CF poles and Comfort shaping....

Hi,

New poster here.... Got interested in hammocks as lightweight alternatives to tents and pads. And as an inveterate DIY guy I came across this forum. I've made clothes, sleeping bags, overbags with Gore-tex, and a few boats... Been reading a bunch here over the last few days and decided to join.

A couple of things have come to mind in all the reading I've covered.

1) CF poles - have you guys looked at the kite building suppliers? CF poles are common in a whole range of sizes/weights and in nesting diameters and with inserts for joining in lengths. Kitebuilder.com is one such source. They also sometimes have interesting fabrics in very light weights at good prices (sale prices...) .75 oz or even 0.5 oz.... Not great for hammocks, but probably fine for very light cat cut tarps.

2) In the HH diassembly thread there was some minor mention of bias cut material. It looked to me like they are indeed bias cut, but there is very little notice made of that. Bias cutting is likely a vital part of the "comfort" and apparent "flatness" and the final little bit of the secret of the HH hammock.

The reason is that Bias cut fabric has more give and conforms much better to curves as the fabric is more able to distribute the pressure to other threads around it (assuming the threads aren't bonded to each other in some fashion like PU coating or silnylon.) This means that high pressure points will cause more give in the fabric in localized areas and this will make the sling/bed conform more naturally. The downside is that its likely that the edges of the hammock would require binding to maintain strength. Not really an issue if you're making something like a bridge hammock, but more work if you're making a whipped one. This knowledge comes from extensive fibreglassing experience where bias cut cloth will fold cleanly over a much sharper edge and conform tightly to compound curved surfaces where flat laid/cut cloth won't even come close, without bubbles, puckers, wrinkles and folds.

Has anyone experimented with the bias cut idea?

Looking forward to making a few hammocks and seeing what works best for me and my best girl.

First off, welcome to the forums.

Due to the development of the Bridge hammock, I have been looking into CF pole quite a bit. There are several sources out there. I will check out the website you listed. Finding something that would allow you to break down CF poles into smaller sections would be a great benefit.

What exactly do you mean by bias cut? The HH body is made from a rectangular piece of fabric and the shape of a HH comes from the asymmetrical shape of the netting, side tie outs, and the whipping/folding technique.

Rapt,
By bias cut, do you mean cut the fabric at a 45 degree angle to grain of the fabric?

I'll have to check my HH tonight to see if it is bias cut.

For homemade hammocks I don't think it's really an option since we use the full width of the fabric (usually 60-63"). You have to have some really wide ripstop to be able to make a bias-cut hammock out of a single piece of fabric.

Yes,

Well actually bias cut means the threads of the weave of the fabric are at an angle (any angle not just 45 degrees) to the rectangular shape.

So instead of the threads running parallel or perpendicular to the length and width of the hammock, they run at an angle (or bias).

This is a standard sewing term and is used in making clothing that fits, drapes and conforms better.

Good point about fabric width, it may require some tweaking or wider width fabric, or worse yet another seam. Also bias cut fabric tends to not holds its shape as well prior to sewing so its somewhat harder to sew with since you can't pull very hard on it without pulling it out of shape.

Experiment with a small piece cut in a square on an angle and then pull on the various sides to see what happens.... :)

I understand the HH is a rectangular piece, but in one close up photo it looked like the warp and weft (threads of the fabric) were at an angle to the sides of the rectangle.

Seeing the direction of the weave is pretty easy with ripstop.

The more I think about it, a bias cut would be undesirable for a hammock. Since you are lying diagonally in the hammock it would be more comfortable for the hammock to stretch in that direction. You wouldn't want the length or width of the hammock to stretch. In other words, you'd want the grain of the fabric parallel/perpendicular to the centerline.

I don't think we have a choice since most of our ripstop comes 48" to 60" wide we can not cut a piece long enough on the bias without making a seam.

