Re: capillary effect

[Brian Whatcott <betwys@SBCGLOBAL.NET>]

At 10:34 PM 5/31/2003 -0700, you wrote:
> "This is the process now used commercially to paint for instance,
> car bodies.   The method is labeled "electrophoretic".
> The advantages include lower paint splatter/loss than regular
> spray ..."
>
> Also better at getting into "nooks and crannies"?
>
> Reminds me of the nozzle some engineers were developing in the Hochschule
> für Verkerswesen (Dresden) to paint carriage parts.  The difference was
> the paint was a dry powder and developed its charge similarly to a
> triboelectric Van de Graaff.  Then heat was used to fuse the paint.  (If I
> remember correctly -- that was 1989)
>
> bc


This is a relatively recent commercial introduction called variously
powder coating or e-coating.    The "paint" is provided by polyester
particles. In small operations,  preheated clean articles are simply dipped
into the adherent powder: in mass production, pre cleaned products are
passed through electrostatic powder spray stations, and baked.
The continuous plastic film is specially liked for salt spray resistance.
One supplier mentions a 250 hr salt test for an 80 micron film.

Capillary transport of atmospheric pollutants through the film is
 minimized.
People who finish boat trailers are as enthusiastic as you would expect.

Brian Whatcott   Altus OK