Sunday, April 13, 2014

Backpacking Pot Cozy V3.0

I got a new pot that would provide more food in my belly, and take less room in my pack. So it was back to the drawing board to design a new cozy for it.

As the title suggests this is my third cozy. The first was designed to fit my MSR Titan Kettle. It was made of the same light cotton duck you see on this one. After hiking the Georgia section of the AT, I felt I needed to cut down on weight. I adopted my Snow Peak 600ml cup as a pot, and used some lighter cotton material. After 1300 more trail miles, I felt the pot was a little small to feed my hiker hunger, the fuel canister didn't fit inside, and that cotton started to wear through.

Design and materials after the break ...

Cozys allow backpackers to save fuel by finishing the cooking process in a cozy. For instance the excellent web site in their "Fuel Saver Quinoa" suggests boiling quinoa for 5 minutes, then placing the pot in a cozy for 15 minutes. A big savings over simmering for 20 minutes!

I decided to go back to the ripstop cotton duck. It's relatively heavy, but tough. I chose cotton, because I take the pot right off the flame and slip it into the cozy, and I don't want it to melt. The pattern is a tropical-themed cammy.

I still had some Insul-Bright for insulation. It's a hollow polyester fiber with a metallized film backing. The backing resists radiant heat loss, the fiber resists conduction. The metallized side goes towards the heat source.

I made a pattern by measuring the circumferences of the lid and the pot. The sides of this lid stick out quite a bit from the sides of the pot, so I decided to make the outside piece the size of the lid's circumference. The inside piece is the circumference of the pot, and its height is the distance between the pot's bottom and the bottom lip of the lid. That way the insulation fits in under the lid. I used the lid's circumference give me the for the bottom piece. Then I added 5/8" for all seams ...

Basically, I repeated the same design I used on the first two versions. The slit down the side worked great for allowing me to slip the pot into the cozy with the handles deployed. I reduced the number of clasps from two to one, increased the size of the clasp, and I moved it down into the center of the slit. I never used both clasps on the last mod, they were a pain to manipulate, and moving it down provides easy access between the handles.

I also copied the previous designs in that I put the Insul-Brite around the sides and on the bottom. In previous versions, that insulation tended to bunch up when washed. This time, when I sewed the insulation to the inside piece of duck, I ran stitches across the length. In effect quilting it. Then I stitched that to the outside piece so that the quilting doesn't go all the way thru. Did the same with the bottom pieces. The quilting might reduce thermal efficiency a bit, but I suspect it'll be minimal.

It came out to 1.9 ozs, up from V2 which was 1 oz.  I suspect it will hold up to the next 867 miles, and more!

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