Talk Composites - The Forum for Advanced Composites

Peel ply on pre preg

http://www.talkcomposites.com/Topic37471.aspx

By carbon man - 7/15/2020 9:26:26 PM

Will this work? Mabe release film then peel ply?

I'm trying to achieve a uniform flat finish on the back on the pre preg part, and not lines of resin that need sanding out to allow the cover to fit. 

I tried release film and then breather and it worked great, but it left the face of the carbon with pin holes in.

Using xpreg xc110.

Thanks

By explorecomposites - 7/23/2020 7:39:24 PM

 
carbon man - 7/18/2020 12:41:43 PM
 
Chris Rogers - 7/17/2020 7:53:27 PM
Peel ply will pull about 40g per square meter worth of resin from your laminate.  If you can keep your resin by weight fraction above 30% then this is probably fine.  Might have some surface porosity issues if you bleed a lot of resin from a very thin laminate.  It is very standard to use peel ply on pre-preg!

What you're after is called a caul plate - a semi-flexible B-side tool that provides pressure but also leaves a nice finish.  If the shape is simple but curved a piece of silicone sheet can work.  For more complex shapes you'll need something soft but that holds a shape locally to keep the part smooth but not reduce the pressure of the bag.  These can be cast silicone or latex in a production environment.  A thin stretchy rubber sheet might work... do you have a picture of the geometry?

Thanks I might try silicone sheet. Would this go direct onto carbon or still use release film? 

It depends - probably release film would be safer but plenty of parts that aren't going to get secondary bonded are cured against silicone and if the silicone itself is fully cured transfer shouldn't be an issue.