[TheForge] Re: TheForge Digest, Vol 62, Issue 12

[Mike Spencer]

> When I stick weld anything in my shop especially galvanized parts, I
> run my exhaust fan and ceiling mounted fan until the smoke is clear.

A cheap bathroom exhaust fan mounted inside a short piece of 6" stove
pipe is a handy safety tool that I keep around.

I have a squirrel cage exhaust fan connected to a 16" diameter
hood-like affair over my welding table.  It sucks well enough to make
my forge flue draw backwards if there's no door open but it doesn't
violently and instantly yank every bit of fume away from a weld.  It
just creates a general drift in the air unless the fume source is
directly under it.

So in the (unusual) case of cutting, heating or welding something that
makes nasty fume (or that I suspect might), I can plumb the fan/pipe
widget into various pieces of 6" stove pipe that are laying around and
put one end within a few inches of the fume source where it
aggressively sucks all away.  The other end goes wherever it's
convenient to put it: out a window, up into the squirrel cage exhaust
pipe or wherever.

It's reassuring to see, say, zinc oxide fume rising 2 inches off the
workpiece, making a right angle turn in mid-air and disappearing.

Professional welding shops, of course, have exhaust systems "powerful
enough to suck prairie dogs from their holes",  with metal flex octopus
arms for this purpose but that's too many bucks if you only need it
one or twice a year.


- Mike

-- 
Michael Spencer                  Nova Scotia, Canada       .~. 
                                                           /V\ 
mspencer at tallships.ca                                     /( )\
http://home.tallships.ca/mspencer/                        ^^-^^