A friend asked me to make a replacement for an exterior window sill that rotted. The sill was Fir and about 2 1/4" thick and 7" wide with the front edge and ends round.
I had a piece of aromatic Cedar (Juniperus Virginiana) big enough to do the job if I re-saw it and glue it together. So I did and glued it with Titebond III.
Now that I have done it I am wondering if the glue will hold on cedar? And Is there anything special about painting? Just good primer?
I've certainly glued it successfully over the years for things like chest and drawer bottoms but never for exterior use. There are chemicals in this wood that seem to do oddish things to finishes, or so I'm told. Since I've been using it for its chemical-emitting abilities I've never applied finish to it.
Cabots made a primer specifically for cedar called "Problem Solver"
It blocks the oil that seeps from knots and sap pockets. I used gallons of the stuff when we first moved in. The entire house is cedar and in 30+ years, I have no black streaks or knots.
I wouldn't expect a regular PVA glue joint to hold exceptionally well being exposed to elements, I'd be worried about seasonal changes in humidity and heat. I would be less worried if the glue was some construction exterior adhesive type and a joint was doweled, t&g-ed or similar.
My friend came and got it and was pleased. He agreed to prime it thoroughly.
This had a bull nose on it and I had no cutter even close to the right size. So, it started as a piece 7" wide and 2 3/8" thick. I took the old one as a pattern and laid it on the table saw with the blade tilted to 45 degrees. Moved the fence until the pattern touched the blade. Sawed the new piece form both sides. Reduce the tilt of the blade and fit the pattern and repeated sawing the blank. Rinse and repeat about five times, ending up with a faceted edge. Knocked every ridge off with and block plane and then sanded with a ROS. Took less time to do it that to type the explanation. Put the bull nose on the ends with the disk sander and eyeballed it.
My friend commented he does not expect to be in the house more than two years and was certain it would last that long. I admitted I was concerned about the paint sticking to the cedar and his answer was he would just paint it again before putting the house on the market.
