Inflatable spreader bars?

[cmoulder]

lol that's where all the lightweights live.

[Just Bill]

Tested this morning with the hammock strung up fairly low over some soft, mushy snow. Per JB's suggestion, at the start of testing I put my trusty trekking pole at the head and the new UL spreader at the foot, then carefully sat on the hammock with full weight, gradually doing some small bounces to shock load a little, bounced ever more vigorously, then stretched out in the normal rest position. No worries, it didn't seem strained in the least.

Happy with that result, I put in the head-end spreader and repeated the process... again, no worries. I scooted over near the head end with all my weight in the "head pocket" area of the hammock and it still did not over-stress the spreader. Plucking the center of the spreader, it made a pleasant 'boing' and then quickly re-centered itself. VERY stable.

I was worried that the small, hollow 9/7mm tubes used on the tips might get crushed, however I wanted to see how they'd hold up without modification... they were fine, at least for this 45-minute 'ride'. If there is a problem observed later, it will be easy enough clean up any damage and put some 7mm CF rods in there.

So they were 2.5g over target weight, but not too shabby, lol.

This morning's test venue... (blurred out JB's proprietary bits):::



UL spreader bar in place:



UL spreader bar tip:

Looks like I'm late to the party- but they look great!

That's roughly 2 ounces out of the lightest breakdown set I have to date; so excellent work.
Cuttting a third out of an already light product is a big leap.

Sounds like you have thus far managed some fun and games while retaining both eyes as well which is the best news of all.

Nothing major to report but tried a new design over the weekend and shipped a 6.75 ounce Hybrid 1.2 version of what you have to another tester.

Peppy has the lighter version of that prototype (5.5 ounces if I recall)... Generally the Hybrid 1.2 seems about right at 170 ish or lighter for comfort. Much past that and it gets a bit squishy but I have laid in those at 230lbs.

Pair that with your poles however and that would put you at a 9 ounce bridge- which might officially be lighter than the micro and take the title of world's lightest.
Doubly impressive as this is a full size 36" bar bridge not a 26" FKT model.

Lots of potential here... but best to get some testing done before we go too nuts.
That said- I'm going to plug along with a few more bridges in the meantime and likely send you something if a winner pops up.

[Just Bill]

Happy to have helped nudge things forward with a few questions. The thread drift was very educational.

One other quick thought on making bridges lighter - has anyone tried orienting the fabric on the bias, at 45 degrees? It might be a bit more comfortable as I imagine it will stretch and conform to your body a bit more, of you're not using an inflatable pad. More importantly, it will load both warp and weft fibers; with warp fibers oriented head to toe, they don't see much load so there's some dead weight there. Another way to approach this inefficiency would be lower denier warp than weft.

1- you'd have a hard time squeezing a bridge into a true bias cut.

2- unneeded... as a few folks are already ahead of you (mostly).

The two best bridge fabrics (structurally speaking) are both 8 way gridstop offerings.

Dutchware's- Hexon line features this pattern with matching denier nylon 6.6 (a recent upgrade that made a huge difference)

Ripstop by the Roll= The Hybrid line has the 8 way gridstop with a hybrid denier weave. So the grid is a heavier thread/yarn and as a result very supportive. It's almost like taking a rope hammock- then weaving in the warp/weft thread to fill it.

I prefer the Hybrid- 1.7 being the better one... 1.2 proving useful for UL stuff. I have yet to have a blowout in the 1.0... but no longer use it as it's discontinued.
However since upgrading to nylon 6.6... Hexon has stepped in as a very viable bridge fabric and serves very well in the 1.6 weight to fill in the gap between the hybrid 1.7 and Hybrid 1.2. I recently started doing some prototypes in it and for some the results are promising.

If you truly got the fabric on the bias- you might find it behaved in a bridge more like HyperD fabric- which is too soft for a bridge IMO.
Awesome GE fabric- but structurally with the 45* ripstop grid I don't like it structurally.

