Feb 2, 2009 at 9:30 am #1233742
I've used Fibraplex carbon tent poles — in a 5-pole / 2-hub design for my BA Seedhouse 2 SL tent. The result was quite poor actually, as I experienced 3 separate incidents of pole breakage.
I'm wondering if the poles are just downright lousy — or perhaps they are just not suited for the Seedhouse configuration?
For those of you who own a simple dome tent (meaning just 2 poles criss-crossed at the top like an "X") and use Fibraplex carbon poles — what are your experiences with these poles — esp. in fairly heavy winds?Feb 2, 2009 at 9:46 am #1474757
@mrmuddyLocale: No Cal
I had a BD Lighthouse
Used these poles..
Went to move the tent .
The small cross pole broke..
Fortunately, one of my buddies had a pole repair sleeve with him.. That saved me..Feb 2, 2009 at 11:27 am #1474784
The poles are not adequate to support mzny of the dome/arched tent designs IMHO. Had two breakages with the Nallo2 when there wasn't even any wind…and they are very dangerous when they break!Feb 2, 2009 at 2:07 pm #1474820
@scfhomeLocale: Chocorua NH, USA
I have used carbon tent poles since the mid 90's without any serious problem. Initially, I made them out of carbon arrow shafts ordered from Cabella's, and also ordered better and very light weight shafts from Barry Venderhorst's ad in Backpacker magazine (no longer in business, as far as I know). One mistake I made initially was going too light with the arrow shafts, but I recall only one break, which was clean and was quickly replaced by the extra shaft I carried. I never had a break with Barry's shafts, still use them on my Wilderness Equipment bug dome with fly, and regret that he wound up his business. More recently, I have experimented with pultruded and wrapped tubes sold by several kite makers' materials sites. I did order a set of shafts from Fibraplex, but found them, as well as the ferrules (connecting inserts), more brittle than other shafts I had with minimal testing, so have not used them. There are also the new FX pole shafts available from Easton, but while bomb proof, they are on the heavy side, more in the weight class as DAC's alloy, and require an expensive minimum order for more than one needs for just one tent. I am currently looking at Carbon Express Maxima woven and Easton Axis Nano arrow shafts for my next project.
I have thought about testing a number of these shafts with a torque wrench until they break, and reporting the results on this site. Please advise with a post if there is any interest.
While the above might otherwise belong in the DIY column, wanted you to know why I feel that carbon does have potential to improve substantially over alloy shafts. It is a matter of quality of manufacture, and using the ever improving technologies.
Hope you find this information helpful. Thank you.
Sam Farrington, Chocorua NHFeb 2, 2009 at 2:36 pm #1474833
I would find the testing interesting for sure. However I feel pretty strongly that Roger Caffin's method of using arrows to form an arch without putting them under any torque is a much more robust use of CF arrows. I just wish someone made them commercially like that as I don't have the engineering skills and equipment to make the joiners/ferrules.Feb 2, 2009 at 3:33 pm #1474853
As many of you will know, I use CF poles on my summer and winter tents. They have endured some extreme hammering. But, it is possible to break CF poles, and I suspect that simply putting them into unmodified domes may be taking a bit of a risk. Why?
The reason is that the radius of curvature at the top of a dome is actually quite small – often under 1 metre (yard). With Al poles the vendor puts a pre-bend into the middle sections of the pole so that the strain on the poles in the field is not too high. I am sure you have seen the slight curve in such poles. (I have done that too.)
But you cannot put a prebend into a CF pole. So a CF pole is already very close to its limit when the tent is just sitting there. Pick the tent up and bounce it, and you can go over the limit and bang! This may be why Fibraplex poles have snapped for some people: they were overloaded.
If you look at my tents you will see that all the poles have corners or bends in them. That's where most of the curvature is found. The straight CF poles never get anywhere near their bending limit – and so they survive very robustly.
CF poles with corners for curvature
PS: it is not 'torque', it is simply 'bend'. Torque does not happen with tent poles with ferrules.Feb 2, 2009 at 3:51 pm #1474860
>But you cannot put a prebend into a CF pole
Is it (theoretically) possible to make CF poles with the bend already in them (ie manufactured with a curve rather than straight)?Feb 2, 2009 at 3:59 pm #1474861
Thanks for your feedback and insights. I think I will skip the Fibraplex CF poles for my dome tent…Feb 2, 2009 at 4:46 pm #1474878
"I think I will skip the Fibraplex CF poles for my dome tent…"
Which is a…….;)Feb 2, 2009 at 4:53 pm #1474880
> Is it (theoretically) possible to make CF poles with the bend already in them
Yes, of course.
But no-one in the world has worked out how to do this on a production basis, and especially how to get the metal former out from inside the tube.
To explain: most CF tubes are made on a round former or mandrel. A typical example would be some 1/4" metal rod finished off in a centreless grinder. The CF material is wrapped around the rod tightly and cured. Then they have to get the metal former out from inside … not so easy, but possible by temperature differential.
Now, two questions: how do you make a curved former exactly right, and how do you get it out later? Ouch!
