Lighter Carbon Back Stay – version 2

Kevin's Carbon Fiber Pack Stay:

The pack Stay came by UPS yesterday.

Today I have spent a little time working out my first version to attach a Pack Bag to the Carbon Fiber Stay. Not everything you see made it to the next version. I expect to go through several versions before I get something I really like.

Working on a the Hip Belt – Shoulder Strap attachment.

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Looking forward to seeing where you go from here Bill.

As usual, you definitely think outside the box and I'm waiting for the next round of photos and updates!

THANKS!!
Kevin

Yep, looks real good. I'm seeing now the benefit to having the carbon wrap the waist aswell. I'm guessing that this will truly transfer ALL the weight to the hips…I think you will have to rely much less on the tightness of the hipbelt with this system…a good thing!

Friday, I have now had Kevin's Carbon Fiber Stay 2 days. I was just a bit excited when I saw it and went to work to get a few ideas worked out.

I have a Pack Bag modified to work with the Stay. I am real close to packing up it up and taking my first walk with it.

I can now take a short break and reflect a bit about Kevin's Carbon Fiber Stay. The weight is as Kevin has posted, about 5.04 ounces. I will not speak about the construction or the Carbon Fiber. I just don't know much about Carbon Fiber and nothing about its construction technique. I am impressed with its construction and strength. Don't tell Kevin but I did try and break the Stay. Using only hand strength I could not begin to even bend the Carbon Fiber Stay let alone break it.

It turned out easy to modify a pack I was working on to connect it to the Carbon Fiber Stay. The pictures show where I am with the Stay / Pack attachment. Some of what you will see in the pictures are my card stock patterns. I will finish the Hip Belt this afternoon.

Note: The Pack Bag is just a bag I was working on and is not any attempt to make a very light Pack Bag, yet. Just because someone will ask – the weight of the Pack Bag / Carbon Fiber Stay as you see it in the photo is 13.6 ounces.

8. Carbon Fiber Stay next to the pack / sleeve for the Carbon Fiber Stay.

9. Carbon Fiber Stay installed on Pack Bag.

I am very excited about the potential of this stay. Really awesome work, Kevin. I am watching this thread closely.

Its ALL in Bills hands now to work his magic !!
Can't wait to see what he comes up with and then has a chance to test it out.

Bill, looking good. I hope you have a great weekend!

Kevin

I finished the pack bag for the Carbon Fiber Stay, loaded it up with 20 pounds of stuff and went for a 2 mile walk. I needed a way to get a little air between my back and the pack bag so I tied in two of my ThermoPlastic Pillows. Then I went for another 2 mile walk. The Pillows worked well and also gave me just a bit of cushion. The Pack / Carbon Fiber Stay carries the 20 pounds without any problem.

I am going to start on a new pack bag using this one as a pattern. I will make a few non-Stay related changes and see how it turns out. With the new bag I will increase the bag weight until I get it up to 35 or 40 pounds and see how that goes.

I haven't had to make any changes the Stay yet.

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These may be the last pictures I post for awhile.

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I think I have roughed in all the changes to the pack bag that I am going to make. I have backed off the pack weight to 15 pounds for a few days. I carried it for 4 miles today. The Carbon Fiber Stay is working well and has all but disappeared into the pack bag material. The addition of the two "TP Pillows" give me a nice window of air space between the pack bag and my back.

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I will take the next few days and work on my hike gear list. When that is finished I will see if it will all go into this Bag. If it all fits I will start on a new pack bag.

During this time I will continue to carry the first pack bag and increase the weight till it is 5 pounds over what I think I will be carrying on my hike.

Bill,
Great news so far! Thanks for posting and testing the stay!

Kevin

I am wondering if connecting the shoulder straps directly to the frame can help in better load carrying.

Huzefa,
Good question ….. and this is something that I had been thinking about as well.
I haven't tried it as I'm trying to keep it simple to start and figured just adding the carbon stay to an existing pack would be a easy way to start. I have shipped out both of my new carbon stays to others to test out so I don't have anything to play with unless I make another one.

Kevin

Bill,
Any progress to report on the new pack ????
DEFINITELY looking forward to seeing what you have come up with and what you think of the stay so far.

Thanks
Kevin

Hi Kevin,

Funny this should come up at this time.

Over the weekend I made a new pack bag for your Carbon Fiber Stay. It was more or less the same design as the other bag I had been modifying for the stay.

The lighter material ( the other bag was mostly two or three layers from my changes) had a problem with the edges of the Stay. The edge cut the material and the thread. I am now trying to work around that by using double the material where it comes in contact with the Stay and not sewing it so close. I am also going to put a piece of tape on the Stay edges to soften the contact points with the material. This is not a big deal and should not add very much extra weight to the pack bag.

Bill,
Looking forward to seeing the new bag !!

On the stay, you can sand down any sharp edges on the carbon using standard sand paper. Applying tape to the carbon should help as well.

Kevin

I would like to see an upward-tapered (bigger at top) stay for v5. The top part should have enough surface for attaching shoulder straps directly. Could even have slots?

Ideas for pack with v5 stay:

>Durable Cuben fiber material for pack body and shoulder straps
>Roll top 100% waterproof. valve attached for inflation/deflation would be nice.
>Replace heavy webbing/buckles with 2.5mm urethane coated Spectra/ Lineloc WSR / 9/16" Climb Spec Nylon Webbing
>Upward tapered (narrow bottom, wide top) for high center of gravity
>Vertical divider (see Aarn packs) to bring loser closer to back.
>no padding in backpanel/shoulder straps. Nice padded hipbelt
>Pocket for sleeping pad behind the stay.
(Idea is that load is completely transferred to the back and hips so padding is not necessary for shoulder straps. Inflatable sleeping pad forms a reservoir of cushion behind the stay so padding MAY not be necessary for backpanel. Experiment required)

>Shoulder straps should freely pass behind the hipbelt and should connect to each other.
(two advantages 1> both shoulder straps are equally adjusted when only one of them is tightened. 2>freedom of movement when bending to the sides)

>Load lifters: only if the stay extends past the shoulders; the load lifters should then be attached to the end of the stay.

