bonding tubes

[carbongr]

We are building a carbon fire frame for a wheelchair for a customer. The mould is a rather complicated one, consisting of 14 individual moulds. The idea was to laminate the two halves of the tubing and then bond them together.
What should be the best way to bond the two halves of the tubing (in respect of adhesive and method we should use)? The wall thickness is 3mm.
Thanks,
George

 

[berkshire]

carbongr

You do not say what diameter your tubes are.
On a tube over about 2" in diameter you could use a stepped lap joint with a tape over the outside for security.
If the tubes are smaller than that, I would not suggest making them in two halves. Use one piece tubing and a tape wrapped finger joint.
The tapes should be woven carbon or glass.
B.E.

 

[carbongr]

thanks for the reply and advice.
The tube O/D is 1"
George

 

[MikeHalloran]

That's an obtuse way of making a tube.. and it removes all the benefits that carbon fiber might otherwise bring to a tube. Calculate the shear stress on the bond surface when you bend the tube.

You might want to study 'filament winding' and 'tape winding'. Simpler tooling, stronger tubes.

You'd still need moulds for the lugs to join the corners.




Mike Halloran
Pembroke Pines, FL, USA