Gluing Set Up
use a full 4x 8 sheet of plywood covered with formica for a glue-up
table, though any sheet goods will work such as melamine. Glue up is
messy, especially when I'm doing it, and dried yellow glue pops off
formica easily with a taping knife. My preferred glues are Wilsonart
yellow glue, which is made by Lock Weld, and Titebond Yellow glue with
the red cap. All the titebond II I've tried is too runny and it ruins
all my clothes.
The 4x8 foot width
will handle most door and window casings. The wider assemblies, such
as wide closets and french doors etc., are clamped on the floor directly
in front of their destinations, and immediately nailed to the jambs
with the clamps still on them, for their own protection as much as to
free up floor space. Our jobs are filled with clumsy oafs tromping on
trim, like it's a sporting event or something. Fortunately, they don't
wear their golf spikes.
Under the business
end of the table, where it hardly ever gets knocked over, I keep an
old pot half filled with hot water and bristling with toothbrushes,
on a cheap electric hot plate. This combination cuts glue squeezout
amazingly fast, and an air gun removes the evidence while drying the
casing - again, fast. We have been using this process on both paint
and stain grade work for years without problems for the finishers -
though for stain or clear finish, we repeat the process with very clean
water after the first blowoff.
To be a worthwhile
method for me, any new method of trimming had to be faster than the
way I had been doing it but without sacrificing quality. The
following is an advertisement and if I get any guff about it, I'll fill
the site full of blinking signs. When I first started preassembling
casings, the only clamp up to both was the Hartford Clamp, but they
rusted easily, leaving black stains where wood, clamps and glue met,
were difficult to operate unless the corners were cantilivered off the
work bench or floor, and they tended to slide the mitered pieces out
of alignment. If the man doing installations wasn't paying attention
to the proximity of adjacent walls, he would sometimes nail casings
home only to have to chisel the clamp off later because the release
lever would hit the adjacent wall and not release the clamp. The pins
were not removable or replaceable either. So I now manufacture and sell
my my own clamps, called Clam Clamps, designed specifically for clamping
mitered casings. They don't rust, and you'll never have to
chisel one off a casing. End of advertisement.
Man, you finished
that beer already!
cut a bunch of thin shims from zero to an eighth or so in 3 or 4 inches
and leave them on the glue-up table. Then we butter up all the cut edges,
slots and biscuits, shove the joints together and align the details.
I use a lot of glue and try to avoid sliding the miters against each
other, because this tends to remove too much glue and can result in
a starved joint. The thin shims are used to adjust the face alignment
slightly when a head or leg has a slight twist, or the glue-up table
itself is torqued.
When it is good, we
hold it in position with one hand, slide a clamp into position with
the other and clamp it home. The Wilsonart glue seems to tack up and
cure even faster than Titebond - which is a good thing in this application.
The clamped casing unit is cleaned of glue then leaned up against a
wall in a way that the joints are not stressed.
Using poplar at 7%
moisture content, and working in temperatures above 70 degrees, the
clamps can safely be removed in 3 to 5 minutes, so long as the casings
are not badly manhandled.
When pressed by either
scheduling, lack of space or, more likely, an immediate need of eye
candy for either homeowner or architect, we use the following technique.
We clamp and lean 4 casing units against the wall. Then we remove the
first set of clamps, clamp and lean another, remove the next set of
clamps in order and so on, until we have 8 , 12 or 16 sets done. Then
we install those with the clamps still on them, nailing into the jamb
only. When finished with those four we come back and do the same with
the ones from which we'd removed the clamps earlier - progressing from
the first ones clamped to the last. Then we take the clamps off the
first batch installed, and start all over again.
But both James Chanbers
and I much prefer to just clamp and lean all day long till we have a
huge tunnel of casings leading to a blank wall, and let someone else
nail them up the next day.
On doors where the
rock is proud of the jamb, we cut back the rock such that 3/4"
or so will be left under the outside edge of the casing. This is most
quickly accomplished with a battery powered skill saw fitted with a
cheap, carbide tipped blade of small diameter to keep the foot speed
down. Good eye protection is a must. The carbide tips do not last long
on the drywall screws, and when all are gone the tipless blade will
do just fine. There is actually less possibility of damage done, less
dust and less cleanup (of the area) required with this method than with
the traditional hammer mashing technique. This job is reserved for the
guy who screwed up worst yesterday; that decision rendered, of course,
by you and I, and not subject to discussion.
Quick Grip clamps are
hooked around the jamb at the inside corners and the casing drawn in
to touch the jamb on those with the rock proud. A 3 ½ “
casing can usually be drawn in 5/16ths without cracking the joint (if
done as described in the above paragraph), providing the casing has
been allowed to sit over night in temperatures above 70 degrees. This
will depend to some extent on the casing profile at the inside edge.
We run a tiny bead
of glue along the outside edge of the jambs before shooting the casings
on - small enough that we rarely get any squeezeout at the reveal. This
adds enormous strength and rigidity to the jambs. Though this effect
is tremendously diminished with pre-primed parts, we still do it nonetheless.
The outside edges of
the casings are nailed off by the man installing the baseboard. That
way, the miter joints have had more time to set up, and the base man
already has long nails in his gun. Also, he has become the sole person
responsible for the door to jamb reveal at the bottoms of doors, and
is reminded of that fact before starting.
Baseboard wedged too
tightly between corners and door casing by quality-consious, though
less experienced help is the primary cause of shrinking door reveals
down bottom. This shift of responsibility to him forces an awareness
of this potential problem.
story pole method of measuring, and the registered stop method of marking
lengths is far more complicated to describe than to do. I could have
set up and knocked down everything at least 4 times by now - if you
started at the beginning of this article.
Each component of this
system also stands independent of the rest. For instance, you can forget
the story pole, and measure traditionally as already mentioned. Or you
can leave out the step above and drag casing and saws all over the house
cut them in place and glue them up on the floor. Or you can cut and
fit, tack them to the jamb, and then clamp them, with or without biscuits.
Miter Joint Strength
no matter how you do it, you just can't deal with such a problematic
joint as a mitered casing any better than with clamps, glue and biscuits.
The biscuits add a lot of surface area to the inside corners of the
joint, and that surface area has glue strength in shear, as opposed
has general guidelines for suggested clamping pressure ranges that should
result in optimum strength glue joints. 100-150 psi for softwoods, 125-175psi
for harder woods, and 200 and up for woods like hard maple. A 3 1/2"
by 3/4" flat casing has a surface area along its miter joint of
3.7 square inches. Assuming a clamping pressure of 125psi for poplar,
you're talking a recommended total clamping pressure of 464 pounds for
the joint. But Titebond stresses that a very thin uniform glue line
is the objective, not enormous pressures, so you can probably get by
My mud bucket fitting
technique required the face or backplaning of cocked casings for a "good
fit" - or more precisely, "a good cosmetic fit". There
is simply no way to block plane mitered cuts so they mate precisely
over their entire surface areas every time - unless you make a career
of trimming just one house. And without continuous contact, glue does
not function well - particularly when in tension.
And nails simply do
not put pressure on miter joints. You would need a seven inch long nail
to go through a 3 1/2 inch casing where it would do any good - at the
inside corner where they always open up. So clamping is the only real
solution - but of course we have know that for hundreds of years. But
now there are clamps out there which will do the job FAST.
Now that wasn't so
bad was it? Only one an a half little commercials.
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