Faceplates (etching aluminum?)

[Isac Georg Jensen]

Hello all,

I know faceplates have been disussed before, but I have not been able to
find any solution to my problem in the discussions, so I thoght I would
give it a try on the list:

I was going thru the archives looking for some clues as how to make
good, solid
and most of all homemade faceplates (minimum expenses, opposed to the
fine, but pricey K.Lightner method).

Ron Scott wrote:
> 
> I received a letter a few weeks ago saying that 3M Dynamark has been

..snip..

> I also tried caustic etching aluminum and screen printing this weekend.
....
> 
> Dishpan hands and burnt nose hairs
> Ron

How did you manage to etch aluminum ?

I've tried myself (not being very good at chemistry). I used the
following method
with no luck:

1. I prepare my artwork on a computer and print a negative on
transparant paper (the result is transparant letters and a black
background).

2. After cleaning the aluminum faceplate, and applying a photo sensitive
layer (the same material used for making pcb's), I let the layer dry for
at least 30. min i an oven at 50 degress Celsius (or room temperature
overnight).

3. I then place the (negative) artwork on the photo sensitive faceplate
and apply a light source (Ultraviolet) for about 10-15 minutes. The
photo layer will now react with the light in the areas that are
transparent.

4. After applying the light source, the faceplate is placed in a tray
containg a solution of  1 liter of water and 9 g. NaOH. It stays in for
about 1 minute and gets a good rinse in cold water.

This is exactly the same method I use for making PCB's. The PCB's is
finally placed in FeCL to etch. This does NOT work with the aluminum
(Later I've learnt that Aluminum in FeCl makes posionous fumes). I've
been explained that the reason that the aluminum will not react with the
FeCl, is that when rinsing the Faceplate in water, it develops a
protective layer (Oxidation). 

Hmmm.. ? Next I've learnt that a much less hazardous way to etch
aluminum would be to use NaOH (is this caustic etching ?), but this
would not work on my faceplates, as the rest of the photo layer will
react with the NaOH, leaving a blank faceplate with no protective layer.

My question(s) is:

Does anyone know of an alternative photo sensitive product that will
allow the aluminum to etch in NaOH ?

Can I use another material/solution to etch the faceplates, prepared as
the above explanation ?

 
----------------------------------------------------
Isac Georg Jensen
Department of Information Technology
Building 344, 120                 
Technical University of Denmark	 
DK - 2800 Lyngby                 
E-mail: c908369 at student.dtu.dk, Phone: +45 4525 3678 
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