Adrian wrote on 04/12/2008 :

At the moment, I've got a couple of mains-operated ec-computer fans mounted
through the timber walls, sucking fumes out from the studio.
Trouble is, they're about 12" away from where the actual soldering is done,
there's not as much 'suck' (!) as I'd like... and they're pretty noisy when
running.

If they are only 12" away, then I would expect them to be fairly
effective at drawing the fumes out. Probably the problem is the
distance they are from the source of the fumes and the fact that hot
fumes tend to rise vertically.

Might you not be better with some sort of funnel to collect the fumes,
directly over where you are working? The idea should be to the fumes
away at their source, rather drawing out air after the fumes have mixed
with lots of it.

Those 12v PC fans are not really that effective, much better would be
the 6" or 8" 240v operated fans intended for main frame computers. You
can get these from electronic surplus dealers for a pound or two and
they will keep going for many years. Google for Bull electronic
surplus, as one possible source.

--
Regards,
Harry (M1BYT) (L)
http://www.ukradioamateur.co.uk