Newb

General Composites Discussions Composites Talk
#1

Hi,

I am new to this forum, and new to composites. I like to try things myself through trial and error, if all fails I then ask for help.

I have sourced and bought few equipment for molds, and such. But my current project is “carbon fiber overlay” . Although that is not the best route, and I am sure many of you agree. The part I am executing is a fog light cover from a '11 STi. The pegs and clips behind it seems impossible to mold and I have yet to learn how to properly fabricate such part. So I am doing an overlay.
The part is nearly done, and I have clear coated and is awaiting for more wet sanding.

My concern is, when I apply resin using a paintbrush, I some how cannot manage to have it air bubble free. When I mix the resin, there are no air bubbles, it is when I actually brush on the resin onto the CF. I’ve tried dumping it on and smoothing it out, dabbing,painting, paint/dab motion across the part. I’ve failed to keep it air bubble free. I’ve managed to fill the pockets it created with clear coat. But still can see some beneath. The air bubbles are tiny, like pencil tip, pin hole size.

For my future projects, I ask for help. Please inform on tips and advise or at least point me into a direction.

Thank you! :o

#2

When you are mixing the epoxy resin you will no doubt be adding air to it so firstly be very careful when mixing. Ideally you would be de-gassing the resin before use but that would require a vacuum pump and de-gas chamber and as you are starting out I doubt you have that equipment available yet? Another way to remove the small air bubbles trapped in the resin is to use a hot air gun, you apply the resin to the part and then run the heat gun over the resin, you will see the bubbles disappear. I have used a pencil blowtorch to do the same. Another tip is to try poly-brush’s they are foam brushes and excellent for applying resin see… http://www.jenmfg.com/poly-brushes.htm

#3

Marc.

Thanks for the tip!

I do have a vacuum pump, but I don’t have a degas chamber, I will look into that. I have yet to do the other cover, so I will use the poly brush.

I’ve tried a hair dryer but failed to get the air out, I will try to use a heat gun next time. I’ll post with results!

Should be fun!

#4

For small quantity of resin system, instead of resin trap you may use an air tight jar, like from a mayonaise (Kraft, Helmans, etc). Make a hole on the lid and use mastic sealant around the hole. It does a perfect job!
Enjoy your sandwiches! ;))))))

#5

HAHA Thanks for the tip, I like sammies.

The part I am working on is below.

#6

I’ve posted pics, but it needs to be approved.

But when it is, those are the parts I am working on, in the end I would like to make a mold. Not for profit, but for my own use. I would like to make a full carbon fiber fog light cover for my STi, but the rear clips looks tricky.

I may just cut them and some how glue them, the passenger cover would have a duct that leads to the intake. Still working on the shape of the duct and such. Should be interesting and fun. Alot of cursing and frustration, but fun.

#7

The parts can not expand much, so I would like to make a mold. Any suggestions?

On the overlay I’ve had to sand through the fiber and into the plastic on the edges in order for them to fit into the bumper.

#8

ake a look at the degassing chamber i made here:http://www.compositescentral.com/showthread.php?t=6432