17 Dec
2001
17 Dec
'01
11:01 p.m.
Matthew Sell <msell(a)ontimesupport.com> wrote:
Vacuum cleaning is much more "dangerous" for
a PCB than washing it.
Pete made a very good point, one I had forgotten, the static charge created
by dust moving through an insulated (plastic) pipe can generate some
obscene voltages.
This is not a problem with a little bit of planning.
One of my other hobbies is woodworking. Breathing in the
sawdust from many hardwoods is very unhealthy, so most
well financed wood shops have some kind of dust collection
systems. With flow rates of 200-1100 cfm and long runs of
plastic hose, a dust collector plus sawdust can be an
explosive situation. Thats why grounding kit are sold
separatly or included with most dust collectors. These
kits consist of a lenth of wire that runs down the hose
and metal clamps to clamp the wire to the hose at regular
intervals. These kits are available in most woodworking
stores.
Of course my favorite way to protect a circuit board from
static is to cover the solder side with aluminum foil,
lay it on conductive foam or a conductive plastic bag.
On a different subject:
I've also used aluminum foil to create a ground plane
to cut down on noise on some extender boards. I take two
pieces of cardboard the size of the PCB and wrap one with
aluminum foil. After making sure that none of the solder
joints will poke through the bare piece of cardboard, I
make a sandwich of the solder side of the PCB, the bare
piece of cardboard, and then the aluminum wrapped
cardboard. With this taped to the PCB, I solder a wire
from the aluminum foil to ground on the PCB.
Regards,
--Doug
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Doug Coward
@ home in Poulsbo, WA
Analog Computer Online Museum and History Center
http://www.best.com/~dcoward/analog
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