A quick and easy way to etch aluminum, or really almost anything, with the sand blasting cabinet (or other sandblasting apparatus). Done at Techshop San Francisco.
Step 1: Pick Your Material
Material selection will impact how easily it etches and the overall look of your finished piece. For this instructable I chose a piece of aluminum, Im not sure what grade my piece was, however I can say that a piece of 2024 I tried would not polish up very well.
To get a bigger contrast between the etched and non etched portions find something with either a great smooth surface to start, or one that can be either polished or made very smooth otherwise.
Step 2: Polish the Surface to Get a Good Contrast
I wanted to get maximum contrast on this so I took my aluminum and shined it up with a polishing wheel. This is not absolutely necessary but leaves it looking better at the end and is way easier to do now than after the fact.
I used a polishing wheel on a standing grinder, with a bit of polishing compound. You can get small polishing wheels for a Dremel or even use some fine steel wool and then a polishing cloth or so. Really anything you can do to clean up and shine up the face will be good.
Step 3: Mask Off Your Design.
You can do this with just about anything that will stand up to the sand blasting for a few seconds. Masking tape will not likely work, I used vinyl contact paper as it is nice and thick.
You can also cut your mask in any manner you want, if you want to make a logo and have a sticker, maybe just cut out the letters, etc. For this I used the vinyl cutter at Techshop and actually just cut a sticker using the test function. This machine is awesome as it will turn your vector file into a vinyl sticker.
Probably best to clean the surface with alcohol or some similar to ensure good adhesion as the sand blaster will hit it with some force and if the mask peels up its going to mess up your results.
Step 4: Sand Blast Away
From here I just put my piece into the blast cabinet and go to town. Will only take a few seconds as aluminum has a soft surface, steel will take a bit longer. Glass, plastic, wood and lots of other stuff can be etched like this, just make sure that your mask will last through the process. Doing something really hard like steel or titanium may require a thicker mask to ensure the sand blasting doesn't eat through it and mess everything up.
Step 5: Remove the Mask and Ta-DA!!
Peel the mask off your piece and you are good to go. If you are etching something soft, like aluminum be sure to blow off any left over sand or media so you don't scratch the polished portion.