I think it is your uni materials too.

You can add a layer of a woven cloth in between the uni layers to help the resin pass through better. 

Its not easy on small parts though. You really need to both throttle the infusion speed, and have a decent size break zone.

The problem is more likely as a result of your UD layers; assuming they're running in the same direction, the fibres lock together under vacuum making a somewhat impenetrable layer that the resin can't get through which results in dry areas on the mould surface.

The peel ply goes under my resin line, across the layup and resin brake area, as well as under my vacuum line. It’s a must for uniform vacuum.

I use spiral wrap for my vacuum line and mirror it to the resin line.

I use peel ply over the resin line, and the vacuum line to protect the bag from sucking in between the spirals. The peel ply also prevents the lines from collapsing at full vacuum (which if you notice in the pic, I didnt take the time to make sure the lines didnt collapse, will work either way).

Alternatives to running peel ply across the resin brake is to take individual tows of glass or carbon and run them across the brake to the vacuum line. Spaced out like 1 inch apart. It’s even slower than using a peel ply brake, but does not effect the speed across the flow media, just the speed of the resin across the brake area. This was my old way, but now I’m lazy and just do full peel ply.

Jason

Jason

That's great. Thank you both.

Do you have a photograph or maybe a link to illustrate this 'resin break'?

Thank you very much,

Bill

Take Lesters advice for sure.  My last infusion was 14 layers thick (knife scales), the resin brake was 4 inches, and there was still trapped air coming up half way through the brake.

Jason