This is my most recent build using a cheap radiator fan and a stand made with maker pipe to create a dog fan to stand in front of my dog boxes when we are working/training The back is a mesh pizza tray. Good fans that move a lot of air are expensive and the batteries have very low amp hours.

Just used the maker pipe connectors and scraps of pipe.

My old O2 cool fans are dying and I had this from another application. (but small radiator fans are cheap)

Add a simple PWM to control speed and a cheap 12 volt deep cycle battery, a digital multimeter, and I have something cheaper and better than the portable Ryobi fan. With a 2.8 amp draw at full speed I can get a good bit of time on a deep cycle battery .