[simpits-tech] RE: making your own panels

[Marv De Beque]

Well, if you silk screen the panel, why would you etch or mill them?  The
silk screen can simply have the lettering blocked so that no paint is
applied to the letters, but paints the field around them black.  That is
what silk screening is all about.

I have done successful experiments with white spray can paint and have had
excellent transmission of light through the paint.  Any system you adopt
just needs to be consistent.

Again, from my experiments, clear Plexiglas is the way to go.  I think the
frosty look is actually a surface treatment you see.  If you polish the
plastic I would bet it is clear.  Again, knowing what I know about light
pipes, you need an optically clear medium.  Light will reflect off the edges
for two reasons.  The primary reason has to do with the actual boundary
layer.  The n, or refractivity of the material changes at the boundary
layer.  Adding white paint helps reflect what light does not refract back.

For example, the n for a water/glass boundary is easy to see when you drop a
fork or straw into the glass.  The handle looks bent when you look down into
the glass.  That same principle is how a light pipe works.  You need an
optically transparent media.

Marv



On 1/5/04 3:54 PM, "Jim K." <JimK at sisna.com> wrote:

>>>>>> Message: 1
> From: Marv De Beque <mdebeque at woh.rr.com>
> Subject: Re: [simpits-tech] RE: making your own PANELS
> Use clear Plexiglas not translucent or opaque and spray paint the all sides
> (top, bottom, and sides) white with a uniform coat.
> Turn the panel upside down and spray paint the back and sides flat black.
> Silkscreen the top layer flat black with acrylic paint.
> Marv>>>>>>>>>>>>
> 
> Marv,
> That would definitely be a good way to make the panels. You could also mill
> the lettering into the panel.
> 
> If you are going to make panels that you can backlight then you need to
> make sure the white paint you use allows light to pass through.   Applying
> the black top coat of paint via silk screening should produce a nice
> uniform thickness of paint which would allow you to laser etch the
> lettering into the panel.
> 
> I think the big obstacle in making your own backlight panels is determining
> the panel material and the correct paint to use that both allow light to
> easily shine thru.
> 
> A clear piece of plexiglas might not be the best solution for the panel
> since the LED light (or whatever you use for a light source) would not
> diffuse very much and it would be more like a spot of light.   But I would
> have to do some testing to really check that out.   Hopefully something
> easily obtainable like plexiglas would work as opposed to some sort of
> unobtainium.  :-)
> 
> I know the material the real panels use have a sort of hazy, milky
> look.   I actually think the real panels are epoxy filled.
> 
> The real panels I have taken apart have that hazy center section or
> "plate".   The plate is then covered with a white "paint" layer that is
> about 0.010" thick and then the whole thing is painted with a layer of
> black paint again in the 0.010" thick range.
> Jim
> 
> _______________________________________________
> Simpits-tech mailing list
> Simpits-tech at simpits.org
> http://www.simpits.org/mailman/listinfo/simpits-tech
> To unsubscribe, please see the instructions at the bottom of the above page.
> Thanks!