Spraypainting Homebuilt Radio Equipment

Building homebrew equipment is no easy feat. The “Look and Feel” and the cabinet housings are the problem. I manufacture mine out of aluminium sheet and then spray paint them myself. It’s not difficult to get a professional finish. Here is the steps you must take.

The problem with aluminium sheet is that when it is rolled in the mill it has an oily substance over a smooth surface finish. Basically, paint will not adhere to the surface. I first use a small orbital 1/3 sheet woodworking sander to roughen up the surface. Use 220 grit “wet and dry” auto sandpaper and use it dry. It will take the gloss off the alloy and render the surface with tiny “swirls’ patterns. Then wipe the surface with mineral turpentine to clean it ready to spray. The swirls will disappear when the paint goes on.

Your local auto supply store will have a great selection of spray paint. I prefer Nissan hammertone charcoal grey touchup spray paint. It matches my Yaesu gear and is about $12.00 a can. Pick up a can of etch primer at the same time.

Place the panels or cabinet to be painted in your kitchen oven and bake for about 20 minutes at 40C and use a clean cloth to remove from the oven. Spray on the etch primer. It will hit the aluminium surface and dry in seconds. Put it back in the oven and turn the oven off to bake the primer on and cool down.

While it’s still warm about 35C and the surface is dry to touch, remove the item and spray lightly but evenly with the colour spray. Do not attempt to cover everything the first coat. Wait till it dries and cools and then spray the second or top coat on. You may want to place it back in the oven at 30C for 20 minutes again, turn the oven off and let it cool down. Remove from the oven and leave the item for a few days until the surface is cured and hardened and then you can step back and admire a perfect homebrew paint job. This is an example of what can be done with a spray can and a little ingenuity and your wife’s oven. Note the “reflection” on the top panel

Homebuilt Antenna Tuner

One of the problems with homebrew gear is the lettering. I use “Dekaset” rub on lettering in white to stand out from the black background. It is also available in black for light coloured front panels. If you spray a cabinet, the front panel will have to be a lighter shade of grey to make the letters stand out. After the letters are placed in position, a single coat of polyurethane varnish put on with a tiny artist’s brush will insure that they don’t rub off with use. The finished product will look professional and will enhance the look of your radio shack

73, Lee ZL2AL

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