Originally Posted by Warlan
I disagree regarding the strength of miter corners vs butt ends. Miter joints look nice (which you won't see when it's BOC stretched over the frame). Neither are sturdy or self supporting for squat. That's why you use bracing. Now if they were splines, half miters, lock miters you might have a point but that's not what you were telling him to do. And none of those miters are going to be nearly as strong as a glued 12inch piece of plywood on each corner.
You need to go back to Corner Framing 101.
But first, I don't think you can point to a single instance where anyone, myself most importantly, ever suggested that a Frame under tension that uses Miter Joints did not still need adequate bracing at the Corners and at any actual Butt" joint.
I'm not even sure why you'd imply that.
But as far as a Miter joint's penchant for having better strength, the top and bottom corners of a Miter distribute stress equally and in different directions when such stree is applied. A Butt joint has the bottom inside edge act like a lever to lift the opposite corner up and away if stress is applied. That is why such unions are prone to springing loose with a minimum amount of applied pressure.
Now absolutely, the addition of bracing serves to mitigate such detriment loosening. Obviously, braces on the Butt unions in vertical (Center" supports are necessary. It would be crazy to expect any such Butt Frame to accept any degree of tension, lateral or diagonal, and maintain a true dimension for long. But combining Miter Joints AND Bracing is an exercise in ideally supporting such structures.
Not of course, if someone found it impossible to do Miters because he was afraid of cutting wood using a inexpensive Miter Box guide (improbable) and had a store pre-cut all his sticks, then using "L"s and "T"s could in the least acco0mplish something akin to a satisfactory Frame. I don't dispute that. But the validity and superiority of a Miter Joint has been proven for....say, about a couple Thousand years on now, so arguing that it is not better to use whenever possible is just so......well, it's not to be argued.
In my Tutorial on constructing Black Velvet Wrapped Trim, I show examples of both Miter and Butt joined Trim. Done right...and with precise measuring and assembly, the Black Velvet will effectively hide the straight Horizontal line a Butt joint creates....pretty well. But NOT as nicely as a Mitered joint does...if also done with precision.
But we are not talking about unsupported Trim, are we?