Author Topic: Portaledge Design Discussion  (Read 24117 times)

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Online deuce4

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Portaledge Design Discussion
« on: January 07, 2007, 07:28:38 am »
There are a few threads pertaining to one of my favorite topics, portaledge design, so I thought I'd bring them together in this thread:

So far:
Discussion of spreader bars, and review of the new BD hybrid design:
http://www.bigwalls.com/forum2/index.php?topic=200.0  

A short discussion on fly design:
http://www.bigwalls.com/forum2/index.php?topic=209.0

A question about bottom anchoring:
http://www.bigwalls.com/forum2/index.php?topic=214.0

(edit) A new fly concept using carbon:
http://www.bigwalls.com/forum2/index.php?topic=194.0

To answer the question about bottom anchoring, I designed the "Diamond Fly" for use in Patagonia, which had both a top and bottom suspension, so it could be anchored from below.  As many who have spent time on the vertical will tell you, when a storm comes in, often the wind from below can be tremendous as it hits the wall and travels upward.  I personally have been in situations where myself and my partner were lifted up a foot by the wind, then slammed back down again.

I made the first Diamond fly for an attempt on the East Face of Cerro Torre in 1993.  Then I made one for Brad Jarret, who used it sucessfully on the first alpine big wall ascent in Patagonia, on a spectacular route up Escudo. Heres's a drawing:


Speaking of obsolete designs, here's one of the first specialty ledges I ever made, back in 1987, the Antarctica Trippple ledge (three people, sleeping head to wall, feet out, side by side).  THis was made for Mike Hoover for a film shoot:
« Last Edit: August 17, 2013, 11:06:01 pm by deuce4 »
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Offline Rags

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Re: Portaledge Design Discussion
« Reply #1 on: January 07, 2007, 01:09:13 pm »
John you made some really good stuff. In your portfolio there are some good pics of the ledge. Too bad TNF dumped most of it.
I am curious, maybe I missed it, how did the third party sleep in your ledge beneath the other two? Hammock?

I don't currently own a ledge but being a resourceful, mechanically inclined type, I've often looked for ways to manufacture my own gear.
I have a friend locally that has an NC mill, and we often discuss climbing gear design. We've experimented with some new nut designs.

Being an aircraft mechanic (in a previous life) I developed some insight into high strength to weight designs. Guess what this is leading to is I am thinking about making my own ledge, largely as a result of the many discussions. I've built hang Gliders also, which interestingly, incorporates many of the same considerations as the ledge. I think that ledges are unduly complex and costly.
The one feature of your design I like is the lower "fairing" / anchor point. High winds on a ledge are a bit unnerving. Only real experience with it was on the prow, spooked me good.

Now I just need an industrial stitcher, and material, and time, and ideas (which I hope are plentiful here).

Hey I know, let's make this the BWF design team thread. LOL
Be Safe, Live Long, Climb Hard!

Rick

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Re: Portaledge Design Discussion
« Reply #2 on: January 07, 2007, 02:26:36 pm »
Hi Rags-

What are you looking for: a single or double ledge? 

And yes, we made a hammock for under the Diamond Ledge.  The tubes were beefed up from 0.058 to 0.083" thick tubing (1.125 OD) for that model. Here's the pattern"


cheers
« Last Edit: January 07, 2007, 02:37:20 pm by deuce4 »
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Re: Portaledge Design Discussion
« Reply #3 on: January 07, 2007, 02:36:41 pm »
Here's some Double Ledge notes.  Nobody makes this size anymore (my favorite):













And some cut sheets:
DOUBLE LEDGE BED   (batches of 4)

1" FLAT WEBBING
(8) 2 @ 38"  **cut angle at one end**  middle triangle
(24) 6 @ 21"  **cut angle at one end**
(24) 6 @ 15"  bed

WEBBING REINFORCEMENTS (made with scraps):
small is two layers of 1" cut square and hole punched in center
large is 2" seatbelt webbing cut 4" long and hole is punched

