Sewing machines and making backpacks, etc.

A link at the PCT Ass'n website took me to Ray Jardine's website.  Interested, I bought and sewed the Ray Way backpack in the 3000 cu. in. volume, size Medium.
A look at the finished pack:  Huge, just really huge even before raising the extension collar.  On reviewing the  website description, 3000 is the main bag volume.  An additional 400 Cu. in. comes from the mesh pockets and the extension collar adds 1200 cu. in.  Total: 4600 cubes.

Modifications for the next bag, a size Large 3000 now under construction, include a sleeve sewn into the back for an air mattress support system and 4 loops  sewn on the seams between the back and the sides for a compression system.

Minimal difference between the shoulder strap separation on the Large vs. the medium.  L sh strap is longer, but not by much.  And it needs 6-10" more length to accommodate things that I want to attach, like pockets, an umbrella holder, hand loop, bungees for holding water bottles and a camera pouch--wait, too much stuff.

The sturdy ray way thread can frustrate users of newer home sewing machines.  Using normal threads, needles and fabrics the top thread and the bottom thread will link or "lock" midway between the top and the bottom of the line of sewing. The thickness of the upholstery type thread increases the tension on the bobbin (lower) thread beyond the upper limits of the upper thread tension, causing the stitches to "lock" on the underside of the stitching. This is most noticeable on seams with only two layers of siliconized nylon for which one might use wimpy normal thickness polyester thread. Some sewing machines will permit lowering the bobbin thread tension.   I also advise trying much larger needles with this big caliber thread.  Maybe size 100 or 110.  That seemed to help me with the thread tension issue a bit.  Another annoying issue can be a jagged lower thread in the finished seam, which also seems to abate with a larger needle size.

Regarding home sewing machines: During the 70's while sewing Frostline kits (outdoor clothing, tents, packs and sleeping bags) our modest sewing machine had a difficult time punching through nylon pack cloth and nylon webbing.  Not too much different from today, with most sewing machines suitable for quilting fabrics, which don't have the thicknesses and coatings of outdoor gear fabric.

If the sewing machine hasn't enough power for the needle to punch through the layers of fabric, one can hand turn the wheel at the right side of the machine.  Slow, but it works.  Failing that, one can just buy a machine from sailrite.com.