Conard's Photo Etching Blog

Aluminum is a light and versatile metal. However, it has a couple of characteristics that give etching houses fits. It is highly reactive and will etch in both acids and bases. Common photoresist film is designed to repel acid, but to remove it you need to use a fairly high Ph caustic solution. And, oh darn, that etches aluminum, too. So, say bye-bye to dimensional tolerances. For many etchers, the headache isn't worth it. (And, shhh, don't tell anybody... but sometimes they come to us for aluminum.)

Modern aircraft are making use of very high-tech materials, including carbon fiber and advanced composites, for many elements of airframes. But not all elements can be replaced with non-metallic materials.  When it has to be metal, aluminum is most often the metal of choice.