I install high end pre-finished factory built cabinets, and we do a lot of wainscot (or raised panel) type panels on the backs of islands and bars etc. I have always just run the ends trough my 30" table saw on sight to put a 45 or 22.5 degree miter on them and then usually glue and surface pin them together either with 18 or 23 gauge pins sparingly and then touch up.
I do occasionally put a 1x1 nailer behind, and back nail through it so as not to surface nail, but surface nailing is the only way I know to do this and get the two edges to be dead on. I've actually gotten pretty good at this, but sometimes it can be a real problem if things are warped.
Does anyone have any suggestions on how to handle this?
(Cabinet and Millwork Installation Forum)
From contributor P:
On extremely high-end homes I've folded the miter. It is very tricky to pull off correctly in the field however.
I'm not sure I'm following so far. You understand I'm talking about working with pre-finished factory built panels. Also, I am wondering what you mean by "folding"? 90 degree hardwood frames?
We haven't used true wainscoat panels on the backs of cabinets in years. We use typical pre-finished cabinet back paneling with equally sized raised panel cabinet doors attached. Another door is attached to the end panel. A piece of outside corner is used to cover the raw edge of the paneling, and this is going in $400,000 to $600,000 homes. The homeowners seem to like the cabinet doors on the back that tie in with the doors on front.
To fold a corner together, miter the two opposing pieces on a 45 or 22.5 just as you have been doing. Next, place the pieces on a work surface face up with mitered edges together. Place 2" masking tape down the joint, holding both pieces together. Carefully turn the pieces over, glue both mitered surfaces then fold together. The tape acts as a hinge. Use additional tape to hold in place until glue dries. No fuss or mess - unless your wood is warped.