I have quite a few shelves to make which are 3/4 plywood with a 1 1/2 tall by 3/4 thick nosing applied to the front edge. I'm looking for a way to do this with pre-finished plywood. Naturally, the sticking point is how to treat the seam where the nosing meets the plywood. As the plywood is finished, there'll be no sanding after the nosing is applied. I've seen this done where there is a slight 'v' at the joint. I'd guess that if I chose this route, I'd need to edgeband the front edge of the plywood first. Any other methods?
I put a paint-break (1/16" round over) on both the solid wood edge and the pre-finished ply. This way the variation of the plywood thickness doesn't stand out so much and it is easier to finish. I'm sure there are other ways, but this has been the norm in most of the high-end shops I work in.
The trick is to set the router bit to cut into 100% nosing material (i.e., never actually touch the plywood). The very top of the V-groove should come imperceptibly close to the plywood veneer. This way, the entirety of the V-groove is hardwood (plywood just looks goofy in stain-grade work when grooved on a 50/50 cut).
I'd use green tape and newspaper to cover the pre-finished part, stain, seal, and clearcoat the nosing, and done! All this taping may end up more hassle than it's worth and unfinished ply may start looking attractive, unless you just have a ton of prefin laying around.
Comment from contributor A:
You can put a small groove on the back of the hardwood cap, cut it to lenght, finish it, and then use a biscuit joiner to attach to the ply. Use blue tape on all your finished surfaces that the joiner will touch or scratching could occur. The biscuit joiner, if itís a quality one, will give you consistent height between hardwood and ply and give you a blind dado effect. Using paper covered blocks when clamping up your work takes care of marring the finish. We use this method for pre-finished, melamine, and foil jobs. It works great.