You know what DOES clean off the residue? Acetone followed by 90% Isopropyl Alcohol. Unfortunately, because I used a paper tissue to apply it, I marred the surface of the acrylic with tiny micro-scratches. Additionally, Acetone is so volatile that it left some of the residue behind (partially dissolved sooty hydrocarbons?). The Isopropyl cleaned off the residue pretty well, but the surface was too scratched to be usable. It also tended to make laser etching imperfections more obvious.

At 30%, the etching was still present, but very light. The upside is that it cleaned off beautifully with Simple Green, Scotch Brite and effort. The downside is that you can hardly see it. At 40%, the etching was deeper, and as an experiment I tried TSP instead of Simple Green, and Scotch Brite. The TSP had NO effect. I even ended up putting some powder directly on the etched surface and made a paste of it with water. Even with effort, it had no effect.

Well, the concept certainly worked, but the acrylic ended up with a coat of blackish soot on it which took a combination of Simple Green, a Scotch Brite pad, and some scrubbing to mostly clean up. There were some bits of cruft between the original acrylic and aluminum that got baked into the etching. The aluminum card got some of its surface etched off as well.

The idea is that by putting the thin black aluminum card below the acrylic, the laser will create a hot-spot on the surface of the black aluminum which will vaporize and/or melt the acrylic that is pressed against it. Since acrylic melts at about 160°C, and boils at about 200°C, the laser's intensity will have to be set just right. The aluminum itself won't melt until 660.3°C and won't boil until 2,470°C, the aluminum will not interact with the acrylic. However, the anodizing itself may come into play, because it has some kind of coloring agent added to make it black, because aluminum oxide (the result of anodizing) is normally colorless.

After downloading and installing Sneakerhead BTN Regular" on my Linux computer, I used Inkscape create an .svg file of Gil's name. I then chose an anodized aluminum business card blank to act as the target for the laser, because acrylic is transparent to blue laser light.

This is the splash-screen for the GEODUCK software. The font is called "Sneakerhead BTN Regular", and it's intended to be etched into a piece of transparent acrylic. The original cartoon of Gil was designed and drawn by Bryan Ross. Gil had an amazing psychological effect on the three different Boeing organizations that contributed to the software design. Gil fused BCA, BR&T and Boeing IT together in an almost magical way. Rivalries and past dysfunctions were erased by Gil's humorous smile.