This page contains notes on specific construction issues I ran into,
including working with crown molding and panel molding.
Cutting crown molding is challenging, and I
designed my theater to minimize beveled crown molding cuts. Nonetheless, there
were a small number of 90 degree angles that I had to cut. DeWalt's website has
notes on cutting crown molding. The common advice to try your cuts on scrap
material is very important. The angles are very hard to get right, even
using a reference table like the one on the DeWalt website. I personally concluded that
trying to get the angles right by using an angle reference table and doing a compound
angled cut was beyond my skill level. So I ripped a 45 degree block of wood to
put against the fence on my saw, and then simply held the molding against the
angled piece of wood and cut the angle I needed. This worked quite well.
One problem I ran into was trying to align the outside corners of the two
pieces of molding at the tops of the columns. I initially tried nailing each
of the pieces of molding separately, but getting the ends to come together
cleanly, at the right angle, and nailing each piece precisely enough so that the
joint was snug seemed just about impossible. Part of my problem is that the
columns aren't 100% square to the walls in the corner or to ceiling (and for
that matter I don't think the walls are 100% square to each other or to the
ceiling), and that compounded the problem of trying to get these pieces of
molding turned and twisted so that the rested against (a) the column, (b) the
ceiling, and (c) each other all at the same time. I ended up gluing the corners
of the molding together on a workbench before I nailed the molding into place.
Once the glue sets, the joint is so strong that you can bend the molding quite a
bit without breaking the glued joint, and that made installing the molding at
the tops of the columns a lot easier.
Another issue I ran into was how to keep the long runs of molding in place
securely and to make them strong enough to hold the wire runs that I was
putting in them. I didn't want to pound a million nails into the molding. I
started out by putting nailing blocks behind the molding. This is a standard
technique where you cut a 45 degree piece of wood to put behind the molding; you
nail that into the wall, and then you nail the molding into the nailing block.
That gives you a better angle for the molding nail and helps keep you from
splitting the molding. That worked OK, but it still wasn't as secure as I
wanted. Since the molding was nailed well enough to stay up for awhile, I ended
up just placing additional 45 degree blocks of wood between the molding and the
wall with a little bit of glue on them. Once the glue dried, those blocks
provided most of the support for the molding. If I'd discovered this technique
earlier, I would have put even fewer nails into the molding--just enough to keep
it up while the glued-blocks dried.