Re: Anodizing Engravings

--- In CAD_CAM_EDM_DRO@egroups.com, William Scalione <scalione@h...>
wrote:

> A while back I asked a question about painting engraved letters in
> anodized aluminum. Got a lot of feedback and performed a little

test.

>
> I engraved 2 small aluminum panels, and immediately after engraving
> washed the panels with acetone to remove the cutting fluid. I then
> applied alodine to the engraved area and rinsed with water.
> A few days later I painted the engraved letters with some epoxy
> paint and let it dry. Sanded off the excess on the unengraved part
> and had them anodized. One was painted white, which was black
> anodized, and the other painted black which was clear anodized
>
> The black anodized panel with white lettering did not come out too
> good. The black dye didn't seem to soak into the metal close to the
> white paint, so there was a lot of small aluminum color blotches

near

> the lettering. I'm unsure why this is.
>
> The clear anodized panel with the black lettering came out perfect.
> Looks very professional. This is the way to go if you need to do
> something like this. Just be sure to etch or alodine the metal first
> so the paint has something to grab on to. I guess the epoxy paint
> is impervious to whatever they use to etch the metal before

anodizing.

>
> I will probably build a control panel for EMC using a keyboard

circuit

> board and some switches using the clear anodized finish when I get

time.

>
> Is it possible to hook up 2 keyboards to a computer just by wiring

them

> in parallel, or does anyone have a circuit to do this? I really

don't

> want to
> switch between the two.
>
> Bill

Bill:

I see that the epoxy thing worked (sorta). The reason the black
anodized thing did not work properly is that the epoxy paint is
agressive enough to penetrate the alumunium and act as a resist to
the anodizing. Any color in anodizing has to "stain" the metal. I
suspect that a more agressive pre-sand prior to going down the
cleaning line would help solve the problem. My experience with the
paint you used is that it sticks well to aluminum even with a minimum
of cleaning so it has a level of penetration.

The problem you will probably run into is that a lot of companies
will want their panels some color with contrasting lettering.

As for the keyboards in parallel....the problem may be in the POST
(power on self test) of the computer where it tests to see if a
keyboard is there and gets a reply. Some BIOS's allow you to turn
off keyboard tests. I do know that there are barcode readers that
use a "wedge" in parallel with the keyboard so that when you scan a
code the characters are sent just like you had typed them from the
keyboard. Perhaps there is a signal wire on the keyboard that you
could disconnect to make it "dumb". It's been a LONG time since I
had to work at that level of hardware interface.