Oct 12, 2010 at 6:58 pm #1264334
Looking to make a single hooped bivy for my Peru trip in 3 weeks and curious if anybody knows which poles have the most bend-ability, of those available from the usual channels.
I want to do a full short arch within a pretty narrow space. Maybe 36" wide x 24" tall as an arbitrary baseline?
Thanks!Oct 12, 2010 at 7:42 pm #1653982
@retiredjerryLocale: Oregon and Washington
I went to http://www.polesforyou.com/index.htm in Vancouver WA and they bent some Easton 7075 Aluminum poles for me.
They used a crude plywood jig. It was a quarter of a circle as I remember. The radius of the circle was smaller than the desired hoop radius, because the pole springs back. The guy bent it several times and asked me if that was enough, then bent it some more. There was a metal loop at one end of the circle to keep the pole in place and he pulled at the other end of the pole with his hand.
I used 0.344" tube for a hoop that was maybe 45" wide and high.Oct 12, 2010 at 7:42 pm #1653984
@scfhomeLocale: Chocorua NH, USA
The old Early Winters Omnipotent tent had in fiberglass what you want (there is a thread with pix from last year); but, as far as I know, none such are available today. Easton Mountain Products has a new tent with a tight radius carbon hoop, but they don't sell the poles separately, and haven't seen the tent close up anyway to verify the bendability. That's why the manufacturers prebend some of the poles in a hoop, or use elbows at the apexes (e.g. Montbell Crescent).
Quest Outfitters has a good selection of elbows, and if you are only going to use one per hoop, get the Easton alu sections, also available from Quest, as they will tolerate the elbows much better then the carbon that IMO is only reliable in high radius bends.
Roger has a machine that prebends alu without using heat (that affects the tempering); so I know it can be done, but don't know where here in the USA. So elbows are probably the better way to go. Look at Roger's pix on bushwalking.org.au to get clear ideas on using elbows with both carbon and alu to make hoop tents. The link is in Stuart R's Oct 12th post on the 'Spinnshelter – esque' thread.
At one time, I used the type of quite bendable solid quarter inch fiberglass used for pennants for the top arc sections, and typical alu for the lower sections; but was never really satisfied with this approach because an elastic cord could not be strung through the whole hoop.
Sorry that I don't have more info, but hope this is helpful. Maybe someone else can provide exactly what you seek.
Sam F.Oct 12, 2010 at 9:20 pm #1654022
@davidadairLocale: West Dakota
Just a thought- Walmart sells a 5'x 6' junior kids tent with thin fiber glass poles for $19.00. The poles are 7 pieces, 10.5 feet long and weigh 6 oz each. Which works out to 16 grams per foot including connections. I had a set and found they can easily be bent to the radius you are proposing. They also seem stiff enough for that application. You would have to cut the section lengths and restring the elastic of course.Oct 12, 2010 at 10:35 pm #1654037
Thanks guys, much good input to think about.
I'll probably order a few sections and elbows and see how close that gets me, if that doesn't work I'll call Tentpole Tech and see what they can do.Oct 12, 2010 at 11:43 pm #1654040
drowning in spamMember
I would think the smallest diameter poles would be the most flexible. I can't remember where I read it before, but filling the tube with sand before (pre)bending is good for preventing kinks.Oct 13, 2010 at 6:57 pm #1654336
Many companies use Delrin rods or something similar for lightweight hooped bivies, and of course as pack frame components and more. Cheap and easy. Check this out:Oct 14, 2010 at 9:03 am #1654503
Brad, that seems to be the route to explore, I didn't even think of Delrin.
Thank you!Oct 14, 2010 at 9:36 am #1654513
Sure! One thing I'm not sure about sourcing is a ferrule or joint. I'm tempted to say you could use, say, 1/4" ID rubber tubing, but am not sure it would be rigid enough at the joints. I don't know where the aluminum (?) ones people use come from.Oct 14, 2010 at 10:31 pm #1654771
@scfhomeLocale: Chocorua NH, USA
The kite material websites have lots of ferrules, including aluminum alloy. Goodwinds is pretty good with specs on the weights and diameters, but you may have to call to get the lengths. I think Quest Outfitters also sells Easton alu ferrules separately. Sometimes you can get the right diameter on pole sections or tubes and cut them into ferrules. I've never been unable to find the right size ferrule if I go with internal or external, whichever can be found in the right size.
Sam f.Oct 15, 2010 at 8:13 am #1654826
Thanks Sam- I was wondering about cutting chunks of tent pole, but it seems like it could be "interesting" to get them to match. Totally spaced on kite sites!Oct 17, 2010 at 9:55 pm #1655491
@jumpbackjackLocale: Armpit of California
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