Finishing a Composite project, need some help.

General Composites Discussions Composites Talk
#1

Hello everyone,

My name is Ryan and i’m very new to the composite game. My Brother and I are refurbishing an Old Jetski and i came up with the Idea of doing FO-Carbon Fiber on the handle bar post. The Post is made of plastic but we used WB 400 epoxy resin and covered it with a sheet of Carbon. The question that i have is this.

AS expected, since we did not use a mold or vacuum of any kind we have airbubbles in at the very surface of the resin. we also have some thin areas that have the whole snake skin look going for them. What i was thinking, and let me know if this is ok, or if there is a better way. I would litely spot sand all the surface bubbles. Then scuff up the peice, and apply another coat of the WB 400. let that dry, litel wet sand it, and finish it with an automotive clear coat. To cut off the extra fabric, we are going to apply extra WB 400 to the areas to cut making sure it is nice and stiff. Then we will rough cut out the shape, Sand it, re Epoxy the edges then run a thin black pin stripe around the edge to hid it before apply the clear coat.

This is what it looked like before the carbon, We used black tinted fiberglass to get a round shape.

Then after the Carbon it looks like this.




Thanks for you time.

#2

Depending on the resin u use I would do a light scuff and clean and add another heavy coat of resin. Block smooth and clear. Looks good in the picture! But I know in real life there is a difference.

#3

Ok so i have reapplied another coat of Epoxy and it came out very milky. I thinking it is from very tiny airbubbles. I’ve just about sanded that entire coat off to restore the luster, but i want to know how i can prevent this from happening again. Can i thin the resin with acetone to allow for the bubble to come out? any tips would be great. It’s taken use about 7 hours of wet sanding with 220 grit to clear it up. I can’t beleave how hard this resin is.

#4

You need to degas your resin. You can place the mixed epoxy in a vacuum chamber. Or place your mixed resin on a hot plate. Be very careful how long you heat it though. A small test might be a good idea.

#5

I do not have these bubbles in the cup after mixing. or atleast i can’t see them. I thought it might be that, so i mixed up a batch nice and slow trying my best not to whip it up.

Should i try to use a roller to apply coats or is a bush good enough.

thanks for the help.

#6

It could be from brushing the resin on. what you could try is hitting it with a heat gun after you brush your resin on. This will pop the bubbles. maybe try it on a test piece first.

#7

Thanks, I do this for the large bubbles. However these are like Micro bubbles that take a ton for heat to remove. So much heat infact that it Kicks the resin.

#8

The tiny ones could be in your resin from mixing. You may not see them when the resin is in the cup, So you might want to find a way to degas your resin after mixing.

#9

What type of brush or other tool do you guys use to put down resin when hand laying? I think it might be the brush.

#10

personally i would have used surfboard resin not epoxy.