to a minute then clamp that off.  The extra resin can help with pinholes and voids by having a slight excess compared to a perfect fibre:resin ratio.  You can, with experience, vary the extra time you leave the resin feed line open to get the best results.  However clamping off both lines means you MUST have a very good leak tight bag. 

With Flax it can be dried before use or you can, after the leak test, leave the bag under vacuum for a few hours or overnight to help drive out moisture.

OK, thanks for the advice!