[pct-l] shirt fabrics

[rmoak at sixmoondesigns.com (Ron Moak)]

>> so what happened to the idea of an ultralight external frame pack?  <<

In short an ultralight external frame is an oxymoron. In the 50 years since
Dick Kelty's first aluminum frame, lots of effort has gone into the attempt
to lighten it. Yet in reality there's not a lot you can do.

A few years ago I took my 5 1/2 pound '77 Tioga and stripped off the bag,
removed the top rail from the frame and some of the cross bracing. The final
frame came in at about a pound.

Adding back a new lightweight pack bag and the harness, the final weight of
the pack came in at 3# 8 oz. If I was to do it again today, I could probably
drop another half pound or more off the pack.

>> A light weight frame holds the pack bag off of your back making for
ventilation.  I
also like that nothing in the pack is able to stick into me since the bag is
off of your back a bit.   <<

I doubt that there are many people on the planet that sweat much more than
me. A fact that anyone who's hiked with me for more than a couple of miles
will attest to. I was really concerned about switching to and internal or
frameless pack. Which is the main reason for the effort at modifying my
Tioga.

While I've not found a cure for sweating, I've also not found internal frame
packs to be a significant problem. With most packs you can occasionally
loosen the shoulder straps to allow the pack to swing away from your back to
improve air flow for awhile.

>> I'm working on a design using Easton Aluminum tubing for the frame,
otherwise an internal frame pack bag design.  I'm working on getting a
reliable way to bend the tubing to custom fit the arch of my back or your
back or Monte's back or . . . and have just bought a better tube bender to
try out. <<

You don't need a fancy tube bender for bending tubing. Simply cut a panel
with the desired arc out of a piece of 3/4" plywood. Route a grove in the
arc edge and add a strap at one end to hold the tube in place. Then gently
bend the tube along the radius of the arc. That's all Tom at
www.polesforyou.comm does when making up replacement tent poles.

The standard Easton tent tubing is fine for stays where all the forces are
unidirectional. However an external frame need horizontal stiffness. If you
welded together 4 tubes as with a normal frame then dropped it on one
corner, the whole thing will collapse. You'd need a lot of additional cross
bracing.

Easton does have poles of larger diameter. I saw some 1/2" poles when I was
there last October. Using 7075 aluminum poles you could achieve a lighter
and stronger pack compared to the 6061 aluminum used in the Kelty frames.
However the cost of the pack frame would be quite expensive.

-Ron