For once, our inexplicably crummy weather worked for me today. It gave me the time I needed to devise a temporary solution to my computer problems. Moreover, you can be sure I'll never delete pictures from the camera again before verifying they were safely transferred to the computer. My procedures are all idiot-proof, but that doesn't necessarily mean they are Otis-proof.
During our technical difficulties, I worked on the newly-discovered knothole that was hidden behind the metal patch. Here it is, seen by human eyes for the first time in well over fifty years.
This knothole is about four inches at its widest, and as you can see, a small crack has opened through it, and a very large one below it. Moreover, the wood above the large horizontal crack has sprung forward. In short, we've got quite a mess here.
If the siding were not so terribly weathered, I could simply replace this piece of siding, because I have at a few hundred board-feet of it up in the garage rafters. But a new piece of siding would stick out like brown shoes with a black teddy, so I decided instead to patch the hole with epoxy putty. Before I did this, however, I needed to insert a backing for the putty in behind the hole. I determined that if I made the backing piece long enough, I would be able to pull the sprung part of the wood into a closer alignment with the rest at the same time.
Consulting my stash of Junk (with a capital J), I found the perfect backing piece, a long, narrow strip of quarter-inch-thick poplar. Poplar was a perfect choice, because it is an even-grained hardwood that I could count on not to split when I drilled it, even near the edge.
Here you can see that I marked its halfway point for reference, and wrapped a piece of string around it so that I could maneuver it into position without dropping it into the wall. This I did in a dry run, determining the best position for the piece so that I could both back up the hole and provide a brace with which to bring the crack back in line. Before removing the piece, I noted where the halfway mark was so that I could put it back in the same position later.
Then, I prepared the siding. First, I marked the position of the patch on the outside of the wood. Then, I marked where to place the screws that would hold the backing in place and provide the clamping action to pull the sprung wood back in. Then, I carefully drilled a hole large enough to clear the threads of the screw, and then drilled a countersink so that the screw head would seat below the level of the wood. I did this to prevent the very real possibility of cracking the siding with the screws. Note that the clamping action of the screws depends upon their threads only engaging the backing piece, and not the siding. This is to ensure that the screw pulls the backing piece tight against the siding.
I didn't rely upon screws alone to hold things in place. I also used some 5-minute epoxy. I could have used a longer-setting epoxy, but 5-minute is what I had. While all of the clamping work is done by the screws, the epoxy will help keep the mend stable, plus it helped to keep the backing piece from falling as I maneuvered it into position. Once I had it in the right place, I held it firmly with the string while I drilled tiny pilot holes in the backing piece and drove the screws in, which I did with a plain old manual screwdriver. This gave me precise control, and allowed me to feel when the backing piece had been pulled tight against the siding.
You will notice that I used screws with a large head; I did this to spread the holding force over a larger area, to help prevent splitting the wood.
In order to complete the backing of the hole and partially fill the void, I then attached another small piece of wood on top of the backing piece, Fittingly, it is a piece of plaster lath scavenged from the inside of the house. This piece I split on purpose, in order to drive the halves out to wedge against the irregular sides of the hole. This will make the hole easier to putty up. Notice that I had to drive a third screw on the other side of the crack; this proved necessary in order to provide enough clamping force to pull the upper part into alignment.
It was then too late in the day to putty, so I went to the garage and cut out a cardboard pattern from one of the aprons with an X-Acto knife. This pattern will provide a guide to aid in the replacement of a missing section of apron on the other window casing.