Talk Composites - The Forum for Advanced Composites

Hand layup and vac bagging

http://www.talkcomposites.com/Topic2676.aspx

By pedcrist - 8/24/2012 11:04:26 AM

Hello,

I´m trying to make a fender for two times, but i have always the same problem.

The process was:

- 2 layers of wax

- 3 layers of PVA

- hand layup

- perfurated film, breather and vac bag

When i pull the vac i payed attention and made wrinkles with the bag in the corners, but it seems not working.

The result of the firt attempt:









The result of the second attempt:









The mould was like this:







If anyone know what am i doing wrong, please tell me.

Thanks,

Pedro
By AlpacaChris - 7/14/2013 2:10:35 PM

Pedro - 

I used to get voids and pinholes all the time on deep complex guitar shapes.  They always came down to fabric being pulled way from the walls of the mold during vacuum.  Sometimes it was the vacuum bag pulling, sometimes it was the release film or the breather fabric.   This is why injection molding and silicon bagging material fixes these problems in production;  the fabric doesn't move.   My best advice is to be very careful, and work on cutting pleats in the release and breather fabrics so they don't interfere with, and pull on the CF when you first apply the vacuum.  Once the vacuum is applied, poke at the trouble spots and make sure everything is seated properly; look for spongy areas.  

Good Luck!

Chris.