I recently bought a Jam2 as my 3 season pack and I am very happy with my purchase. With my 3 season pack loads, it is incredibly comfortable. In a few weekends I am gunning for a 15 hour winter alpine climb that I want to do as fast and as light as possible. Unfortunately with current snow conditions and an approaching winter storm that is going to dump over a foot of snow in the valleys I have to bring snowshoes along with my ice axe and crampons along with the rest of my winter essentials. I guess what I am looking to do is to add some kind of plastic sheet to supplement the foam support to help carry the weight alittle better. My summer base weight with this pack is 10 lbs but with a winter trip like this I am pushing 20-25 which I find to push the limits of comfort for me on this pack. Does anyone have any good ideas?

Jonathan, 2 ideas come to mind. If you are using an inflatable pad, like a Thermarest, you can insert it like a pipe inside of the pack. You do this with the valve open, then after you pack your stuff into the void, you blow air into the mattress to make it firm and then close the valve.

The other idea is a corrugated plastic sheet cut to fit. The same stuff used for signs. If you need to curve it to fit your back you can insert some wire into a few of the corrugations to give it some shape.

The first idea is something I do in my Jam. The second idea is one I read about on the forums, but have never tried. You could also sew a couple of channels for aluminum stays, I suppose.

Edited by ericnoble on 03/16/2007 08:15:40 MDT.

The plastic sheet is a great idea. Where can you pick somthing like that up?

I seem to recall seeing it at Officemax or Staples. Of course, during an election it can be found by the side of the road, if you don't mind some dudes face staring at you from inside your pack. You know... I just can't shake the feeling that I'm being watched :).

Edited by ericnoble on 03/16/2007 08:53:12 MDT.

Why didn't I know that, I work for the Staples home office?? The brain is just not working today. I will check it out today at lunch. Thanks for your help.

It just occurred to me that you could probably get the stuff from a sign shop and have them print whatever you want on it. Like first aid info or knot diagrams, etc. It might also serve as a splint, or a wind screen if you glued mylar to it. It should also be a good stake holder.

I second the sign idea, I got it off someone here on the forum and it works great. I found a old political sign that had been lying on the ground all winter long and it was still in great shape, its like a plastic version of corugated cardboard. Super light too...

Art supply stores have the same material.

Reduce, Re-use, Recycle.

Jonathan,
An alternative is to not use the hipbelt for support, but only for stability. Or remove it entirely if that is possible. 25 pounds is not too much to carry comfortably without a hip belt, IME. That will save the weight of the belt and the frame sheet. However, I have used the same corregated plastic material as a frame when needed. The edges will crush in time, and if it gets creased, its days are numbered, but you can usually get a few days of good performance out of one.

Oooh Eric, I really like the corrugated plastic idea (especially since it's free and easy to work with). It would probably do double duty as a sit pad as well.

I'm coming into this a bit late but I may be "that guy" who posted some pics of a frame sheet I was making. For the most part it's just a copy of the go-lite system but using easy to find corrugated plastoc boad. I use brass tubes in mine as the alu. ones I could find just flexed to much.

They aren't that hard to make. One thing I found helpfull is to round the edges and wrap in electrical tape to prevent it cutting into your pack.

I read someone saying it could be used as a sit pad but I would say don't try it unless your going to use something very stiff

Joe F

Joe,
Are you just running rods down in between the corrigations in the plastic? or are you attaching them to the outside somehow..

Looks really good, how many are you using?

ps. I used my new pack on a winter trip last weekend and it worked great with the plastic board. Had it pretty fully loaded and no problems at all. Also threw the pack under my legs at night for more insulation, that material seems to hold up just fine so far.

Edited by EricP on 03/29/2007 18:07:40 MDT.

I'm just running 3 tubes between the openings in the plastic. The electrical tap prevents them from sliding out but once you make the bends they won't move.

How did you shape the plastic like that? Your frame looks awesome.

David

Once you have the rods slid into the sheet it's just a matter of taking your time and bending it either off the edge or a table or your knee. You can also a ruler over it at the edge of a table help hold it at first.

The key is do it slow but the whole thing should take about 10 min max.

Joe F

When you use a frame like this made from a sign, is padding still needed behind it for comfort? If so, I would be concerned about the additional interior space that is now taken by the sign. Great idea though, and I may try this may give me the confidence to go for the MLD Zip now.

I've not needed any padding when using the plastic frame sheet in my pack. I guess depending on the weight you have it might be needed.

JFF

If you don't want to use the metal tubes or don't have acces to them. You can shape this stuff over an electric stove hotplate.
Disclaimer: Make sure you have enough to make more as its hit and miss with using too much heat. Oh and don't forget the other various dangers of doing this type of thing.
I made some prototype motorcycle backprotectors using the sign plastic combined with various other materials.

Tape the perimeter edges so it doesn't tear your pack.