I like the look of old-time equipment nameplates, the most famous of which probably belongs to the Victrola. This photo shows a real one; this Instructable will show you how to make your own. Great for decorating your creations, especially if they're in a steampunk vein.
Best of all, I made it at TechShop.
Step 1: Equipment and Materials
1. A laser engraver.. The equipment at TechShop San Jose is a epilog 60 W laser engraver, but others will work too with power/speed adjustments.
2. Metal sheet (which can be found at most hardware stores, or at several on-line sources, or pre-cut metal plates which can be obtained from a trophy shop). Brass, copper, or aluminum would all work.
3. Paint. I used black spray enamel for my plates, either glossy or flat, depending upon the look you want. Dark brown would work too.
4. Graphics software. Either to manipulate an existing image or to create your own.
Step 2: Getting Started
The basic concept here is that we will paint a metal plate with dark paint, and then etch away the paint with the laser, leaving bare metal. Therefore, it is important to understand that what is dark on your graphics will end up being bare metal, and what is white on your graphics ends up remaining dark paint. So, it's almost like the graphics file is the negative of the resulting etched plate.
Graphics file: Your design will be created through rastering the laser--no vectors!. Also, while more advanced laser techniques can create "shades of gray", in this Instructable, we will be using black and white graphics only, so when you create or manipulate your image, keep this in mind, and try to enhance contrast if possible while still retaining a good image.
Spray-painting the metal. I used brass in my Victrola examples. I made sure the surface was clean and grease-free by cleaning with acetone. Careful spraying of paint--several light coats--resulted in a blemish-free paint job. I've used both glossy and flat black enamel and both work well. It all depends on the look you're going for. A steampunk plate might be flat, while a plate made for a display might look better glossy.
Step 3: Laser Etching
At this point, I'm going to assume you have access to a laser cutter and are properly trained on how to use it. At TechShop San Jose, the laser cutters are Epilog 60W, and the settings I used were 60 speed and 20 power. Your settings may vary based on the model laser cutter you use. Fortunately, any mistakes you make can be erased easily with paint remover, and the metal plate repainted.
After the lasering is completed, you can choose to either leave the metal bare, in which case, it'll eventually acquire a patina (if it's brass or copper), or coat it with a thin coat of polyurethane or other clear coat (spray can works well).
To give a bit more of what can be done with this technique, this is a photo of a plaque I made for a Plasma Pistol display box, using just some fancy Victorian fonts and dingbats, and etching it onto a painted copper plate.