Need help with Carbon Fiber...please...

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J

jondavidj

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Joined
Feb 26, 2006
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Location
Nashville, TN
So after about 2 weeks and 15 feet of carbon fiber, I am still having issues. I have read the instructions in the library and searched this site and tried everything. I am really hoping someone could help.

Steps:

1. I put the tube in the carbon fiber and pull at both ends until tight.
2. Like in Chad Schimmel's YouTube video, I hold it and drop thin CA down the blank and hang to let dry.
3. Once it is done, I do the same as the other side.
4. At the point they are dry, I take scissors and cut to the tube.
5. I use polyester resin and cast in whatever mold I am using. Mostly, Jr Gent.
6. After a day, I look to make sure everything is ok.
7. I use a barrel trimmer to trim to the tube. (Still no white film at the end)
8. I turn the blank. This is where I tend to run in trouble.

On the ends, a white film develops. It wasn't there to start. I look to make sure that there are no bubbles and the blank is hard and there are no defects. I don't understand what I am doing wrong. It is almost like the fiber is stronger than the resin and pokes through. When I glue it, I make sure it is flat against the tube and not sticking up.

Other than this, the normal problems of gluing my rubber glove to the blank...I cast steampunk and have no issues. This one is been going for 3 weeks now and not one single blank.

Can someone offer advice?

I appreciate it!! Hope everyone had a great 4th.

Jon David Jones
 
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I use epoxy not CA. I put it on past the ends, then after it's dry (5 minute type but I give it more) I find it's much easier to trim back to the tube.
 
Hey! i don't have a ton of experience with this stuff but it sounds to me like either the resin is not adhering to the carbon finer sleeve at the end when your turning due to the amount of torque your putting on the blank or if it happens when your sanding it could be the water it getting under the resin and discolouring it, either way like mentioned above a little thin ca on the ends and let it wick down should strengthen the joint between he resin and the carbon fibre swell as prevent water from getting in! hope this helps
 
Certainly not an expert here either, but when I read of your troubles the first thing that came to mind was too much torque on the blank. It is certainly one thing to try.

Hope this helps.
 
I have had trouble with carbon fiber and fiberglas blanks with white ends. Had a friend that used to work for Owens Corning look at them, he said the fibers are brittle and that barrel trimming breaks the fibers and they pull out of the resin. He suggested that those materials should be sanded rather than trimmed.
 
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The problems I've had with carbon fiber and other casting like you described were because of a few different things. One was when trimming the ends with a barrel trimmer I put too much pressure and caused the resin to bend or bow causing it to seperate. Another was when sanding too much heat built up and caused the problem. A few other things to watch for is turning the blank too thin on the ends which you need to watch for when the cast is thick and there's not much left when turning down to size. Something else I started doing, because I read about it on the IAP, is when I have the ends squqre I seal it with thin c.a. glue to keep water from seaping in while I'm wet sanding. If you can determine when your problem is occuring and what you are doing it might be easier to solve the problem. Good Luck.
 
Tube-on takes finesse!

When doing anything in the "tube-on" style, never, ever use a barrel trimmer. They will screw up your blank every time! Use the sanding method to square up your blank.

Also, you might want to try pre-pregging your CF before you cast it. Another thing you can do is taking some 600 grit wet sanding paper and sand the carbon fiber after the CA has had time to dry. That will make a world of difference in how the PR bonds to the CF.

Are you turning between centers? (TBC) At any rate, watch how tight you tighten your tail stock . If you're really cranking it down, you will end up popping air between the PR and CF if you muscle it too much. … Just my .02¢:)
 
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