I made a serviceable stuff sack from a used tyvek postal envelope. I have been using it for about a month and it is holding up very well. It seems to be waterproof and pretty strong. (I tested it by filling it with water and hanging it in the sink for a while). This may be something that everyone is doing, but I thought I would post in case someone has not.
- Used postal tyvek mailing envelope.
- Paracord or accessory cord.
- Dental floss
- Cord lock is nice but you can make do without one.
- Large needle
- Straight pins
- Cut the open part of the envelope so that is is even. I didn't lose too much of the envelope because I opened it carefully when I received it. If you want a bigger sack, try to retain as much of the material as you can.
- Make small slits about a half an inch long on the side of the envelope. This will be folded over to form the channel for the cord, so the size should vary depending on the type of cord you have on hand.
- Decide which side of the envelope you want for the outside of your sack. I like the plainer side which in this case was the inside. You will want that on the inside as you sew. You will be inverting the sack when you finish.
- Cut a piece of cord to use as your drawstring. You need to have it an inch or so longer on each side so that you have a bit extra cord when the bag is fully open. I left mine a bit longer.Place your cord near the top of the envelope then fold the top of the envelop down over your cord. The slits at the side seams will allow you to do this.
- Snug the cord to the top of the channel and pin the folded edge tightly in place. This will hold the code while you sew.
- Using the dental floss and needle begin stitching the channel closed. As you stich, you can remove your pins. I snug the cord very tightly into the channel, but it makes it a bit stiff. You can have the channel as loose or tight as you like. A snugger fit will add more strength to the overall bag, I think. I go around twice making two independent stitch lines.
- Once you have finished your initial sewing, invert your sack and see if you need a stich above the slits that you made. I usually drop a stich in there to make sure the slit will not tear under stress.
- Add your cord lock and you are done.
It is pretty plain, but I can add a photo is anyone is interested. This works really well. I also used one of these envelopes to make a rain jacket for my small dog.