Hello my friends . I am happy to be a member of this forum for advanced composites .
In my spare time i make freedive blades from carbon fiber. After using many methods like closing first the vacuum line then after 30 seconds the feed line or the opposite first closing the feed line then the vacuum line to regain the lost vacuum , still i have pinholes / dry spots . In the link below you can see all the process in fast forward .You have to download it to see and the 30 minutes.

https://www.dropbox.com/s/xnmqseutrkk65lg/My%20Movie4.mp4?dl=0

The result of this process also had pinholes . I think that my fault here was that i closed the feed line quite early before the resin reached  the vacuum hose so it sucked the resin and made it poor.
Yesterday i made a new attempt with the same process with the difference that i didn't use the adhesive spray and also i  waited the resin to reach the vacuum hose and then i closed the vacuum line, counted to 30 seconds and then i closed the feed line.Unluckily the same results. I will take a photo tomorrow to see what i mean.
Today i made one more try witht hte diference that i waited 1 minute before i close the feed line to make it a bit resin richer ! Tomorrow  i will see the results.

Hi and welcome to the forum. 

First  point is you are using a lot of  unidirectional fibres.  UD can be a right pain to infuse because there is a lack of gaps between the fibres for the resin to soak through so almost certainly that would explain most of the reason you are having difficulties .  You would have more success if it was a stitched  UD like found in a biaxial or triaxial cloth as they have gaps between the fibre bundles which are stiched together. Whereas the UD you are using will be pretty much pure UD with either a binder or a fine internal supporting net to hold it together so virtually no gaps.

Also a second point, for  such a flat  work piece, you really should not need  a spray tack to hold it in place. - especially as you tape the edges anyway.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

It is hard to see and hear, but I think you might have a leak in your vacuum system. I think I hear the noise, which oil bath rotary vane pumps produce, if the system isn't sealed perfectly.
Additionally, if your system is perfectly sealed, your "degassing chamber" would be much to small. I usually use a pot five times the size of the resin volume, because the foam easily expands that much. Don't count on your analog vacuumeter, the point of degassing is quite a while behind the needle reaches zero (had a few vacuumeters so far, it was always the case).

and last, but not least: Don't use this jar for degassing!!! And if you really want to, you could at least wear some kind of protection. And with some kind, I mean a bomb disposal suit. no, really, Don't do it. very, very dangerous.

I attach some photos from 3 different blades.

To be more specific ,
The first layer you see at the video is  285T4  carbon fiber  1st layer
The second layer is 100 U 2 layer
The third and forth layers are 200 gr U 3-4 layers
And the fifth layer is again 285 T4 
This is the peel ply  peel ply
The flow mesh  mesh
The bag  bag
and the epoxy  epoxy

To be fair, that's not as bad as I was expecting considering the amount of UD in the stack.  Try slowing the infusion down by partially clamping the resin feed line and also make it a little resin rich.  Hopefully that will be enough to sort you out.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

I have tried all these methods. I have left the feed line more than 1 minute to make it richer, i have done the opposite after closing the feed line ( i had the vacuum line with a mesh break with peel ply only to slow down the last distance infusion so it can be also resin rich ) i waited some seconds with vacuum on to regain the lost vacuum due to the liquid characteristics . I will make a new try with different fabrics .
I will use  This fabric and This one

Ideally you want a proper built vessel or at least something that has been tested to take the required pressures and levels of vacuum without failure.

You can make a throw away  catch pot/bag by making a small bag in vacuum bagging film and filling it with 3 or 4 layers of breather cloth.  Insert it between the pump and bag and the breather will catch and soak up any resin that comes through.  It is , however, ruined after each use as the resin goes off, but can be a good temporary solution.


Warren Penalver
Easy Composites / Carbon Mods - Technical Support Assistant

Finally after making some tests i have no dry spots on my parts .I think the problem was the unidirectional fabric .Also i have to mention that i use the MTI hose. I dont do degassing . But sometimes i had an issue .You can see these tiny marks like trapped air or else which i don't know what it is and what causes this result.Any ideas ?