Corner Joints on the Back of Island Cabinets

Installers share tips and methods for creating a finished corner on the back of an island cabinet. July 24, 2005

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?

Forum Responses
(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.

From contributor T:
I prefer to use a 90 degree hardwood frame at the corners, and then mount the raised panels between the frames. This way I get a true and sturdy corner that will withstand some abuse, and I don't have to make up special panel rails to account for the mitre. I like the symmetry of all the raised panels being the same, and I don't have the seam directly in the corner which can be damaged much too easily or the possibility of them coming apart.

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?

From contributor A:
A couple of things come to mind. Can you not order panels sized to fit the cabinet back without having to split a panel and wrap it around the corner? Some companies offer custom sizing (for an additional charge, of course) while others only offer standard size panels. If dealing with the latter, wider rails and stiles are usually offered so you can cut the end stiles to fit on site.

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.

From contributor B:
I've found that my FF has about 1/8" reveal over the side panel. I make the back wainscot with the same reveal. More and more I'm just applying doors to panels too though, with a shop-made corner trim with edges shaped to match door edge, since many recent jobs have clipped or radius corners it's just faster.

From contributor C:
If I am mitering 1/4" panels, I have had outstanding success by clamping the panel face down on a straight edge. I then use a 45 degree router bit with a ball bearing guide. For glue-up I then use masking tape placed at 1" or so intervals, and miter-fold the joint. I’ve made out well using this method.