WV is a big fan of Dutch's Dobby 1.9.
If you're not much past 200lbs... anything over 2 ounces will probably hold up reasonably. When I was 190lbs I used some plain old 1.9 ripstop which worked fine in a few models.
It's pushing things (light or heavy) where you find the issues pop up.

As far as altering warp/weft denier.... probably too hyper specialized to get someone to weave it as 99.9% of the fabric will go to a gathered end use.
Neat thought though.

[cmoulder]

Looks like I'm late to the party- but they look great!

That's roughly 2 ounces out of the lightest breakdown set I have to date; so excellent work.
Cuttting a third out of an already light product is a big leap.

Sounds like you have thus far managed some fun and games while retaining both eyes as well which is the best news of all.

Nothing major to report but tried a new design over the weekend and shipped a 6.75 ounce Hybrid 1.2 version of what you have to another tester.

Peppy has the lighter version of that prototype (5.5 ounces if I recall)... Generally the Hybrid 1.2 seems about right at 170 ish or lighter for comfort. Much past that and it gets a bit squishy but I have laid in those at 230lbs.

Pair that with your poles however and that would put you at a 9 ounce bridge- which might officially be lighter than the micro and take the title of world's lightest.
Doubly impressive as this is a full size 36" bar bridge not a 26" FKT model.

Lots of potential here... but best to get some testing done before we go too nuts.
That said- I'm going to plug along with a few more bridges in the meantime and likely send you something if a winner pops up.

Thanks JB!

I'm about 90% sure I'll be out snoozing on this setup tomorrow night... Maiden voyage!

[cmoulder]

Last night was the first serious test of the 3.6 oz (101.7g... this is for the PAIR!) CF spreader bars, and they passed with flying colors!

I was definitely apprehensive at first, and was hoping I didn't over stress them when fidgeting around with quilts etc, but after a while I was able to relax and not worry. I inspected them very carefully this morning and did not see any problems at all. I feel that if there was going to be a problem it would have been on the non-ferrule pole where it mates with the ferruled pole, but there was no delamination, splintering or cracking at all. I'm fairly certain that the snug, precise fit and longer ferrules are really important here.

Photo from this morning, after the first full night:



Having the slightly off center joint with longer ferrule meant that the section lengths were equal, which is a boon from both the aesthetic and practical standpoint:

[peeeeetey]

I just saw this thread and never considered air as structure. How about inflatable spreaders on a tarp? Sounds workable to me. pockets and a lot of seam sealer or a bladder.

[cmoulder]

Nemo once produced a tent using this concept, but I don't know why it was discontinued.

[SteelToe]

I was just about to ask this, since I'm debating internal vs. external pole mods for a tarp of my own.

I don't know if you could generate enough air pressure with your lungs, but I've inflated that stretchy latex tubing they have for sale at Lowe's before, and it's quite stout (think "balloon animal on steroids"). Include some interrupted channels on the inside of the tarp, and you would be able to easily thread such a bladder in, and also back out again to replace or simply omit for weight reasons. Tying off one end is simple, and you could perhaps lash a bicycle valve onto the other end well enough to be secure.

My concern would be that any long inflated shape would tend to be very weak against bending, but that's precisely what's needed from a tarp pole. The only way to make it rigid would be to inflate it within a sock/channel such that the ends are hard against the air bladder; that way the fabric can be pulled tight between the bladder pressing on the ends of the sock, similar to a tent pole. This would be complicated by the fact that any inflatable bladder will lengthen as it fills, so you'd also need to secure it to each end of the sock with cord or something.

[Groundskeeper]

@cmoulder. I like your pack. I thought it was a picture of an owl at first. Nice camo.

[cmoulder]

@cmoulder. I like your pack. I thought it was a picture of an owl at first. Nice camo.

Thanks, that's an old-style Arc Blast. I don't particularly like camo, but I bought it when the new style came out and somebody was selling it in order to get the latest and greatest. I actually prefer the old style and will likely buy another if I see one for sale. My first one, also old style, is still totally functional but definitely showing signs of age.