mask up the machined surface and cut away excess tape -pretty easy as the machined surface is grooved, or just make a tool that attaches to the the edge of the rim and is a certain distance from the edge, which will cut a nice circle
or
ride the bike for a week or two and the paint will magically disappear
btw, tynans method relies on the wheel being built, so unless you are painting spokes there will be a lot of masking tape needed to cover other parts
mask up the machined surface and cut away excess tape -pretty easy as the machined surface is grooved, or just make a tool that attaches to the the edge of the rim and is a certain distance from the edge, which will cut a nice circle
or
ride the bike for a week or two and the paint will magically disappear
btw, tynans method relies on the wheel being built, so unless you are painting spokes there will be a lot of masking tape needed to cover other parts
just some ideas