Good points... :)

As Redtail kind of eluded to we sleep on the diagonal, which in effect is lying in the bias directions, and therefore taking advantage of the stretch and conforming nature of a bias cut.

That's great site and resource.

What kind of performance fibre would make the best lightweight tarp that could double as a poncho?

welcome to HF rapt.
about those light weight fabrics... .75 oz or even 0.5 oz.... Not great for hammocks, but probably fine for very light cat cut tarps.
are they water proof or maybe DWR treated?
they might make a good hammock shell or quilt. ...tim

FWIW, I think someone said that the weights listed for kite fabrics generally do not include the weights of any treatments applied to it.

Quote:

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Originally Posted by headchange4u

First off, welcome to the forums.

Due to the development of the Bridge hammock, I have been looking into CF pole quite a bit. There are several sources out there. I will check out the website you listed. Finding something that would allow you to break down CF poles into smaller sections would be a great benefit.

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I hear ya HC. I'm trying to get a hold of some aluminum .5" and .43" poles to see if they will hold. I know the .625 is fine. Then I can look a bit harder at the CF.
From that kitebuilder site this looked promising.
Not bad at 70g for 5'

Also, the previous link you passed along on the Bridge thread.
But, I keep remembering what Ron Bell said on his site

".355 outside diameter Multi-Ply- Multi Direction carbon fiber construction- Not just a simple pultruded or wrapped in one direction tube like cheaper CF poles"

I wonder if that's the same as kitebuilder talking about unidirectional and a radial wrap??

I went back to the graphitestore site

So it seems the uni, pultruded isn't the best way to go but go for the uni-rolled wrap like this one
Read the remarks there.
So I still don't know which CF to get.....

Quote:

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Originally Posted by slowhike

welcome to HF rapt.
about those light weight fabrics... .75 oz or even 0.5 oz.... Not great for hammocks, but probably fine for very light cat cut tarps.
are they water proof or maybe DWR treated?
they might make a good hammock shell or quilt. ...tim

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I went to the Challenge Sailcloth website to try to find more specs on some of the fabrics listed. The lightest (eg Elite 36) are decribed as PU coated "zero porosity". The heavier ripstops (eg 1.5) is listed as "Resin impregnated". Think that means silicon? Anyway you can match up brand names from kitebuilder to the source for more specs. Look like North Sails is also a source.

Thanks for sharing the Kitebuilder.com link Rapt, very interesting stuff there.

Those fabrics are zp (Zero porosity) which means that they are typically impregnated with a plastic resin... Usually melamine or polycarbonate (mylar) as a liquid (melted) that soaks the fibres and is then rolled flat and thin between metal rollers. Should be waterproof and totally NOT breathable.

The sailcloth is really neat stuff, and often direct source can be cheaper but quantities are usually huge. Kitebuilder often has sales on seconds or overstock that is cheep. I bought a bunch at less than $4 a yard....

Like someone else mentioned I'd use it for tarps, but probably not a hammock.

people use spinnaker sail cloth for tarps.

i bought some kite cloth a while back. it feels like magazine paper, it was listed as .75 oz, but the coating is extreme, and it is much heavier than silnylon.

yes, i also would like to know if the hh is cut on the bias. can anyone tell? the older hh's that i've laid in didn't have anymore stretch than a reg. cut hammock. if they were cut on the bias, i would think there would be a very noticable amount of stretch. hennessy has alot of crazy stuff in his patents that he doesn't actually use in his commercial designs.

i would think a hammock that was cut on the bias would stretch way too much, causing sever shoulder squeeze. for instance, 1.1 stretches more than 1.9 and so it has more shoulder squeeze. a bias cut would stretch way more than even 1.1, i would think.

My HH (Expedition) does not appear to be bias cut. The "grain" of the fabric runs parallel/perpendicular to the sides.

I am very familiar with ZP from when I used to skydive. You do not want to make a hammock from ZP. A fly maybe, but not a hammock. It's like wrapping yourself in mylar.