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Fixing nick in carbon fiber prop

agent4573

Well Known Member
Hoping for some guidance on how to fix a nick in a composite whirlwind 300 prop. It's on the trailing edge of one of the blades and was found during the most recent 50 hour inspection. It's not large, but you can definitely catch it with your nail. My first thought would be to just add a drop of epoxy to it and try to sand it back to flush. I am worried that my sanding will leave a large, very noticeable area on the blade unless I sand it up to 5000 grit and then polish it. Anyone have any experience?
 

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Chip Repair

I also have a chip in my WW prop blade. The guys at Texas Propeller told me that they fill small chips with Super Glue. I haven't tried it yet, though.

Ron B.
 
Hoping for some guidance on how to fix a nick in a composite whirlwind 300 prop. It's on the trailing edge of one of the blades and was found during the most recent 50 hour inspection. It's not large, but you can definitely catch it with your nail. My first thought would be to just add a drop of epoxy to it and try to sand it back to flush. I am worried that my sanding will leave a large, very noticeable area on the blade unless I sand it up to 5000 grit and then polish it. Anyone have any experience?

I had a nick quite a bit larger than that on the trailing edge of my MT composite prop. I repaired it with a little epoxy that I mixed with some black paint pigment. Formed it up with a little peel ply, then sanded it down after it cured.
 
Good Idea

I had a nick quite a bit larger than that on the trailing edge of my MT composite prop. I repaired it with a little epoxy that I mixed with some black paint pigment. Formed it up with a little peel ply, then sanded it down after it cured.

I like this idea and will try it on my prop. Thanks for sharing...

Ron B.
 
I had some similar rock chips in my WW200RV prop - called Whirlwind and sent them some pics, they said as long as the fibers under the epoxy are not "damaged" then repair with epoxy and smooth it out as desired. If the fibers are good, it's cosmetic.
 
I also have a chip in my WW prop blade. The guys at Texas Propeller told me that they fill small chips with Super Glue. I haven't tried it yet, though.

Ron B.

Back in the ultralight days, we would fill that with crazy glue and baking soda. That is some tough stuff!
 
Or us J-B Weld for the epoxy -- dark grey, nearly black in color and tough stuff. I've used it to repair wood/composite props over the years.

Yeah, any kind of epoxy would be fine. In my case just I picked up some Devcon epoxy from my neighborhood hardware store and while there I just asked them for a bit of black pigment from their paint department.

JB Weld is good stuff...the grey version has metal fibers impregnated. Probably overkill for a low-stress application like the trailing edge of a propeller, and especially a tiny nick like OP's, but certainly as good as anything.
 
Hysol

Depending on the color use Hysol 9460 or 9462. Both thixotropic and have at least 45 minutes before the onset of partial cure. Takes 24 hours to cure and 72 hours to fully harden. I used just a drop of 9462 for the off white side of my blade. The thixotropic properties make it self leveling. Clean up with alcohol like most epoxies.
 
The MT manual recommends 5 minute epoxy! Any epoxy will be OK. As it is only a very small ding only a small drop will be needed, perhaps cut to shape with a sharp knife before the epoxy is fully cured.
 
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