PACKCLOTH (do not use black for main piece):
(4) 1 main piece  **2 grommets, small and large webb. reinf.
   stacked on coated side**  **long marks: 1 diagonal with
   dots, 1 along each side**
(8) 2 **flip flop pairs** sharkfins  (black is a good color)
(32 individual pieces) 4 pair large tensioners (triangles)
(16 individual pieces) 2 pair small tensioners (triangles)

BALLISTICS CLOTH
(8) 2 scuffs  (symmetrical piece)
(4) 1 *flip flop pair** scuff  (one end is narrower than other)

DOUBLE LEDGE FLY  (batches of 4)

PACKCLOTH:
(4) 1 cone
(4) 1 stuff sack  **grommet with webb. reinf. on noncoated side**

OXFORD CLOTH:
(4) 1 long narrow piece

CLAY COAT OXFORD CLOTH:
(4) 1 main body piece  **two cuts**

BALLISTICS CLOTH:
(4) 1 large scuff  **two cuts**
(4) 1 **flip flop pair** scuff with angled edge  (can be odd color)
(8) 2 collar pieces
(4) 1 **flip flop pair** chimney piece  (can be odd color)
(8) 2 small triangles  (can be odd color)

DOUBLE LEDGE HAUL BAGS (stuff sacks)  (batches of 18)

1/2" TUBULAR (or 9/16) WEBBING
(18) 1 @ 35"
(108) 6 @ 4"

1" TUBULAR WEBBING
(36) 2 @ 26"

1" FLAT WEBBING
(18) 1 @ 28"

CORDURA FABRIC
(18) 1 body piece **10 marks**

DOUBLE LEDGE HAUL BAGS (stuff sacks)  (batches of 18)

1/2" TUBULAR (or 9/16) WEBBING
(18) 1 @ 35"
(108) 6 @ 4"

1" TUBULAR WEBBING
(36) 2 @ 26"

1" FLAT WEBBING
(18) 1 @ 28"

CORDURA FABRIC
(18) 1 body piece **10 marks**

DOUBLE LEDGE FLY  (batches of 4)

PACKCLOTH:
(4) 1 cone
(4) 1 stuff sack  **grommet with webb. reinf. on noncoated side**

OXFORD CLOTH:
(4) 1 long narrow piece

CLAY COAT OXFORD CLOTH:
(4) 1 main body piece  **two cuts**

BALLISTICS CLOTH:
(4) 1 large scuff  **two cuts**
(4) 1 **flip flop pair** scuff with angled edge  (can be odd color)
(8) 2 collar pieces
(4) 1 **flip flop pair** chimney piece  (can be odd color)
(8) 2 small triangles  (can be odd color)

DOUBLE LEDGE BED   (batches of 4)

1" FLAT WEBBING
(8) 2 @ 38"  **cut angle at one end**  middle triangle
(24) 6 @ 21"  **cut angle at one end**
(24) 6 @ 15"  bed

WEBBING REINFORCEMENTS (made with scraps):
small is two layers of 1" cut square and hole punched in center
large is 2" seatbelt webbing cut 4" long and hole is punched

PACKCLOTH (do not use black for main piece):
(4) 1 main piece  **2 grommets, small and large webb. reinf.
   stacked on coated side**  **long marks: 1 diagonal with
   dots, 1 along each side**
(8) 2 **flip flop pairs** sharkfins  (black is a good color)
(32 individual pieces) 4 pair large tensioners (triangles)
(16 individual pieces) 2 pair small tensioners (triangles)

BALLISTICS CLOTH
(8) 2 scuffs  (symmetrical piece)
(4) 1 *flip flop pair** scuff  (one end is narrower than other)

DOUBLE BED HARNESS  (batches of 12)


1" FLAT WEBBING
(72) 6 @ 40"  adjuster
(72) 6 @ 4.5"  tension end
(12) 1 @ 32"  center pull
(12) 1 @ 44"  fins support  **mark center point**

**the following three lengths are tied securely in sets (making 12 total) with an overhand knot at the center point and the marks facing the inside**
**marking locations and half way point pin are located on table**
**all marks must be on the same side of webbing**

(12) 1 @ 82"  **mark center and 17" from center on each side**
(12) 1 @ 70"  **mark center and 17" from center on each side**
(12) 1 @ 63.5  **mark the offset on each, make the loose end side the center and then mark the 17" locations on both.

