Talk Composites - The Forum for Advanced Composites

Uneven resin infusion

http://www.talkcomposites.com/Topic3657.aspx

By Slash_qm - 12/3/2012 3:11:12 PM

Hello there

I'm trying to do resin infusion with 3 layers of 200grm carbon twill, peelply and infusion mesh. I vacuum is done well I'm getting even sheet but I't s not done well with resin (see photo, holes in the joints). Ones like this cannot't be coverd with clearcoat perfectly. 
If vacuuming is bad or if not to lay infusion mesh, surface is perfect but uneven in thickness and resin consumption.

How to make it thin and with perfect surface?



http://www.talkcomposites.com/Uploads/Images/2dcd4e3a-6c19-418d-888a-c8ca.JPG
By prairiecustomcomposites - 12/4/2012 5:29:16 PM

Slash,

This looks exactly like my panel when I was having problems with leaks and leaving the vacuum pump on. Check this thread for some info on it:
http://www.talkcomposites.com/3012/Bubbles-rising-back-into-resin-cup

If I had to guess, it is that the bag or mould was not sealed perfectly and the vacuum pump had to be left running to maintain the vacuum. By doing this, you typically (but not always) suck out too much resin and end up with a part that has the characteristic lack of resin in the joints of the fibers. If you have an even amount of missing resin over the surface of the whole piece, it is likely to be the problem above. If you have sections that have large voids of resin (where the fabric barely saw any resin at all), it is likely that you developed a leak while infusing, and the air gathered in that area.

Now that I think about it, if you did not de-gas the resin, the entrapped air could potentially have come out and settled on the surface giving you the same problem.

If you can tell us about your process for your infusion, (like if you clamped the vacuum line or not, what vacuum you had in the bag before infusion, etc.) we could probably pinpoint the problem easier.

-Mike-