I wanted to make a small fan for soldering, so I dug through my spare parts and found two small fans from an old computer, they are both 12V.
Step 1: Test, Clean, and Gather Material
Test your fan with 12V DC power, clean them, and cut up an old credit card to start.
Step 2: Plastic Weild the Card to Fit Into Corners
Use soldering to bend credit card and use screw to for the bend. Use plastic melts to patch in credit card to sides.
Step 3: Connect
Use longer wire to tie loop around both batteries, join as one.
Step 4: Solder In
Solder in your motor connections, use black tape to tape up the whole thing, and you are done.