Making the frames is not too difficult.  Copper plumbing corners, even though they were derided mercilessly by the "competition" at the time, are perfectly adequate for a few walls (and easily replaceable).  We made our first half dozen or so ledges with copper corners, then switched to 1.375" aluminum 6061-T6 machined corners.  Tubing is 6061-T6 1.125 OD 0.058 wall thickness with two 1" OD joiners (7" long) for the side tubes.  Use stainless 3/16" rivets to rivet the joiners:DO NOT try to use cheap rivets, they will blow out and render the ledge useless in the field. Or use Epoxy metal glue.  Also, use higher grade Eyebolts for the corners, and standard 5/16" quicklinks.  All this is from memory, let me know if you need more info.

cheers


« Last Edit: January 07, 2007, 03:08:21 pm by deuce4 »
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Re: Portaledge Design Discussion
« Reply #4 on: January 07, 2007, 02:48:57 pm »
Also, double butt the tubing ends which go into the corner pieces with a short 3" piece of 1" tubing (rivet in place).

ps; this may be useful too: http://www.deuce4.net/web/PortaledgeInstructions.pdf (5MB)
« Last Edit: January 07, 2007, 02:54:57 pm by deuce4 »
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Offline Garbonzo

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Re: Portaledge Design Discussion
« Reply #5 on: January 07, 2007, 06:52:56 pm »
I was looking at Emachineshop.com as a possible way for use folks stuck using "garage technology" (as black diamond disdains it in their portaledge description) to get the spiffy corner pieces and similar hardware made up.  I'm sure that getting a decent relationship with a local machine shop makes more sense for more reasonable volumes.


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Re: Portaledge Design Discussion
« Reply #6 on: January 07, 2007, 08:18:10 pm »
Awesome John, thanx.

More info than I can use at the moment, but it's developing ideas as I type.

Gotta go get a sketch pad.
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Rick

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Re: Portaledge Design Discussion
« Reply #7 on: January 08, 2007, 11:14:26 pm »
I've never owned, sat in, or seen in person an A5 or Anker ledge, so I probably have some misconceptions.  As I understand it the main drawback to the fly with the doors was that you had to basically set it up inside the fly, and quick deployment was an issue.  Please correct me if I'm wrong.  What would be wrong with having the floor be a three sided zip on with waterproof (sort of) zippers?  You could quick deploy as usual, then with a little gymnastics you could button her up.  Vents would be necessary in some form to prevent asphyxiation...

Certainly you would want a couple inch skirt to reduce wear and keep direct runoff off of the zipper, but you they would be much less leaky to particularly wind than normal zippers.  More of a liability than they are worth?

Another thought was the buckles for the end poles.  Ever since I got a metolius crash pad I have loved the metal buckles.  It would seem like they would be an upgrade over threading the webbing through the plastic ladder locks.  Sort of thing that could be more readily done with wall hands or gloved hands.  Maybe I'm confused, is there a way to stow the ledge without undoing those buckles?

