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Tapered Mandrel for 6in airframe and couplers

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BlazingAngel665

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Looking for someone who would be willing to part with or manufacture a (preferably) aluminum tapered mandrel for composite layups. PM me with offers please.
 

watheyak

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How tapered are we talking? Just enough to aid in removing the part from the mandrel? I went down that rabbit hole a long time ago and it's way more trouble and expense than it's worth. Removal from a straight tube is easy and cheap, relatively speaking.

Polish the tube, use Frekote as the release and pop it in a freezer (or MA winter) and done. It also helps if it's cured at an elevated temp.
 
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BlazingAngel665

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How tapered are we talking? Just enough to aid in removing the part from the mandrel? I went down that rabbit hole a long time ago and it's way more trouble and expense than it's worth. Removal from a straight tube is easy and cheap, relatively speaking.

Polish the tube, use Frekote as the release and pop it in a freezer (or MA winter) and done. It also helps it it's cured at an elevated temp.
Exactly that tapered. We've had success removing tubes from straight mandrels before, but it was . . . messy.
 

watheyak

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The problem with machining a taper like that is you get many spiral ridges in the surface which need to be polished out. That polishing trashes your tolerances making it low and/or out of round in some spots. Which then makes it harder to remove thank if it wasn't tapered in the first place. Now granted, this was explained to me 15+ years ago, things may have changed since then, and your polishing may be more precise than mine. Or your budget may be way higher. :)




Well I added those photos but deleted the associated text and the photos. Not sure why they still show up.
 

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Rob702Martinez

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The problem with machining a taper like that is you get many spiral ridges in the surface which need to be polished out. That polishing trashes your tolerances making it low and/or out of round in some spots. Which then makes it harder to remove thank if it wasn't tapered in the first place. Now granted, this was explained to me 15+ years ago, things may have changed since then, and your polishing may be more precise than mine. Or your budget may be way higher. :)




Well I added those photos but deleted the associated text and the photos. Not sure why they still show up.


Was that Prepreg, in or out of autoclave? Nice piece.
 

watheyak

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Thanks. This piece was just a wet layup with Aeropoxy and lots of compaction. So far the only non-prepreg composite part in this project.

The point I wanted to make was that they were pulled off the mandrel by hand, but then realized that might nor be relevant to the original poster's 6" part. I deleted the text but the photos persisted.
 
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