Home Theater #35 - Finishing the Crown Molding

I really hate seeing seams in crown molding - after spending the time and money to install it, I want to look almost flawless. Here are the details on my effort...

First, I cut the ends of the molding at 45 degrees (same as a miter cut) to join them. This helps align the two pieces, since one lays on top of the other, and provides a large glue surface. I glues the end together and nail through one piece into the other.


Once the molding is in place, I rub wood filler into and small gaps. If the walls or ceiling are not straight, the molding won't typically fit exactly right, and the gaps can get larger. I had a couple cases of this in the theater, so I needed to do some sanding to smooth things out.

To sand the moldings, I created the profile block shown here:

Side view

Here is how I did it:

- I took a shorter piece of molding, set it face up on a piece of news paper, and laid plastic wrap on it.

- Mixed up some Fix-It-All (same consistency as sheetrock mud) and put a on 3/4" layer, letting it run a bit over the sides. This stuff dries fast, doesn't shrink, and is pretty hard. Click on the image at the right for more info.

- I took a small piece of scrap plywood and pressed it down onto the Fix-It-All. This forced it solidly into the profile of the molding, and formed the support for the sanding block.

- I let the block harden for about an hour

- I broke the excess off and trimmed the block square on my table saw.

- I wrapped 100 grit sandpaper around this to sand the molding.

I may try to make a couple more of these with cement mortar, which would be really hard. I have read that some people use Bondo as well.

Here is a picture of a joint in the crown molding, after I sanded it. The best way to do this was to tip the block slightly up and sand the upper profile, then tip it down and do the lower one. I used the square edge of the block to sand the flats.


This photo shows the same molding with one coat of paint on it - the seam has virtually disappeared. I applied this coat as a "primer". Once the final coat goes on, it should be virtually impossible to see the seam. I sanded about 75 feet of crown, with a number of seams, and they all worked well.


I made a couple of blocks in case the first one broke (one is none), but it worked fine with no signs of wear. I am going to coat the surfaces with poly to help harden them further.

Home Theater #34 - Crown Molding

I installed the crown molding in our home theater this morning, and all went pretty well. The following pictures show the fixturing (also called jigs) I build to make it quite a bit easier...

Here is the cutting fixture I made for my chop saw:


The key feature of this fixture, is that it holds the crown molding in the same orientation as when it's installed. In this case, the "trough" that holds the molding is 2" wide and 2.5" tall. This is screwed to the metal fence on the saw.


Why I really like this method:
- It's very easy to visualize the cut. This is great for DIY people like me who don't cut crown regularly - no compound set-ups.
- The cut marks in the fixture allow me the line up my cuts very accurately.
- The fixture holds the molding securely - no sliding around on long pieces.


The next set of photos show the fixture for building inside corners. I have tried to cope inside miters with very limited success. I find it difficult to get a clean profile. I prefer to pre-build my corners, then install them (it takes two people to hold them)...


Again this fixture holds the crown pieces in the same orientation as when they are on the wall.


I glue the pieces, slide them together, and air-nail them from the back-side. Once the glue dries, it makes a perfect miter joint - accurate and strong.


Here is a picture of the corner joint once installed (no additional caulking or painting after the assembly). There is enough flex in the glued pieces to allow me to fit it snugly into corners that are a bit off of 90 degrees. I caulk any gaps.


This photo shows the outside corner, done with a small piece and cut at 22.5 angles. It's not painted because I cut these right before install.


Finally, I put a nailer strip (3/4 x 3/4 pine) in place before the crown. I glue and tack-nail these in place, so I don't have to worry about where the studs are located.


I filled the nail holes and joints between the pieces (cut at 45 deg) to finish of my work for the day. After everything dries overnight I will sand and paint it all.

Building the fixtures took about an hour - and I am sure I made up the time jsut doing the theater room. I am using this crown profile throughout the house, so it was well worth the effort.

Inspirational Design Site

Finding a good site for inspiring designs and ideas is like uncovering a little bit of gold. Ross Chapin Architects is filled full of great house plans and images. The style is very "Northwest Cottage", which what we are basing our remodeling and decorating on.

Here are a few images from the site...





I really like the plans section, which provides floor plans as well as images.