CF fin weave

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David Schwantz

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Just got some CF fins. The weave is very open and course. What are some of you doing to seal and or smooth the surface before gluing to tube?
 
I'd hit it with a spot putty if bad enough, or a filler-primer if not so bad. But I'd mask the areas I intend to be involved with glue and fillets. Not sure I'd bother with it before they're attached, though. Might be just as easy to wait until everything is glued together so you don't have to worry about masking.
 
Bondo and or putty is out. I want the CF look. Thought of just coating with clear epoxy then sanding smooth. Clear epoxy and vacuum bagging them. Last ones I did like this I just filled with clear coat, which worked but took lots of coats.
 

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I've fixed it both ways. (many clear coats and epoxy)

The last few times I just brushed on epoxy and sanded it smooth, but vacuum bagginb might not be a bad idea to get rid of the air bubbles in the pinholes.
 
As far as the air bubbles go, a light pass with a torch will pop them. I do that on the epoxy tables I build. Would not think that would warm the CF.
 

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Are the fins from Wildman? There was a thread a while back that talked about these parts.

https://www.rocketryforum.com/threads/finishing-carbon-fiber-fins.161315/
If I were going to try and "fix" the appearance, I would cover the flat part of the fin with laminating epoxy and peel ply. I wouldn't bag them. If there are bubbles under the wetted-out peel ply, you can use the tip of a chip brush to tap on the peel ply. That will remove the bubbles (it's magic). You will then have a flat fin with a peel ply finish, but where the voids are filled. You might paint the surface with one more layer of epoxy, but at that point, you should be able to sand the fin flat without sanding into the carbon itself.

Jim
 
already applied the epoxy and have them "in the bag". Did not have any peel ply and cannot see any bubbles. Will see what they look like tomorrow. I will post a pic, good or bad. thanks everyone.
 
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