Carbon Fiber Question

Hello All you guys that know bunches of stuff about bunches of stuff.
I got a small question concerning carbon fiber rods.
Is it possible to bend carbon fiber rods to a permanent angle of about 30 degrees??? And if so what method would be used, heat, solvent, microwave, hot water, ice, electrical charge, etc.????
If the above IS possible by some means what would be considered the maximum angle that could be achieved???
Thought I would ask before I make a mess.
Thanks in advance.
Les
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You're going to have to settle for a 'mess.' Heat is the only way you're going to get it to bend. I don't think it is possible to make a bend to that angle without affecting the structural integrity.
I think your best bet is to do your own lay-up using carbon tow and resin.

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That rod is formed using thermosetting resins, so by definition with hest the binding resin will decompose before becoming plastic. Any solvents capable of softening the cured epoxy will destroy it - it's a one way trip, unlike ABS, styrene, etc. While they may become slightly more pliable with a bunch of heat, you're going to affect the strength of the material terribly if you try to form a permanent bend in it, esp. 30 degrees. I doubt it is possible even to coax it to stay there.
Imagine forming a part from fiberglass and epoxy. You're not going to be able to form it into something else after it has cured.
Mike D.

maximum
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Ok, thanks for the info. I was actually thinking the same thing but just want to ask to be sure. Consider the project a non-do-ABLE. Will work on a plan "B" of sorts.
Thanks for all the thoughts.
Les

30
microwave,
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make a piece of wire with 30 degree bend, bind the carbon fiber rod to each end and wrap with thread and then CA.

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If you have to use solid 'rod' then the only way is to bend some metal pushrod or something similar to the appropriate angle and then 'lash and expoxy' it to two bits of rod to create a length with a bend in it. If you can use carbon 'tube' you can epoxy and slide the pushrod metal (typically 2-56)inside the two bits of tube and end up with a sturdy piece of bent carbon fibre tube that is more slender and cleaner looking than if using rod. Cheers from Oz.

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Thanks for the suggestions but my thoughts were to use the rod as a spar to add support to a polyhedral wing thus saving weight. Adding the metal rod defeats the purpose. Although it would or may then hold the angle it would be very heavy.
Les .

you
30
microwave,
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True, but YOU can MAKE the bent joiner to fit inside the two tubes. Lay it up yourself and machine it to specifications.

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Well it would be a trade off. A little extra weight for superior strength. The insert could be a brass or aluminum tube as opposed to solid wire or bar. Hmmmmmmmmm
Ok, the brain juices are flowing again.
Thanks for the help.
Les

it
stuff.
about
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As a guide I often use the method I described to make pushrods that need a kink in them - say for exiting the fuselage and then lining up with the rudder. The metal joiner (threaded 2-56 rod to give the glue something to latch onto) I use goes into each tube about 2cm and the glue is about 3 drops each of expoxy and hardener so very little weight is added for something that's quite sturdy and about 30 cm long. As you say, a trade-off and I guess the key is whether you're working on a small park flyer where weight is far more critical than, say, a .40 sized plane. Cheers from Oz.

the
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Clive,
Your just about right. I am putting together a foam sloper and weight is important of course. The wing design has a couple of angles and needless to say possible weak spots. I was thinking of adding a couple of spars and need an angle to do it. This is what spawned the original question. I think the bent aluminum tubing inserted in the CF Tubing will do the trick. Thanks for the thoughts. "Blue Skies from the Colonies".
Les

trade-off
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Then use aluminum tubing!

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