Tyvek has a very low melting point. It might not be easy to get the dessicant hot enough to regenerate in a tyvek bag. PTFE-coated nylon, like e-vent, would be better, but still nowhere near stove-exhaust temperatures. That's why I chose an aluminum tube. Also, the hotter the dessicant the less moisture it will take up from steam in the stove gasses (burning butane and propane produces water vapor).

Also, the tube made it easy to pump outside air, from a poly bag, through the dessicant and into the sleeping bag (I cut the tube so it was open at both ends).

A clever design could probably get around these minor obstacles, though. A fabric bag might work for your DAM.

Colin,

What orientation to the stove, distance, and heating duration did you find best regenerated your desiccant?

I made a wire cradle that kept the dessicant tube out of the flame, in the path of the hot exhaust flowing up around the sides of my little aluminum pot (which I still use; It's one of my favorite pieces of gear. It's the bottom half of a 2-liter Japanese beer can). My windscreen had two holes for the ends of the tube, so the ends stuck out in the cool air. I left it there until the water in the pot boiled. Then I took the tube out, capped it, and put it away until it was time to pump up the sleeping bag.

I wasn't really happy with the way it looked or with the field utility in the end so I never took pictures and the materials got recycled (the down and the hardware, anyway). I still have the pencil sketches which I can scan and post if that's useful to anyone.

@Huzefa
With all the neccessary respect but did you ever finished one of your projects?

I'm reading a lot projects you have started, recently. Some sound pretty fanciful.
One the other hand you are planning a trip to the Everest, based on those projects. Due to the fact that i have never seen a finished myog-project i would strongly advice to finish and test it in "real" conditions, like the ones you will be faced with at the Everest. This will help you to learn more about fabrics and hiking itself. Then you will realize that thinks are sometimes different ;). It will also improve your myog-skills.
Ever made a good double lap seam with silnylon?
http://www.hilleberg.se/images/allmin1.jpg

Just correct me if I'm wrong.

Oliver

Hi Oliver. You are right. I havent finished any of the projects yet.

All issues with DAM design are solved. But I am thinking of getting lightest silk directly from China or Thailand, when I go there next time(for business work). So the project is postponed because of that.

For other projects I am taking my time till the ideas develop into concrete designs. Take sub-2 lb tent idea for example, the plans were going fine. But I realised that it has to be pretty small and low profile in order to balance the lenght of fabric between two poles, keep the side at steep angle and shed wind. So I wasnt satisfied with the compromise. Then Mike's comments pushed me to consider a single pole design. I digged into hex, four side pyramids, alphamid, and two pole designs. So I cant order stuff until I have a design I am satisfied with and have finish all calculations.

You might be interested in the my two pole tent (based on MSR twin sisters) drawings:
http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/13249/index.html

Most of the people here are hiking since many years. They started with traditional heavy weight gear and slowly replaced their gear with light wight stuff. They have have bought and sold numbers of backpacks, sleeping bags, tents and other gear - In that process they have built a suitable system for themselves. Many are now converted to UL and some are even SUL.

I started hiking about 10 months back. Fortunately I found BPL very soon. I remember how excited I was when I learned about ultralight gear. I spent a lot of time trying to deciding what gear to buy. If I had money I would have spent it. But I am college student and my parents dont think much about hiking. And hiking here doesnt require anything more then water, food and a small pack. So I decided just to keep reading and keeping myself updated.

Take a look at my Everest base camp SUL gearlist in the gearlist forum. It is a result of brainstorming and not exprimentation. I know I have to test it to find out if it will work but I am really happy how it has turned out.

MYOG ideas give me great satisfaction and allow me to customize. Eg. if I buy shangri la 2 it may not fit with my trekking pole. MYOG allows me to make a tent that will fit perfectly with my trekking pole.

The dual WPB/VB jacket project which uses propore, cordura and silnylon is also postponed till I finish my tent design so that I can buy materials for both together from quest outfitters.

But yes I can practice sewing a nylon jacket in the meanwhile.

>Ever made a good double lap seam with silnylon?
http://www.hilleberg.se/images/allmin1.jpg

no. But it looks pretty tough seem. I was planning to use french seam for my gear. Any advice on seams?

A French seam you use when you don't wanna see the seam or when you have transparent fabrics. This is not the best seam for a tent. Even for seams with less loads i wouldn't use this seams. There i would use a folded or welted seam.
For high load seams i would use this lapped-fell/ flat-felled seam/double lapped seams. Sry found several translations for this one.


Greetings from Germany
Oliver

> Ever made a good double lap seam with silnylon?
> http://www.hilleberg.se/images/allmin1.jpg

I don't know how you get to that pic, but I don't believe it anyhow. Not exactly as it is shown, anyhow.

Cheers

Why do you not believe it Ô.o?

I've googled a bit and found this on the "english"web.
http://www.garmento.org/751Astitchesandseams/LSc.htm
http://books.google.de/books?id=BKTuTXrXQu0C&pg=PA482&vq=gbs_search_s&sig=hwy8DDtOwSc1XBI9GONnXHF7vd4
http://www.the-needles-eye.com/NewReleases/35800/35800DNUB/35800DNUB9.htm

As you see in industrial use there are special machines that only sew this LSC seam. But it works also on home sewing maschine. But it would need some training. Silnylon won't make it easier ^^

If you still don't believe it, than I can grab my machine and make a sample and photos of it. I have a normal domestic machine without any special folding attachment. Not even a twin needle.

Roger here you find all kind of seams:
www.amefird.com/seam_type_matrix_flyer2.pdf

Oliver

Edited by Snuffy on 05/02/2008 06:47:49 MDT.

Roger,

it might be a realistic picture for an industrial sewing machine not a domestic one.

Pfaff do produce a foot that is designed to help with felling seams on a 'domestic' machine by folding fabric as you go.

I've looked at seams on commercial tents and in general it does suggest that they were sewn with a twin-needle. It's very difficult to sew perfectly parallel seams.

Is this the correct double lap seam?

Edited by huzefa on 05/02/2008 11:06:19 MDT.

Why don't I believe it (as it is shown EXACTLY)?

Because I have spent maybe 10+ years making UL tents out of silnylon and other UL gear out of a range of fabrics. Trying to make that EXACT seam in a UL fabric like silnylon is a nightmare - especially on curved edges.

Yes, I do have seaming feet for at least one of my sewing machines. You can make it work with some stiffer fabrics at low speed. But dimensional stability is not great.

However, if you make the seam in a two-step process as Huzefa shows, then it is easy. But the original pic does not show the first line of stitching, and it is that lack which prompted my disbelief for UL tent fabric.

Cheers

Edited by rcaffin on 05/02/2008 16:30:07 MDT.

Well you are right on (narrow) curved shapes its hard. But when you straight edges it works good.
At the moment i am sewing my second lavvu/tipi/teepee and i am using this seam.
Some glue may also help (for the beginning)


Oliver