have not imaged thick anodized aluminum, but I’m sure
we can. We've experimented with 'laserable' colored aluminum,
but the results did not meet our goals. During anodizing,
an electric current passes through an acid causing the surface
of the aluminum to oxidize. The oxidized aluminum forms a
strong coating as it replaces the original aluminum on the
surface. The result is an extremely hard substance called
anodized aluminum. It can be nearly as hard as diamond under
the right anodizing process (hard anodizing). It’s
very tough and used in many industries including aerospace.
concern was the corrosion of non-anodized aluminum in a salt
environment. Many of us have seen aluminum lawn chairs
virtually disintegrate after a few years outside at the beach.
When we remove the anodized layer to produce the image, that
would expose the raw aluminum. The atmospheric assault on
the photo would not be good. The piece could be coated to
protect it from the environment, but that presents its own
maintenance issues unless we used a synthetic
diamond. That's never been tested with aluminum.
were also concerned about Galvanic
Corrosion. One gets Galvanic Corrosion
by having dissimilar metals in contact in the presence of
an electrolyte. This might be an issue if we put an aluminum
plaque on a bronze foot marker. Anodizing is a standard means
of eliminating the problem. Once aluminum is electrically
isolated the problem is gone. So that worry was no longer
an issue if the
aluminum was anodized on the reverse side,
the side contacting the incompatible metal.
reason we decided not to
pursue the anodized aluminum for our tributes were the dyes used
in the anodizing process. They are organic based, and we
were told by anodizing experts that over time they had a
tendency to fade.
That happens with all organic
based materials. That was deal breaker right there. We were
after extreme longevity, even outdoors.
aluminum itself just doesn’t have the marketing appeal
of surgical stainless, titanium, or bronze. Unfortunately,
aluminum is many times associated with lawn chairs and pots & pans.
I personally have never seen an aluminum tribute on a memorial
technique some companies use is a Photo
Etching compatible metal, usually aluminum,
embedded with a silver halide material. When exposed through
a negative film to an exposure lamp the silver halides in
the material turn black and create an image. The unexposed
halides are then washed away. This is not true
engraving where metal is removed from the surface. At left
is a cropped scan of a "Photo Etched" aluminum
plate. The resolution can be very good using this technique. Click on
the image for an enlargement. Sign makers and distributors
say it can be used outdoors, but I would question the longevity
since an emulsion is used in the process. If the aluminum
has a color, its been anodized. I mentioned the fading potential
who designs with and distributes Matthews Bronze, had this
to say about Matthew's Metalphoto™ Portraits on their
Web site. "Metalphoto uses a photosensitive aluminum
sheet, available in either satin aluminum or gold-tone aluminum.
The sheet is exposed using a film negative made from a photograph
using a UV light source. The image is produced in a permanent
black image on the plate. ...Metalphoto is recommended when
the only art available is extremely detailed or the image
itself does not have a lot of contrast (old photos, for example)."
technique does not work
on stainless. We, Immortal Memories™, can handle
old photos and extremely detailed images on stainless,
titanium, and bronze. If you would like to review
a lot of good information, photographs, and products by
Matthews, Gemini, and Trigard we invite you visit the Plaques&Letters Web