When packing for a longer trip, especially in the winter, I often find my old Haglofs backpack to small. Instead of buying a new backpack I made a frontbag and a backbag to expand the packingspace.
Step 1: The Frontbag
PU coated Cordura 330 den
YKK aquaguard 5VT profile zipper
20mm nylon webbing
Gear clip carabiner
Side release buckles
Designing the bag I took a rectangular piece of cordura to make the front and back of the bag i one piece. The design of the ends of the bag will form the bag. I formed the ends like assymetrical dropshape.
All sewing of zipper and transverse webbing must be done before sewing the ends. I sew the transverse webbing to fit the longitudinal webbing. But tight enough to stop the female buckle-ends.
Doing this will allow me to release the buckles and let the frontbag hang in the male buckles in the carabiners. When the webbing and the zipper was done I turned the inside out and sew the ends.
Before turning it back I waterproofed the sewings with seamsealer.
Step 2: The Backbag
My design for the backbag is like a standard drybag with folding top.
I made a cylinder with oval bottom. Again it is important to sew the webbing before closing the cylinder.
I chose to make the seam on the back of the bag to minimize the rain impact.
I sew the longitudinal webbing with gaps that fit the transverse webbing.
The transverse webbing has carabiners to connect to the molle system on the original backpack.
All the webbing and the seam at the cylinder sewn, I turned the inside out at attached the oval bottom. All seams treatet with seamsealer to make it waterproof.
Now I'm ready to pack.