I have always had trouble with fogging up. I bought the X-Wind fan, but it just didn't have the power to effectivly clear the fog. When I saw this post, I wanted to try to make my own. The problem was I couldn't find any fan that was small enough.
Later, my X-Wind fan was damaged and got another one. It was then that I got an idea: If the X-Wind worked so-so with one fan, what about with two fans?
So I took the fan out of the damaged X-Wind and worked on getting a second fan in the new one. The first thing I saw was that there would be no room inside the X-Wind for batteries with two fans inside. Any battery would have to go outside.
The next thing I noticed is that each fan is set in a piece of molded plastic so that it will only fit on one side of the X-Wind. To have a fan on the right side, I had to make a few modifications. I used a Dremell tool to cut away the little plastic flaps attatched to the fan. Then I took the old plastic piece that used to cover the battery and cut two little flaps out of it. Then I superglued the little flaps to the fan. Now the fan is a mirror image what it used to look like. Now it can be placed in the X-Wind right next to the other fan (after a little more shaping of the body with the Dremel).
I then wired the two fans in series using the existing switch and a 9 volt battery. I taped the battery to the top with some electrical tape. It fits in nicely behind the visor of the mask. Now I have two fans running with the power of 4.5 vots each. They are only 1.5 volt motors so they are really humming! It's pretty damn loud when it's running, but this baby's got power! The motors have not shown any ill affects of running under the increased voltage and I've used it for several months. No more fogging problems at all. All it usually takes is 5-10 seconds to remove the worst fog. It has about the same sound and airflow as a dustbuster, so you can't use it if you're hiding.
It was a little bit of work, but I had fun doing it and I'm happy with the results. Sorry I don't have any pictures.