Marking on anodized aluminum

[Richard Rumancik]

I have been making some sample legends on black anodized aluminum. They look pretty good straight on, but I find that if I look at it at an angle some of the characters look shiny. I want to achieve a consistent "gloss" level on all the characters. Anybody have any suggestions?

[Mike Null]

If you have a gloss you may be using too much power and going right through to the aluminum. Your engraved color should be an off-white and it will be matte rather than gloss.

It's quite easy to over power this kind of a job and it's a little harder to discern with black than other colors.

[Dave Jones]

I agree with Mike. I do black anodized aluminum a lot and the marks are a matte gray/white.

Try doing some tests on a scrap of the material, starting at a low power. I did variations of about 5% power until I got to the right area and then did some tests around that area with 1 or 2 percent changes. Too little power and the mark is not as good. Too much and it starts to "bloom" (text gets thicker)

It will never be a pure white like silkscreening. It's going to be a light gray.

[Mike Null]

Here's a job I just completed yesterday. These are 8" x 10" for outdoor application.

[Joe Pelonio]

You will get differences between maufacturers, in the anodizing. Doing a big job it's always good to get an extra to test on first.

[Mike Null]

Joe

You're absolutely right.

I did one large job where I engraved and re-engraved and re-engraved. Couldn't get a good image. I did this on every piece and sent the job to my customer with a blank invoice and explanation.

He sent them back to the anodizer and got new stuff which worked great.

He filled in my invoice at twice the price.

By the way, I thought my brand new machine was the culprit for awhile.

[Dave Jones]

If doing anodized aluminum for outdoor signs it is a good idea to know who did the anodizing and to be able to talk to them. There are different dyes used in anodizing and some are rated for outdoor use, while others will fade within a couple of years outside.

[Mike Null]

Dave

I imagine that's true but I've been using Johnson Plastics stuff for several years and have excellent results. MO Botanical Gardens also uses it and their signs last several years.

I have only used black for outdoor applications though. No experience with other colors outside.