Lastly a "win-win" for garage shop trolls might be the tube door instead of the zippered door.  One of the fish criticisms of the zippered door is that to go outside to the haulbag in bad weather you expose the guts of the ledge, and yourself to the elements asopposed to just whatever body parts are necessary to access the bag.  A tube door with a cinch closure would allow the use of the tube  as protection from the elements.  The downside is that it would reduce the taughtness of the fly when closed over a zippered door, probably making it flap a lot more in the wind.  On the plus side, they are less of a PITA to sew then long zippers with all the trimming (at least I suck pretty hard at zippers).
« Last Edit: January 08, 2007, 11:19:38 pm by Garbonzo »

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Re: Portaledge Design Discussion
« Reply #8 on: January 09, 2007, 09:19:03 pm »
Duece, I have been assaulted by a hundred ideas lately. Of course, many too far-fetched. One that I'm curious about is a fully canti-levered ledge. do you know if this has been tested or tried by anyone. Weight may be the issue anywho, but getting rid of straps might be cool.
Just throwing it out there.
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Re: Portaledge Design Discussion
« Reply #9 on: January 10, 2007, 04:41:32 pm »
Bed sewing:

I'm sure that with practice sewing on seam tape on curves gets easier and faster, but for the amount I sew, straight lines are challenging enough.  For simplification I was thinking it would be plenty doable to:

1. Start with a rectangular bed.  Say 40" wide for a 48" wide ledge.  Either seam tape or roll the edges to avoid freying.
2.  For the side bar channels start with 2 rectangles (~3'x12") of ballistics, 2 of pack cloth (whatever the bed material is), seam tape the short sides or fold and stitch.
3.  Sew these onto the bed, folding the long ends under to prevent freying.
4.  Fold over and sew the top edge on the opposite face of the bed.  Bar tack at the inside corners, and run at least 2-3 lines of stitches along the length through both sides.

  Yes, I'd consider doing ALL that to avoid seam taping fricking inside curves...  Also you could cut the rectangles as slight trapezoids to shorten up the bed in the middle similar to Duece's pattern.

Spreader bar attachement:

BD does a concave pole end that locks into place.  Metolious does similar, but with an actual pole end.

Another option would be to make a T joint where the long poles couple.  For example if you make a 3-way T like Fish's 90 degree corner, the orthogonal leg could point down for popping a spreader bar onto.  Not really a cost savings, but another way.

The more I dig into all this, the more I believe ledges are no ripoff.

4130 steel tubing $2.5/foot -> $55
4 custom machined corner pieces ~$15-20 each in moderate quantities ->60
2 couplers for long side ~$10-15 each ->$30
7 yards spiffy oxford $10/yard -> $70
35' webbing at $0.30/foot -> $10
6 cam buckles at $2 each ->$12
3 yards packcloth $10/yard -> $30
1 yard ballistics, VCN, or equivalent for fly and ledge scuff guards ->$20

Total:  $302 in raw materials, not counting other stuff like cord, zippers, buckles, shipping etc.

Selling them at say $700 a pop means having to crank out about 2/day to make a moderate living.  Sell them for much more and your customers might as well go buy from BD or Metolius.   Doable, but painful once you look at liability insurance and so on.  Not to mention the monotony if that was all you made.
« Last Edit: January 16, 2007, 04:05:12 pm by Garbonzo »

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Re: Portaledge Design Discussion
« Reply #10 on: January 13, 2007, 09:30:19 am »
Some single ledge fly patterns for those in need, for the original 1996 A5 ledges:

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Re: Portaledge Design Discussion
« Reply #11 on: January 15, 2007, 09:12:37 pm »
Talking about designs, has anyone ever scene one of these "Speed Solo Ledges

http://www.speedledge.com/


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Re: Portaledge Design Discussion
« Reply #12 on: January 16, 2007, 09:19:37 am »
Hmm.  Looks interesting.   I'd like to check one of those out.

I made a traezoidal ledge in 2000 for two (or more!) people:




I took it apart for a tightrope stand a few years later:

 
« Last Edit: January 16, 2007, 11:28:14 am by deuce4 »
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Re: Portaledge Design Discussion
« Reply #13 on: January 16, 2007, 08:31:03 pm »
Duece, you've been an inspiration.  I can't keep from thinking about all the little details involved in these beasts.  It's that part of engineering that pulled me in, and has been lacking lately doing "real" engineering, which has descended into a cycle of lather, rinse, suffer, repeat.

