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I want to use a woven carbon fiber tube in cloth form to act as an acoustic absorber in a 40 mm internal diameter pipe. The bad news is that it has to carry a variety of solvent/air mixtures at temperatures up to 80 °C.

When it is cut to length the ends fray horrendously. Now, an obvious way to stop this would be to put some tape around the end. Unfortunately I cannot find a tape that can withstand alcohols, ketones, hydrocarbons and chlorinated hydrocarbons. The solvents are why I am using carbon fiber in the first place. I could move to glass fiber but I expect I would encounter a similar problem.

How can I stop the cut ends of the mat from fraying?

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    $\begingroup$ If you did move to glass fiber, I imagine you could simply heat fuse the fibers at the cut ends. $\endgroup$
    – Air
    Apr 26, 2016 at 15:50
  • $\begingroup$ @Air I tried that but it turns out to be too difficult in practice. Not sure why, but probably needs a very precise application of heat. Running a flame over the ends does not work. $\endgroup$
    – Dirk Bruere
    Apr 26, 2016 at 15:52
  • $\begingroup$ I'd have tried a hot iron so that you can apply some pressure at the same time, but I haven't worked with glass fiber so I'm speculating. $\endgroup$
    – Air
    Apr 26, 2016 at 15:54
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    $\begingroup$ If you are just using the carbon fiber as an acoustical absorber, why not use nomex sleeving instead, it absorbs sound better than carbon fiber and the cut ends are easy to "tidy up". McMaster Carr has the sleeving in OD's from 1/4 inch up to 2 inches. $\endgroup$
    – William Hird
    Apr 27, 2016 at 2:50
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    $\begingroup$ @DirkBruere: Porex Inc. sells PVDF foam, will that do? :-) $\endgroup$
    – William Hird
    Apr 27, 2016 at 14:48

4 Answers 4

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One solution would simply to hem it as you would any other textile if it's just for the ends of a tube blanket stitch would be easy enough to do by hand and should do the job.

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  • $\begingroup$ Not sure how thrilled the people in production might be, but it seems like a possibility $\endgroup$
    – Dirk Bruere
    Apr 26, 2016 at 16:26
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Stitching it like Chris Johns mentioned would be a good solution. Carbon fiber is typically sold in a tow (untwisted bundle of fibers), but with a large gauge needle you might be able to get it to work on a standard sewing machine. There will probably be some fuzz to manage as fibers are broken in the process, but would be much easier than by hand.

It may be a bit more expensive, but a carbon fiber yarn would likely behave much better in the sewing machine. Also Goodfellow carbon fiber yarn.
Reference book: Design and Manufacture of Textile Composites

There are likely a number of contractors that will preform this stitching. Their prices are likely very high, but they may be a good resource if it proves to be more difficult.
Kuka Robotics
LayStitch Technologies

Another option would be to pinch the ends of the carbon fiber fabric between graphite, metal, or other material to mechanically hold it (rivets or other).

Another, less advisable but possible quick fix solution would be Muffler Putty (Exhaust Cement) sold at local auto parts stores.

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I would use a low viscosity epoxy dip on the tube end and going/polish with an air flow and mask, when cured with repeated operations as required for surface finish.

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Ring mount the material:

Cut the cloth oversize. Mount between two rings with a bead of epoxy or other resistent material, then trim.

Depending on how much force is on it it may be sufficient use a ring with a groove and inert O-ring.

A third idea is a pair of rings with a layer of inert deformable plastic between them -- PFTE is one such, but PE is inert for the purposes you mentioned. Note that you can buy meshes used for filters in a variety of plastics. May want to reexamine why you need carbon fiber.

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