Third question: how do you do this at a price the market would bear? We (customers) do not have the Pentagon's wallet. :-)
CheersFeb 2, 2009 at 6:44 pm #1474923
If tent manufactures could get Easton/DAC and friends to make poles specifically designed for a particular tent design, (IE pre-bent to a particular angle that of course would differ from model to model) for a "reasonable price" (and small qty) then we would have some interesting choices.
Rather then pre-bent poles, I have "post-bent" poles , after some use some pole sections retain part of the curvature. At this point if I had CF pole sections there they would be ex-poles.
FrancoFeb 2, 2009 at 7:05 pm #1474926
Here are reviews on our site:Feb 2, 2009 at 7:20 pm #1474929
I have a very different perspective about Fibraplex poles.
If you see the reviews above, I tested them to failure (see the extremely tight arch I created before they snapped) and have now used them extensively in 3 seperate tents (BD Lighthouse, Gossamer Gear/Tarptent Squall Classic, and Terra Nova Laser Competition). After years of using them in extreme conditions (high winds on an exposed ridge above Camp Sherman on Rainer, for example), I can only report one failure in the field.
That failure was when I lent the tent out and failed to explain to my friend the deal with these poles. Here it is:
They are wicked strong IF you get the fully seated. You must fully seat them to achieve full strength. If you don't pay attention and get them to fully seat (not hard, but you do have to check) then you put force on the weaker ferrules. When fully seated, they are very strong, although not as STIFF as Easton FX poles or heavy aluminum poles (but on par with the stiffness of DAC poles).
But if you know how to handle these poles (and again, I have many, many nights with these poles and no breakages under my care), you will be very happy with their performance. I would buy them for nearly any tent and have on several occasions.
That said, I HAVE snapped an Easton FX poles in the field (fell on the tent- idiotic move) as well as an aluminum section (high winds). I've bent aluminum poles on several occasions. Based on this record, I would say that the Fibraplex poles are quite strong when used properly. But like any carbon fiber product, these will break rather than bend when pushed to failure.
Best, DougFeb 2, 2009 at 8:41 pm #1474958
Doug — thanks for your insight and links.Feb 2, 2009 at 11:45 pm #1474990
> They are wicked strong IF you get the fully seated. You must fully seat them to achieve
> full strength. If you don't pay attention and get them to fully seat (not hard, but you
> do have to check) then you put force on the weaker ferrules.
Yeah – like this:
That was from a tent I sold – but the owner cheerfully admitted they did the wrong thing.
CheersFeb 2, 2009 at 11:55 pm #1474992
As stated above, I managed to accumulate 3 CF pole breakages! Believe me, after the first one, I always took extra care to ensure that each section was mated completely with the next. Didn't stop the next two breakages from happening though. I was thinking perhaps the Seedhouse's 5-pole / 2-hub design was just not suitable — but reading the above, I think the CF poles — at least the straight ones — are both too weak (causing tents to flex too much) and too brittle.Feb 3, 2009 at 1:42 am #1475005
The photo was referring to a discussion about seating the ferrule completely.
I will have to disagree with you about the Fibraplex poles being weak. Instead I will repeat my comment about the radius of curvature of the poles at the top of the Seedhouse. It is just too tight. I have done many bend tests on CF tubing, and it has a real limit to what sort of curvature it can tolerate. Failure can be very abrupt!
On the other hand, if Fibraplex sold you those poles *for* the Seedhouse, I think they made a mistake in doing so. I don't think that tent design is compatible with straight CF tubing. A pity, but you have the proof.
CheersFeb 3, 2009 at 6:52 am #1475017
I have to agree- those are tight angles on the Seedhouse. But I saw serious gusts slam my Fibraplex BD Lighthouse and that's when I became a believer. I've found them to be very strong.
That said, a break is a break. That's what's great about the forums- you get to hear from many different experiences.
DougFeb 3, 2009 at 10:42 am #1475059
My poles broke mid-section rather than at the ferrules. This is what made the damage extra dangerous, as a broken fiberglass shaft is very very sharp and spring loaded when bent. Maybe I just got a bad batch, but it's not worth the risk for me to try again.
OTOH, I've never had an aluminium pole fail me. In fact I've experienced the Double Rainbow complete collapse and rebound without even leaving a kink in the pole.Feb 3, 2009 at 10:49 am #1475063
I use Fibraplex carbon poles with my Seedhouse SL1 and have never had a problem. I think the "hub" where the three poles meet is designed to minimize the amount of "bend" for the front two poles….they do flex, but not an unreasonable amount in my humble opinion. Although I have never had a problem, I do hold my breath when I'm setting up the tent and make quite sure that the poles are fully seated before I start flexing them.Feb 3, 2009 at 11:22 am #1475075
@idahomtmanLocale: Northern Idaho
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.Feb 8, 2009 at 2:17 pm #1476277
@scfhomeLocale: Chocorua NH, USA
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 FarringtonFeb 15, 2009 at 7:39 am #1477953
@rayestrellaLocale: Northern Minnesota
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.Feb 15, 2009 at 1:14 pm #1478000
@kegelhoffLocale: Southern Cal
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.
KevinFeb 15, 2009 at 1:19 pm #1478002
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
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.)
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