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David Neumann
(idahomtman) - M

Locale: Northern Idaho
Re: Fibraplex Carbon Tent Poles on 02/03/2009 12:22:58 MST Print View

I have had these poles for my BD Firstlight for several years and have had no problems with breakage. I just ordered a set for a BD One Shot I bought used and hope that they work equally well. The weight savings are substantial enough for me to justify the cost.

Samuel C. Farrington
(scfhome) - M

Locale: Chocorua NH, USA
Fibraplex Carbon Tent Poles on 02/08/2009 15:17:00 MST Print View

A few thoughts that might be helpful:
The stiffness of carbon poles varies a lot. If an arrow shaft, it is called "spine," or the amount of deflection below level when the shaft is suspended over a 28 inch span and a weight a little under 2 pounds is lowered onto the center of the shaft. A shaft with more spine will tolerate a greater bend (smaller radius), but will deflect more in the wind. I guess the trick is to see how much deflection the whole pole (sum of the shafts) will tolerate before failure without too much deflection.
Roger, forgive the use of the word,"torque." My interest is finding some way to compare the relative strength of the shafts, and my thought was to use a "torque" wrench to measure the number of pounds of pressure needed to break the shaft. This would be with strong alloy tubing telescoped at least 2 inches over each end of the shaft, and maybe 12 or so inches of shaft exposed.
I would like to know which shafts are stronger before making the poles and subjecting them and myself to the elements, and would appreciate any thoghts on a simpler or better way to test them. I would also be remiss, Roger, if I didn't thank you for your very helpful and valuable articles and comments on this site.
About the inquiry about materials for ferrules (connecting inserts), the kite companies have pultruded carbon tubing available in many diameters. Determine the inner diameter of a carbon shaft, and you can order pultruded tubing to make the ferrules. Breathing and eye protection are vital when cutting the carbon. I use a mini-cut off saw with a thin steel blade purchased from one of the tool warehouses. Arrow suppliers also have saws with composite blades. The cut ferrules must be buffed smooth at the ends, with care later not to split the ends whenever assembling the poles. I have never had one of these ferrules fail, as they are thicker and stronger than the shafts. As pointed out many places on this site, they must be quite close in diameter to the shaft inner, or their ends will create a pressure point on the shaft inner.
I like Roger's approach also, using carbon shafts with a stiff spine, and prebent alloy tubing connectors at the corners. At least at one time, Fibraplex sold alloy connectors.
But I'm not ready to give up on flexing the carbon over an arc. Am also not keen on snapping expensive carbon tubes to see what it takes to break them. Have pretty well settled on the Easton Axis Nano shafts with a half inch spine, connected by pultruded carbon ferrules, and as earlier mentioned, may try a Carbon Express shaft also. The arcs will be around 43" high and quite long at the base. Will try a short one on Tarptent's Scarp 1 first for the center pole. Will let you know how it holds up here on Mount Chocorua in our regular spring gales. Should add that I tried carbon on a modified Mont-Bell Crescent 1, and due to the high degree of bend, much more than on most "dome" tents, I had many snaps whereas the DAC featherweights did not fail. Settled on a laminated carbon/alloy shaft purchased from Cabella's some years ago which is much stronger than carbon, but several ounces lighter than alloy for the whole pole, and had no failure (yet).
Sam Farrington

Raymond Estrella
(rayestrella) - MLife

Locale: Northern Minnesota
Re: Fibraplex Carbon Tent Poles on 02/15/2009 08:39:10 MST Print View

Hi Ben,

I have FibraPlex CF poles for my Seedhouse SL2 too and have been using them for a few years now with no problem. I use them with the tent body and with the fast-fly set-up in winter.

Dave bought a set at the same time and had a break at the front hub. He did not send them back as he says he will never trust them again.

Kevin Egelhoff
(kegelhoff) - F

Locale: Southern Cal
Re: Fibraplex Carbon Tent Poles on 02/15/2009 14:14:08 MST Print View

Samuel,
Spline is typically considered the stiifer orientation along the horizonal axis of the tubing or poles, not based on deflection. We actually have test fixtures that rotate shafts or tubing to find the "Spline" of the tube. If designed properly, it is almost impossible to find a "spline" in a tube or pole. When bending a tube, it will typically rotate naturally to the weakest orientation during bending or deflection.
You also mention pultruded tubing from the kite manufactures. If you are really looking for the strongest tubing possible you would not want to use a pultruded part as it has much less carbon fiber and much more resin in the process of making the part. Resin is the binder that holds it all together but is also the weak link so a engineered tube with "pre-preg" has much more carbon and less resin and is therefore a much stronger but way more expensive process in making a tube. I'm using pre-preg that is now as low as 24% resin compared to pre-preg from just a few years ago using 35% resin.
I think the real key in making the parts stronger lies in the material used and the orientation of the fibers as designed for the part. Are these parts being desiged using mostly 0 degree fibers running along the axis for stiffness, or a combination of 0 degree and some 45 degree plies to reduce the torque, or even some of the fibers laid up at a 90 degree angle for crush strength. All of these are critical in the design process as well as testing out the parts in test fixtures to see if the parts meet the designed criteria.
Kevin

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Fibraplex Carbon Tent Poles on 02/15/2009 14:19:36 MST Print View

Hi Sam

Happy to help.

> materials for ferrules (connecting inserts), the kite companies have pultruded carbon tubing
I have used that myself - Avia kite spars, worked well. But they don't leave a big hole down the middle if you want to run bungee cord through them.

> may try a Carbon Express shaft also
DON'T! DON'T!
Carbon Express arrow shafts may be very nice for arrows. But they are a complete disaster for tent poles! Been there, tried that, smash-up.

The reason is that Carbon Express shafts are NOT carbon fibre tubing, despite the name and the very carefully worded advertising. They are pultruded glass fibre with an extremely thin cosmetic dress layer of carbon fibre over the top. Bend them a bit too far and they spilt down the full length like any other pultruded tubing - and this happens much sooner than with genuine CF tubing.

I won't go so far as to say that Carbon Express are fraudulent, but all their marketing is carefully worded to make you think the shafts are carbon fibre, while not actually saying so in that many words. Maybe they make good arrows - I wouldn't know.

I bought a lot of Carbon Express for some tents, pitched the first one at home, and the tubes split immediately, there on the lawn. I took them back and demanded a refund! (and got it.)

Cheers

dan mchale
(wildlife) - MLife

Locale: Cascadia
tape on 02/15/2009 15:40:35 MST Print View

I've got some I have been trying for awhile in Integral Designs MK XLs. After breaking the end of one pole section; not sure if it broke during set up, winds, or just cramming tightly down the inside of a pack, I wrapped generous amounts of adhesive tape around the ends of all the sections. I used that because I wanted to see if a fix could be had with materials I might be carrying. A denser tape would be better. So far they have held up. I'm not sure if newer ones are reinforced or not, but they should be - kind of a no-brainer. They absolutely need ferril reinforcing. I have much more confidence in them now.

Edited by wildlife on 02/15/2009 15:53:12 MST.