[TheForge] DIY Electrostatic paint gun

[Bruce Freeman]

That's my understanding from Jim Bomba, as of the Dover Conference.  I
expect that electrostatic attraction is important in powder coating
because the powder may be less inclined than paint to stick to the
object.  However, the principle works for spraying paint as well.

Bruce
NJ

>>> jchob at verizon.net 10/1/2004 11:58:52 AM >>>
	Correct me if I'm wrong, but isn't this the principal behind
powder
coating. Electro statically depositing a powered pigment onto an object
then
heating until it melts and forms a coating.

-----Original Message-----
From: theforge-bounces at mailman.qth.net 
[mailto:theforge-bounces at mailman.qth.net] On Behalf Of Bruce Freeman
Sent: Friday, October 01, 2004 9:09 AM
To: theforge at mailman.qth.net 
Subject: Re: [TheForge] DIY Electrostatic paint gun

No.

But I've seen how certain scientific apparatus that uses the same
principle works, and there's not much to it, really.

The nozzle must be given one polarity, the object being painted, the
other.  I don't know whether it matters whether the "paint" is
positively or negatively charged relative to the object.

One VERY serious issue is voltage.  High voltage is needed to provide
the desired effect.  High voltage CAN be dangerous.  However, the
current need not be high at all.  Microamps might do (I haven't tried
to
figure it out).  

If I were to try this (which I'm thinking of doing, but don't know
when
I might get to) I would start by using as a voltage source one of
those
room-ionizers commercially available.  They have a needle that points
out into the room, the source of the ions.  (I'm not sure where you'd
find the "ground" on the thing.  It probably is the electrical ground
of
the house electric, but I don't know that for sure.)  The advantage of
these devices is that they are intended for household use.  You can
probably get a little buzz from them, but nothing lethal.

Another alternative would be the flash attachement to an older camera.

These charge a capacitor from a battery.  I don't know that the
voltage
is high enough ( they can give you a surprizing shock), but if it is,
it's certainly a safe source.

I would be inclined to avoid such things as the corona discharge P/S
from a laserjet or xerox, as those things may very well put out lethal
current.

Hope this helps.

Bruce
NJ

>>> sjs at chargin.org 10/1/2004 12:54:58 AM >>>
Has anyone ever made or seen plans on the net on how to setup your own
electrostatic paint system? Ive looked into whats available here and
its
quite expensive, I know little about it but its a high voltage/low
amps
setup which puts a strong electromagnetic field infront of the nozzle
of the
spraygun, the item to be painted is negatively charged and the
positively
charged paint jumps onto it just like powder coating. Seems to me the
"black
box" etc wouldnt be hard to build yourself. Maybe theres more
complexity
than I understand in the system? Anyone got a lead for me, Ive done a
bit of
googling without much success...

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