Mark Clement: Hi! I'm Mark Clement, Licensed Contractor and Tool Expert, here today to show you how to cope various moldings using the Dremel tool. What I'm going to talk about right now is coping basics.
Now, as a frame of reference, it's actually easier to explain coping by showing you first what it isn't and where it's not used. Where you don't use it is an outside corner, which is this. An outside corner is always mitered. Two faces of the molding cut usually at a 45, fit together like that. No problem, pretty basic! However, on inside corners, which this is, people often apply the same principle and they miter the inside corners.
The two faces of the molding fit together like that. However, that works nicely here in the shop. But, in the reality of a house where the floor could be lumpy, there could be imperfections in the dry wall behind. This corner actually is very difficult to get tight on a project, especially when you nail. The nails force the molding to the wall, obviously, but in so doing, often open this joint up, either in the top or in the bottom or both.
So, it's tricky to get right in real-life applications. That's where coping comes in. Now, coping can only be done on an inside corner. The good news is, most corners are inside corners. The secret of coping and why it's so good is this: a coped joint removes one of the faces that a miter joint has, leaving you with a sharp, leading edge that enables you to make both pieces of molding fit in the real world where stuff isn't square and perfect.
The secret here is that piece A actually lays over piece B, like this. So, when temperature fluctuations make the molding want to move around, you can cut this joint so that it stays very, very tight. Once you get the hang of it, it's actually easier and faster to install.
So, those are some coping basics. Up next, I'm going to show you how to cope baseboard molding.