Dennis Storzek <destorzek@...>
I have a slightly different take on this, but it may be applicable. I got tired of the paint chipping off wheel rims (the outer face of the tire). Most turned (as opposed to Kadee die cast) metal wheels are nickel plated, and nickel is a hard slippery surface that doesn't hold paint well, and is resistant to etching with mild acids like vinegar. So, I decided to abrasive blast the wheels to give the surface some "tooth". Problem is, one can't wipe off the roughened surface, which means the tread and axle point both need to be masked (I don't bother blasting the wheel backs).
To make the mask I drilled a 3/8" hole through the end of an Accurail car weight, not only because I had one at hand, but also because Accurail weights are .078 thick, just the right thickness to mask the whole tread on a Code 110 wheel ( a thinner piece of metal would work for Code 88 wheels). After drilling the hole, I used some fine sandpaper wrapped around a 1/4" dowel to gently expand it a couple thousandths to fit a scale 33" wheel.
I then took a piece of 1/8" brass tubing a couple inches long and flattened all but the last 1/4" of it, then bent the flat portion into a "jug handle" shape so when the flat portion was affixed to the weight, the round end of the tube covered the axle point. Once both parts were made, I grit blasted them to increase the adhesion of the epoxy I used to assemble them. I fit a wheelset in the hole and positioned the bent tube to cover the axle point and fastened them together with a gob of JB Weld. Not elegant, but effective.
To use, I clamp the mask upright in the blasting booth, and hold the wheels in the hole with a gloved had, blasting first one wheel face, then the other. The thickness of the car weight protects the tread and flange, while the tube protects the bearing. The bend in the tube makes room for the stream of abrasive to get to all portions of the wheel face. The same set-up could probably be used as a paint mask, but I'm not interested in cleaning the mask, and just brush paint the wheels.