I'm highly motivated to keep my ambitions to things that require minimal tool procurement.  At least not major tools.  Presently my wife has been unemployed for a couple months, so finances simply prevent it, and apartment life adds insult to injury.  So I'm looking at ways to crank out some ledges doing nothing more than the sewing, and for now it'll be sewing I can do on my Yamata POS.  Ugh.

Corners:
emachineshop.com can do the corners for about $15 each (about a $150 setup charge per order), minimal deburring.  Either learn to love aluminum dust, buy a tumbler, or pay another $10 each to have a fancy machine cut the corners round for me.  No sure if I should treat the raw surface with anything to minimize corrosion?  Maybe alodine (sp?) them?  Probably not worth it?

Side Couplers:
same story as the corners, but for like $10-11 per piece, still a $150 setup charge per batch.

Tubing:
Looking at aircraftspruce.com or Wicksaircraft.com for 1"x0.035" 4130 steel tubing at $2.50/foot.  It's sold in one foot increments, so either I need to cut some off to get two 3.5' pieces for a cabana length edge, or I can make the side out of one 3' and one 4' piece.  I don't think it would be an issue, and in fact I was thinking that by putting the 3' joint towards the head end it might actually be preferable, seeing as you would have the strap closer to the heavy torso than the light feet.  Comments?  Call it a feature?  "Bodycentric Support system" (tm?  BS system?) 

Fly:
Duece, in the 1996 catalog the single seam fly claims to be "patent pending".  Is it indeed patented?  If so, do you own it, or does BD, or TNF, or who?  I'm sure no one would give a shit if I made a few flys, but if I was actually making a profit (ha!) would legal thugs come and hurt me?

Probably a better plan would be to keep the ledge similar enough to a cabana size so folks could just buy the fly from BD.  BD can figure out the outsourcing to china instead of trying to compete...  Even a simply fly looks to be $100 bucks in materials, so their $250 doesn't leave a lot of room for undercutting and still making it worthwhile per hour of labor.

Fly with Floor:
Possible weak spot to come out with something, though it sounds like BD will plug the hole someday.  A zippered floor looks like a good winner.  A cinch cord would do double duty as acting as a zipper protector as well as allowing folks to leave the bottom open in light rain, and easily deploy the floor for the bad shit.  Better yet, the #5 standard pulls fit just fine, just the opposite direction.  One of each would allow the floor to be deployed from inside or out.  That or i need to found a pull with handles inside and out.

Fly front corners:
In a floored fly, there isn't anything to keep the fly from flapping around except the pole.  I'm thinking that either some 1/4" bungy, or a fastex tensioner to the front corners would make the fly drum tight over a reasonable range of rock angles.  On real slab your just gonna be hosed no matter what.  The floor would still flap around, but I haven't come up with anything to help that yet.

Haul bag:
Ballistics is good stuff, but I'm thinking it would be worth it to put a small skirt of 2" seat belt webbing around the base where the worst of the wear occurs.  Also a thick VCN bottom is warranted with the pokier chrome moly tubes.  I see a straight forward way to sew a tube, invert to sew on the 2" seatbelt webbing, invert again to sew on a thick VCN bottom, and invert again for final use.  PITA, but doable with a POS machine.

Ledge only cost looks like:

4130 steel tubing $2.5/foot -> $55
4 custom machined corner pieces ~$15-20 each in moderate quantities ->$80
2 couplers for long side ~$10-15 each ->$30
35' webbing at $0.15/foot -> $6
6 cam buckles at $2 each ->$12
3 yards packcloth $5/yard -> $15
1 yard ballistics, VCN, or equivalent for haulbag and ledge scuff guards ->$12
Buckles, seam tape, etc:  $10'ish
Total materials:  $220

Labor could be gotten down to roughly 6-8 hours, probably a lot faster if I could sew faster than I climb and if I had a bar tacker for all those straps...  So I could actually make my money back and justify turning the profits into a  better shop.  Now I have to scrounge up about a kilobuck to get some machined parts procured.  Still trying to figure out how to swing the industrial sewing machine too.