>No side pockets. They only lower center of gravity and add weight.
> A high rear mesh pocket could be useful for wet shelter/clothing.

> other features
Sternum Strap, dual daisy chains, axe/trekking pole strap, haul loop, variable compression system (see ULA Amp), compression straps which can mate on the sides (skis) or across the front (snowshoes), big hipbelt pockets.

Huzefa,
If I only had the time …..

I had wanted to make a cuben pack to try it out with this stay but I really need to make another cuben shelter for the summer/fall and that will be taking up most of my time in the next few months.

I think you have some very interesting ideas here. Why don't you make this bag and I will make sure that we test it with the carbon stay!

Kevin

Hello Kevin,
I just saw this thread. It looks very interesting. In my view you need some moveable adjustment. Would it be possible to make a minimal wing version and 2 curved more flexible wing extensions and attach them together in some variable way. For example a big patch of velcro. Now the wing extensions could be shaped and positioned so their top edges perfectly follow the crest of the users hips for about 100mm to the point at the front of the hips where the crest falls away. When a non padded flexible hip belt is attached to the top edge and front of this structure it would pull in and cradle the hips perfectly. I am imagining the extensions being small, only big enough for fine adjustment.
Note this has some parallels to, but might be a big improvement on an Aarn belt.

Thanks Kevin, I would love to make a pack for this stay. Right now I am playing with some 1.5oz cuben for another project. Very cool stuff! But it isnt puncture proof. With some pressure I can poke a pen tip through. I think puncture proofness isnt really required or can be expected from SUL gear. What is important is that punctures/tears donot spread and this weight of cuben is very good at that.

I have limited quantity of the fabric and can order more for the pack only next month.

Hi Derek,

>Would it be possible to make a minimal wing version and 2 curved more flexible wing extensions and attach them together in some variable way.

Why? Kevin says in an earlier post >Yes, the wings are flexable and they flex more as you get closer to the tips.>

>Now the wing extensions could be shaped and positioned so their top edges perfectly follow the crest of the users hips for about 100mm to the point at the front of the hips where the crest falls away.
>>Note this has some parallels to, but might be a big improvement on an Aarn belt.

note that both mchale and Aarn donot use any stiffeners in the belt. Best to keep carbon wings to minimum and as flexible as possible.

You will not find plastic stiffeners in our hip belts either. The belts wrap so effectively that they create their own firm structure. Belt stiffeners are the current hallmark of high-tech packs. It is really too bad real people are not as insensitive as mannequins because we think the new crop of belts on the market are a step backward in comfort. mchale packs

I am not sure can one improve on aarn hipbelt. There is so much attention to the details on aarn packs that it is mind boggling. Lately, I have been drooling over aarn packs. Now if they made packs using cuben fiber and pack weighed under a pound… but thats not going to happen.

Kevin,

Similar idea can be used here:

Huzefa,
Aarn belts have wings that are attached at the stay right by the spine with a big Velcro patch for maximal adjustment.
I believe the aim is to bring the curved edge of the stiff part of the belt in line with the ischial crest. The part of the belt infront is made from flexible mesh. I have not taken a belt apart to see why it is stiff but I assure you it is thin and stiff
Under heavy load I can feel the stiff part of the belt at the back distorting. I think it must improve things for a really stiff (in elevation only) carbon stay to carry the load round to the sides. I think you would then not need the belt so tight to get good load transfer. This would be more comfortable. I think a CF shape like Kevins is a probably lighter way to carry load forwards. I personally would still add front pockets to balance the load front to back and give access during walking.
Arrn is just sending me a pre production MM 55 to try.
As I see it this carbon stay would be most help for really heavy loads. But might well help the whole range.

Without the adjustable wing extensions we are in DIY land where people have to cut and file the CF stay to their own hips and then buy a new stay if their waist increases at Xmas.

I understand what you are saying.

I have an idea which can eliminate the need of velcro: elastic 3D mesh. I am not sure whether aarn uses "elastic" 3D mesh but this would be perfect material for hipbelt, shoulder straps, and back panel. Elastic would automould to any hip shape. What is important is dual buckles. This allows adjustment of top and bottom separately eliminating the distorting you speak of. Also 3D mesh will give great ventilation, so it is MUCH better alternative to cuben straps and CCF hipbelt.

Thinking about this CF stay. It is totally rigid and people's hips, (especially but not only, women) rock their hips as they walk. Most packs either specifically have a joint between the hip belt and the back stays or are so poorly fixed that there is no problem. This inverted T stay is either going to restrict hip movement or make the pack tend to swing from side with the hips.

Huzefa,
On the Natural balance Aarn uses 3D mesh in different thicknesses for:
the shoulder straps,
the surface between the pack and the user's back just for ventilation
and the hip belt from hip crest to hip crest across the belly, infront of the stiffer part of the hipbelt from hip crest round the back to the other hip crest. His hip belt has a fabric hinge at the back so the natural hip movement is allowed without moving the pack

Derek, you have a point.

Kevin, for V5 why not make stay and hip portion separate and then connect them with a pivot?

Did anything ever come from this? I would be very interested in purchasing one of these stays!!

It was good reading through this thread again. I've been doing longer trips in the winter and with the heavier loads, this stay appeals to me even more. I communicated with Kevin via e-mail a few days ago – he has been very busy at work so I am not sure if he made any more progress. Of course, I'll let him answer…