Make an Ultralight Carbon Fibre/Fiber Tarp Pole Set (78g)

This project was about learning how to work with Carbon Fibre/Fiber more than it was about saving weight. The total weight saved when compared with the Aluminium tubing that it replaced was around 70g. That's the equivalent of a mouthful of water. Even so, at 78g it is still well over 100g lighter than the lightest set of carbon fiber trekking poles on the market

The carbon Fiber poles in this project were designed for one DIY Tarp/Tent that I've previously made. I also wanted to make the poles modular. There are probably going to form the basis of a tubing set that can be used with a variety of tarps that I own.

For this project I'm not giving any price guidelines. Carbon Fibre/Fiber is relatively expensive to buy and relatively delicate to work with. It's easy to make an expensive mistake unless you have some reasonable skills in the workshop.

This particular Tarp/Tent is pitched with a short rear pole and a long front pole. I've designed each pole to illustrate the two different techniques that can be used to create small and large tent poles in Carbon Fibre/Fiber. The two projects also illustrate where weight savings are made and lost.

Short Carbon Fibre/Fiber Tarp Pole (23g)

This short pole illustrates the limits of not using Aluminium. Sure the pole is going to be very tough but the weight saving was a mere 6g. The reason is simple - that Aluminium fittings were required on the tube and these are 10g of the total weight. The Aluminium tube of course doesn't need them. This pole then is very close to the cross-over point where weight savings and strength improvements do not justify the material costs. More...

Long Carbon Fibre/Fiber Tarp Pole (54g)

This long pole is more than twice the length of the short one, uses heavier gauge tubing and yet is a lot less than twice as heavy. At this length the extra weight of the Aluminium fittings are much less significant when compared with the overall pole weight and so this Carbon Fibre/Fiber tent pole is less than half the weight of the Aluminium one that it replaces. More...

Working with Carbon Fibre/Fiber Tubing

The stuff that I am using is pultruded carbon fibre tubing. It is very strong vertically and very stiff vertically. It has very little horizontal flex when placed under a vertical load.

It is reasonably crush resistant but still has to be treated with care - it cannot be uncrushed. The safest way to work with it is to assume that it cannot be clamped in any sort of vice without risk of damage and so to work with that limitation in the design.

Like many mass-market tubing the external diameter of the tubing is reasonably accurate (in engineering terms) but the internal diameter of the tubing can vary somewhat - 8mm may be 7.9mm or 8.1mm. It is not going to be anywhere near engineering grade - 8mm+/- 0.01mm unless you are very lucky or very rich.

The tubing will split quite easily if you try and insert any misfitting or even close-fitting tubing inside of it. If you tried to force (by hand) one aluminium tube inside of another and they wouldn't quite fit then nothing would happen. If you tried the same thing with carbon fibre tubing the outer tubing will split (I have a split tube :-(

For all intents and purposes then the tubing size that you have both i/d and o/d is the one that you have to work with. I often find that Aluminium tubing needs machining to get the i/d to be a usable dimension but this is impossible with carbon fibre tubes.

It follows from this that the only way that you can create internal ferrules that will fit your tubing is if you have access to CNC and can machine parts to produce a good fit.

Even so, I feel that given the characteristics of the material, for any given diameter the external ferrules will be a more practical DIY alternative - they are easy to machine to the correct size and will offer more protection to the tubing.

The tube designs here were done so that my first set of poles would work. The material is too expensive to make mistakes with...