There, there bean; it's not that bad. We all know you didn't MEAN TO nerd-snipe us. ![Laughing :-DD](https://www.eevblog.com/forum/Smileys/default/smiley_laughing.gif)
110% true on all counts; I learned this the hard way from my own travels down this very road.
![ThumbsUp :-+](https://www.eevblog.com/forum/Smileys/default/icon_smile_thumbsup.gif)
I built several; the two best were a single 5" AC powered muffin fan and two 120mm slimline 12V ones in a Vee with a single piece of filter across the front of both of them. That one was a bit quieter so got used more, until it got knocked off the bench and one of the fans suffered 2 broken blades. The AC fan has been it for several years, and those are the very reasons why. My recommendations are:
1) Design as simple as possible so you actually bother to build the fu**ing thing. The quick & dirty fume extractor you have on hand ALWAYS beats the one you're "gonna make" for the next three years.
![Face Palm :palm:](https://www.eevblog.com/forum/Smileys/default/facepalm.gif)
Know thyself, plan thine design accordingly.
![Wink ;)](https://www.eevblog.com/forum/Smileys/default/wink.gif)
2) Make it small & convenient so you don't mind keeping it at the back of your bench, and so you bother to pull it up to your work.
3) Choose a fan that's as powerful as you can tolerate the noise, or plan on the hassle of slowing it down. When in doubt, see number one above. 4-6" (100-150mm-ish) seems to be the sweet spot for both.
4) AC-powered typically have a higher power/lower noise ratio. Some of them are little hurricanes though.
![Scared :scared:](https://www.eevblog.com/forum/Smileys/default/scared.gif)
AC-powered is by default less hassle from a use & standby/storage perspective. (As long as you can have nice little plugs like we do in the US)
mnem
![Ohms \$\Omega\$](https://www.eevblog.com/forum/Smileys/default/omega.gif)