This Instructable shows you how to recycle a used mailer into a spiffy new no-sew lunch bag.
Step 1: BoM
Used Tyvek/Tyvek-like mailers
Tyvek tape (optional, but helpful)
Strong double sided adhesive (like Zots)
Step 2: Prep
Prep the bag by removing as much of the mailing/shipment information as you can. The bag I'm working with had a 5x7 label on it that was a pain to get off. The most important thing is to remove any identifying info. I also tried to remove as much of the black print as I could.
My bag also looked like it wasn't 100% sealed at the ends, so I added Tyvek tape to secure them. I ended up taping the entire bottom.
Next, I turned the bag inside out, making sure both corners were fully pushed out.
Step 3: Folds
First (pic 1), smooth out the bag and then fold from the bottom up about 2.5-3". Smooth the crease. Turn over and repeat on the other side.
Second (pic 2), fold the edges up to the horizontal crease line, making a triangle. Smooth the crease. Do this on both sides and then turn the bag over and repeat.
Third (pic 3), find the creases on the horizontal lines where all of the creases meet.
Last (pic 4), fold the bag from where all the creases meet towards the center of the bag. Smooth crease and repeat all around the bag.
This is very similar to the newspaper pots demonstrated in an Instructable from last year.
Step 4: Shape
Open the bag and use your hands to shape it. You should find that the triangle ends pop down and the bottom of the bag is flat. The bag I used is very crinkly so it doesn't look as smooth as it should.
Step 5: Adhere
I used Zots dots to adhere the bottom flaps of the bag towards the end. Extra security and helps the bag stay straight.
Step 6: Stamp
If you're so inclined, archival inks are great to use on tear-resistant bags.