First wet bagging results - a little help needed

General Composites Discussions Composites Talk
#1

Hi,

I’ve just demoulded my first carbon fiber vacuum bagged piece.

It has 3 layers of 200gsm 2x2 twill CF and the resin is Sicomin SR1500.

I wet layed up the first layer and let it partially cure, then I layed 2 more layers and vacuum bagged with a vacuum pressure between 0.5 and 0.6 bar.

When i demoulded, there were some milky patches on the surface as well as small to large pinholes and small areas where there was no resin coating ( although I believe the fabric is wetted)

These are pictures of the results:

The milky patch seems to be resin with a lot of micro bubbles.

-How can this be avoided?
-Is this structurally dangerous or just a cosmetic issue?
-If I sand the piece and then do a thin coat of epoxy can I “hide” these a bit?

Thanks

#2

Letting the first layer partially cure is the main cause imo.

What was your vacuum stack?

#3

em02057,

I would agree with the above comment. Letting your initial surface ply partially cure isn’t going to help your process. Other issues look like it may be bagging technique. It is a belief that just vacuum bagging a component will force all of the composites to the surface of the mold and create a nice part… unfortunately this isn’t the real world truth. There are many techniques to creating a good composite piece and unfortunately if a critical step or technique is overlooked, the part won’t come out as expected.

The most important key is that you are actually out there, hands on, trying it out. Although educated study is going to help out a great deal, all of the study in the world won’t build a part, there comes a time when you just need to go ahead and try… and thats what you’ve done! Great job! Looking at that piece as your first attempt, I’d say that with a bit more education into your technique you’ll be making nice parts in no time!

To be honest, if you’re are looking for an aesthetic panel, it is hard to beat the look of a good infused piece.

You may want to look into switching to an infusion process? Your choice. Good job though… never stop learning!

-Corban