Topband: Keeping tuning boxes dry.

[K9RBorowski]

I've been using grey plastic electrical boxes with gasketed covers from Home Depot for a good number of years now and found that they are pretty impervious to U.V. and temperature extremes. Some are over 10 years old exposed to the Florida sun and still appear like new. I started using 3/32" drilled holes in each bottom corner and found that they were still large enough to let tiny ants and other small insects in, then they die and the decayed remains would clog the small holes. I found a far better way by using a 7/8" to 1 -1/4" hole saw in the bottom of the box and cover it from the inside with a bit larger piece of window screening and use a glue gun, epoxy, what have you, to secure it to the box. I use JB Weld. You can forget about any condensation build-up or small insects after that. One may wish to use a piece of Fiberglas furnace filter material over the screen in a real dusty area but my location hasn't needed that and all has stayed clean inside the boxes. I've had various boxes with cheese slicers, ceramic transmitting caps, vacuum variables, motorized roller inductors, switches, and open relays with no problems whatsoever since using the screening method. The previous 3/32" holes all got a dab of silicon caulk to seal them once I found this method worked so well. 
73, -=Rog-K9RB=- (playing topband for 45 seasons now and still experimenting)