I recently went on a backpacking trip and I needed a water bottle. I wanted a nice insulated, 32 oz., water bottle that I could get for a decent price. I picked up a conversation where a man said that most of the extreme backpackers don't buy insulated water bottles they usually just cover them in duct tape. So I decided to give it a shot.
Step 1: Materials
Your materials will depend on what you are trying to do. I was trying to keep water cold, so I used reflective tape to reflect heat and non-black duct tape so it wouldn't absorb heat. If you wanted to keep your drink hot then you could use black duct tape.
These are what I used/would use:
light duct tape (not black, white is ideal)
Reflective duct tape (optional)
Black or dark duct tape
Step 2: Adding Foil to Insulate
Now just take strips of foil and duct tape them to the water bottle as shown in the picture. I used three strips that were about 1 inch thick each. They were placed about 1 1/2 inches to 2 inches apart. Then I duct taped over it.
Step 3: Using Duct Tape to Add More Insulation
Now you want to add a couple layers of duct tape around the whole cup. Probably around three or four layers will work. Then, on the bottom, do another 3 or 4 layers but only on the bottom 1 1/2 row. (Refer to pictures) and then do the same to only the top row. This adds an indention for more comfort for your hand to hold the bottle.
Step 4: Putting on the Reflective Tape for Maximum Insulation
Now you just need to add the reflective tape on. Add it to the top row and the bottom 1 1/2 rows only (just like the last step). I don't recommend layering this duct tape but I guess you can. The regular duct tape adds a better grip than the reflective duct tape so I recommend leaving the spot where the indention for your hand is.
Now you are done. I hope you enjoy your new insulated water bottle and have fun with it