Best of all, I made it at TechShop.
Step 1: Equipment and Materials
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
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
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.