Working with Flexible Trim, continuedCutting floppy crown. I
cut crown in position whenever possible, using a curved jig to
hold the material upside down (see Figure 1).
jig allows the author to cut flexible crown
molding in an upright, upside-down position
-- just as you would solid crown. The
flexible plywood fence is screwed into
place so that it can be relocated for
It takes a little while to make the jig, but once you've
made it, you can reuse it for other radii. I usually make the
fence 4 feet long, but the curved support can be as short as a
foot or so. Orienting the plywood's grain vertically makes
bending it easier.
Once I determine the miter angle with a Bosch Miter Finder, I
place the jig with the cut line, which I call the "diameter
line," at 90 degrees to the fence and close to the blade. On
most saws, you have to set the miter angle first, then position
the jig. After I make the first cut, I hold the molding on the
wall and mark the second cut. A series of nails along the wall
and ceiling can help support this unruly material (Figure 2).
In most situations, I cut inside miters long and snap them into
Figure 2.Finish nails help hold the crown in place
and free a hand for operating a nail gun. Because the author
uses MDF moldings, inside corners are mitered not
Backer blocks. I highly
recommend putting backing behind crown joints. When you push on
the face of flexible crown, it collapses and may not spring
back. So I carry triangular backing blocks, just like the ones
I use on the cutting jig, to support the void at the joints and
serve as a gusset for splices (Figure 3). These blocks don't
necessarily have to be attached to the wall. If there's a
slight difference in the thickness of the two materials, I'll
use shims to raise the thinner piece into place (Figure
Figure 3.Triangular blocks keep the crown from
bowing in, provide nailing at joints, and make transitions to
regular crown molding easier.
Figure 4.MDF is often thicker than flexible
molding, so shims placed behind the flexible molding smooth the
Fastening crown requires greater care than fastening other
types of flexible molding because nails easily damage the
crown's thin edges. Using 18-gauge brads prevents bumps and
damage along the edge, and the thinner wire size also allows
some tweaking for tight joints and miters.
Like curved casing, flexible crown made for a fixed radius
cannot be straightened (Figure 5).
Figure 5.Crown molding can't be bent in place like
baseboard, and there's little room for error when ordering.
Manufacturers require a specific radius or template, and,
although the material fits in a small box when shipped, it
won't fit around a curve with a different radius.
That means finding the transition point between the curve and
a straight run is critical. Using a straightedge, I check to
see where an outside-radius wall falls away from the straight
run, or where an inside radius lifts the straightedge. I join
those transition points with square butt joints backed with the
triangular blocks. It's a little easier with an inside-radius
piece, because the material can be cut slightly long on the jig
and snapped into place. I cut outside-radius pieces as square
as I can with a circular saw, then carefully fit the rigid
molding, relying on a slight back cut, some whittling, and
Ross Welshis a finish carpenter subcontractor in