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Re: Portaledge Design Discussion
« Reply #14 on: January 17, 2007, 09:45:16 am »
Garbonzo-

You are on the right track.  A couple suggestions: go with the 1.125 " OD 6061-T6 tubing.  It is often cheaper in small quantities becuase it is the main size tubing for hang-gliding down tubes.  Check with some hang gliding shops, you should be able to find it a bit cheaper than your quote above.  The thickness of the 1.125" tubing specified is 0.058" wall.  This makes a 1" joiner easy and simple, just straight tubing no machining necessary.

A note on corners.  After milling the 1.125 " hole, you will want the hole reamed to a few thousands over, so the fit is not too tight, and not too loose. 

The floored fly with the pole doesn't seem to flap.  Plus, what ends up happening is that all the wet socks, extra food bags, etc get thrown down below the ledge (highly convienient!) which weights  down the floor to prevent flapping as well.

Keep at it!

cheers

ps: there are no patents currently active on the single seam. 

pss: you might end up with more than 8 hours into it, but it is fun work (to me anyway).
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Re: Portaledge Design Discussion
« Reply #15 on: February 11, 2007, 11:56:40 pm »
Figured out something about flys today.  Humans need air.  I'm working on a fly for my bastardized fish single to double conversion.  It's a scaled version of Duece's A5 alpine double pattern to fit the 78x"45" frame I've ginned up.  I figured that waterproof is good, so why not use those fancy water resistance zippers on the fly doors?  It occurred to me as I'm sewing on the third zipper that once I've seam sealed the thing I'll be leaving a couple grommet holes and a small hole at the top of the door as the ONLY ventilation points.  El Sucko!  Bad idea to design your ledge so that the user can readily die from normal use...  Normal zippers still don't let tons of air through, but much more than these things.  Add to that the $2/foot cost for 28' of fancy waterproof zipper, and it really ain't looking all that great.

Good news is that after putting in >20' of zipper I'm finally getting sorta quick and not screwing up near as much.  Normal zipper would be easier, as the waterproof stuff is sewed in upside down for normal.

Also, cutting a 16'x5' piece of slippery fabric on a 2.5'x6' table ain't much fun.  Lots of origami.  Lots of sliding cutting mats inside folds for making cuts, etc.  I ended up redrawing things in autocad to more easily make measurements (having already used fancy trig to determine all the news angles and lengths).  For example the door cuts I make marks along the 30" foldline and cut the doors in two goes.  Ugh.

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Re: Portaledge Design Discussion
« Reply #16 on: July 08, 2009, 12:06:40 am »
Engineers in action.
Well, they WERE in action. Honest!

Offline Caz

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Re: Portaledge Design Discussion
« Reply #17 on: July 13, 2009, 01:35:07 pm »
The Re Animator strikes again!!!


hahaha   ;)
I do this for fun...

Offline johnmac

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Re: Portaledge Design Discussion
« Reply #18 on: July 13, 2009, 03:47:16 pm »
If you need any detailed photos let me know as I have an A5 double ledge and could easily take some pics for you.

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Re: Portaledge Design Discussion
« Reply #19 on: January 07, 2011, 08:19:33 pm »
I'm curious if carbon fiber poles would be appropriate to try for an ultralight ledge.  In poking around I've found prices on probably carbon fiber poles that would be a bit more than titanium, but half the weight (and only 1/3 the weight of aluminum or Chrome Moly).  My fear is that they would not fail gracefully like Chome Moly does (i.e. bends quite a bit before kinking).  Anyone have a more hands on feel for suitability?

For example 1 1/8"x0.058" carbon fiber tubing runs 0.13 lbs/foot, 6061 of similar dimensions runs 0.23 lbs/foot, 1"x0.036" titanium runs 0.21 lbs/ft and 1"x0.035" 4130 runs 0.36 lbs/foot (Russ uses 7/8" which is 0.31 lbs/foot).

