Dust explosions

I posted this on the artmetal site in response to a report on a
dust fire in a duust collector with mixed brass and aluminum

Dust collectors are subject to fires ( explosions) because they
combine a finely divided fuel ( almost anything) oxygen (air)
and a potentiol ignitor from static electric sparks. The make up
of the fuel is not the most important thing - its the static
spark discharge. The wide spread use of plastic hose and pipe
instead of metal ducts increase the risk. All systems must be
grounded properly. All metal parts should be grounded together
with a copper conductor connected to a good ground. Plastic pipe
or hose should have a bare copper wire run down the inside of the
duct connected to the ground. The fire risk is smaller in vacuum
cleaning type short period use. The electric potental bleeds off
between use cycles. Continuous use ducts are another story. The
risk is very much greater in areas or periods of very low
humidity as larger potentials build up and bigger sparks occurr.
I think most everyone has pestered a dog with static sparks
produced by scuffing your feet on a carpet in the winter where
humidity is low. Fresh aluminum dust will make a super fuel.
People are killed and grain elevators destroyed every year by
grain dust explosions. The cause isn’t so much a mixture of dusts
but the system design -don’t be mislead. Jesse

well thank you very much jesse brennan! i finally get a chance
to catch up on orchid posts only to find that you’ve given a
warning about the singularly most plentiful material in my
workroom - the one element that spread its bounty onto every
horizontal, vertical & even upsidedown surface. that it presents
a danger to me mocks the very fiber of safety i’ve been teaching
myself in the past four years! it was obvious that the blue,
pink, blue, pink, hisssss, yellow, pop, pop, hisss fire thingy
could be a teeny bit dangerous. especially if held it over the
head in the old statue of liberty play while bending over to
pick up a tiny piece of metal that just executed a suicide dive
off the soldering block onto the floor. that position can, when
practiced in the vicinity of rack of new muslin buffs, bring to
mind the question of 'what is that burning smell? but i learned.
even that all-time biggy about not trying to stop the rolling
ball of molten solder hell-bent for the edge of the table i
learned. everyone in the immediate area can tell you that i
learned the lesson about mixing Unsecured Flying Objects & a
buff wheel. it took awhile, but i accepted the fact that
somewhere, on another plane, there are a lot of half-polished
stones cavorting in a fun place with thousands of unmatched
socks. i learned. and safety & aesthetics? didn’t i learn about
the need to pay attention to fingers as well as stones? and not
going out in public without checking my nail polish to tidy up
the missing spots now attached to my sanding disks? and to clean
up all traces of the blood from those really intimate moments
between my fingers, the grinding wheels & those stones i didn’t
really think needed dopping? didn’t i learn? and now, jesse
SMITHEREENS!!! sedately sad, ive