To make the enclosure smooth enough for a quality etch, go over the surface where the graphic will be with 320 and 600 grit sandpaper before applying the mask. This will remove any divots left from the aluminum casting process, which would retain paint and complicate things in the future.

Smooth surface, with only light reflecting any grooves

Once you’re done sanding, it’s time to mask. A light coat of spray paint applied to the sides of the enclosure will protect them from the etchant. Make sure to get the corners and create a solid matte of paint.

A light-but-solid coat on the sides

This next step isn’t always necessary, but since the pedal I’m using for this tutorial was already drilled, I need to mask the inside of the enclosure as well. If the acid was allowed through the holes to eat away at the inside aluminum, there could be a mess of hazards for the delicate electronics this enclosure will house. Things like flaky metal (if not thoroughly sanded- and who wants an extra step?), acidic residue (if not properly washed), and loads of other problems are just best avoided by preventative measures.

A generous coat on the inside

Now once again sand the top of the box- where the graphic will be- with 600 grit paper. Any remaining imperfections in the surface will become apparent, so make sure to get rid of them once and for all. For the icing on the cake, polish the top to a nice high-gloss sheen with the #00 Steel Wool, this time under running water.

Wet-sand under running water to keep the 'mud' from staining the enclosure

The final polished surface, ready for graphic transfer

That’s it for step one! If it seems like a lot of work, that’s because it has to be. As I’ve stated before, preparation of the enclosure is the pivotal step in etching. If you skimp on this step at all, it will show in the final result, even if it isn’t apparent at this point. Just take your time and relax- maybe put on some good music or a long movie if you’re impatient.

But don’t worry, things start moving faster from here on out.

Coming next: Graphic transfer & Touch-up

« Part 2