So just the tubing for a double cabana sized ledge (22 linear feet, not counting double butting, joiners, etc):
Carbon Fiber: 2.86 lbs
6061: 5.06
Titanium: 4.62
4130: 7.92

Not sure of exactly the best tub to use with titanium or carbon fiber...

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Re: Portaledge Design Discussion
« Reply #20 on: February 14, 2011, 10:42:26 am »
Current Project:  Carbon Fiber Cabana style ledge

Corners:

Just ordered up a batch of machined 6061 corners, enough for 7 ledges (might as well, given the setup charges):



Tubing is coming from http://www.rockwestcomposites.com/, going with 1.00 ID x 0.065" thickness, going to be just shy of $500 for just tubing for 1 ledge.  I am glad my wife is this indulgent (she's letting me burn the Xmas bonus on my hobbies again).

Still working on the side joiners, getting quotes.  Worst case scenario is I waste an evening with sandpaper whittling down 1.00" OD x 0.125" to 0.99 OD x0.12" tubing...

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Re: Portaledge Design Discussion
« Reply #21 on: February 14, 2011, 11:17:18 am »
Don't design a new ledge!

Buy my fish ledge!







No really, that is a cool idea.  I saw a ledge for sale recently with a custom made titanium frame.  Does Carbonfiber have a strong enough flex?

Offline Garbonzo

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Re: Portaledge Design Discussion
« Reply #22 on: February 14, 2011, 03:10:28 pm »
Already have a Fish ledge (technically I own a second one too, at least until the deadbeat I sold it to ponies up).

Already have a homemade double ledge (1" 4130 frame).

I want a uber lightweight ledge.  Switching to Carbon fiber will cut out 5 lbs of frame weight alone.  The new corners will cut out nearly another 1 lb compared to the stainless marine railings i have been using.  Besides, I have 2 TNF/A5 ledge flys, so I want to make use of those.  I learned a great deal from making my double ledge that should shave more weight:

1.  Only put bed tensioners on one end, saving lots of excess ballistics, straps, buckles, etc.  Just need one stripe of burly webbing for a rash guard (much less sewing too).

2.  Angle the fin MUCH more than you would think.  For comfort your feet only need half what your torso does.  Mine had 27" for torso, and 21" for feet.  Should have done more like 31" and 17".

3.  For one-off ledges cut the tubing an inch large on the ends.  Once the bed is sewn start whittling the end tubes down till things work out nice.  I had a bit of a slop fit and had to do a lot of seam ripping to get things tight enough.  Another lesson is to spend some quality time in the ledge to see how much the bed will stretch before making final decisions, as I should have tightened my up width wise maybe another 1/2".

Offline johnmac

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Re: Portaledge Design Discussion
« Reply #23 on: February 15, 2011, 06:52:13 am »
Maybe email luke and chat with him about designs. Some of the stuff that he is doing is pretty impressive and between the two of you, you might be able to make great strides in design!


http://www.mountainproject.com/v/big_wall_and_aid_climbing/portaledge_designs/107008563

Offline Garbonzo

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Re: Portaledge Design Discussion
« Reply #24 on: February 15, 2011, 05:13:45 pm »
We're chatting.  Looks like he's going to make a business venture of sorts out of it.  My motives are almost entirely hobby grade.

Offline hoipolloi

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Re: Portaledge Design Discussion
« Reply #25 on: February 16, 2011, 08:31:55 am »
that is awesome!  Talented minds at work.  Keep us informed!

Offline johnmac

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Re: Portaledge Design Discussion
« Reply #26 on: February 16, 2011, 12:07:03 pm »
That's great that you and Luke are in touch. Hopefully, you can help each other.

There must be an alternative out there rather than heavy ledges! Personally, I don't like Fish ledges. I just don't like the tangle of webbing. My fav ledge is still the old A5 Double, but at some stage I'm going to have to replace it. I've been looking for a alpine fly for it for years, and each time I either get auctioned out or the lead I'm following goes no where.

