Faceplates (etching aluminum?)

[Martin Czech]

> 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).

Interesting. How did you do that? If I try to get some photoresist on
something there will always be dust particles, soaking up the thin
photo film in their neighbourhood, i.e. my photoresist gets  ugly
"holes".  Do you have a cleanroom at home ?

>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). 

Alu develops almost instantly a oxide layer, when in air (oxygen).
No water needed. This makes it difficult to get a good electrical connection.
I'm still working on this problem.

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

Guess : keep the photoresist and change the etch solution.
Guess : try H2SO4 (sulphouric acid ?), NHO3 (nitrogen acid ?), mixture out of both.
        A mixture out of both acids will disolve even gold !
        Could work. If you are married, take the ring of, or you're in trouble!

Attention : hazardous gases, wear goggles (protect your eyes), gloves,
ventilation.  Mixing acids with water and other acids can produce much
heat, the solution may overcook !


m.c.


p.s.: I know a company that uses blue photoresist to coat alu panels.
      Looks cool (blue & "white" alu), also not very sensitive to scratches.
      About 12,- DM development cost, 10 DM for each panel.