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Re: Portaledge Design Discussion
« Reply #27 on: February 16, 2011, 05:12:13 pm »
Tom Kaspar had a Carbon Fiber ledge. He used it on Bermuda Dunes. From what I heard from Pete, it didn't fare so well.
« Last Edit: February 16, 2011, 05:36:06 pm by skully »

Offline Garbonzo

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Re: Portaledge Design Discussion
« Reply #28 on: February 16, 2011, 05:47:39 pm »
There has definately been a drive to overbuild some softgoods recently.  Metolius for example sells a rope bag out of some way burly 1000+ denier cordura like stuff, which is fine, but weight a good pound.  For a rope bag.

Similarly the BD ledge comes in at 18 lbs or so, before you get to the fly...

The trouble is that we, the consumer, tend to err on the burly side all other things being equal.  Despite 400d pack cloth being plenty for A5 ledges of yore and Fish ledges of today, we had BD using 2 layers of it, and metolius using 1000D stuff.

Luke is on the track, playing with Titanium (but getting no buyers on his single).  He is also making noise on CF stuff if you look carefully at his pictures.

So where does the weight come from on a BD ledge?

Frame:
22' 6061 tubing @0.23 lbs/ft is only 5 lbs of main tubing.
~1 lb for corners
~0.8 lbs for joiners and double butting
~0.5 lb for the spreader bar (vague recollection for hefting one a few years back)
~1 lbs for suspension buckles.
~1 lbs for quick links, bolt hangers, and bolts in the corners (total wag)
~1/2 lb for bungy cord (total wag)
So ~10 lbs for the metal bits.  Going to carbon fiber only shave a couple pounds off this

Bed:
5 square yards of 420d fabric, times double thickness, times 8 oz/square yard is 5 lbs
Another 2 lbs for rash guards, fines, pockets, tensioners, etc?  Total wag here.
7 lbs for the bed

Suspension:
 80' 1" thin flat webbing is roughly 1.5 lbs, I'd have to weight some to be sure.
Monkey paw, 2 oz?  I never understood the need for this?

I don't know if they include the haul bag in their 19 lbs 13 oz?  So perhaps that is where the other 1.5 lbs is?  Their haul bag is huge, yet strangely not very burly...

So what I see as low hanging fruit:
1.  Scale the ledge down, as tube weight and fabric weight both immediately drop.  If I didn't have two cabana flys I got for cheap...

2.  Single layer bed material.  I'm giving the 500d spectra ripstop Luke is using a shot.  it looks to be a good compromise between simple pack cloth and 2 layers of ripstop overkill.  Too bad it is black...

3.  More machining on corners like Metolius (not square blocks), and eliminate the bolts, hangers, and quicklinks.  I like the Fish style webbing corner suspension, but do like the quicklink decluster advantage (Fish style suspension only works if you can use continuous bungy, i.e. folding funky like his or breaking the end poles in half).

4.  Minimized the rashguards.  I like the single wide strip of heavy weight webbing on the wall side.  i don't see the need for fully reinforcing with ballistics.  Am I missing something here?

5.  Lighter frame tubes comes in low on my list, and is a matter of throwing money at the problem (the last bastion of a bad engineer).

Offline johnmac

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Re: Portaledge Design Discussion
« Reply #29 on: February 16, 2011, 08:25:15 pm »
You're got some great ideas there! And thanks for the analysis on the BD ledge.

Basically the BD ledge is just total overkill. I was really interested in it when I saw it online but as soon as I looked at it in the shop and saw how heavy it was, I figured I would never use it. The difference in weight between the A5 and BD is just too much.

I'm surprised no one has purchased Luke's single ledge. It looks great. If I had the money I'd buy it. Unfortunately, my wife is in the process of losing her job (Operating Room Clinical RN) due to the economy. Centura Health just isn't making enough money so we trying to bank it away while we can.