Friday, May 13, 2011

Another Day, Another Something Or Other

I've done two passes with the epoxy putty. I've been using the new putty, and have concluded that the putty I was using isn't all that stale. Most of the difficulty I was having was simply the result of working at the top of an extension ladder; I can't really get a good angle on my work up there. Beyond that, I guess I just have yet to get my puttying chops back up.

In any event, the work is going much more smoothly now; I'm doing just fine with filling holes, but the sculpting part is still giving me a bit of a problem: the putty doesn't always want to come off the knife.

The casing is actually ready for the first coat of primer everywhere but in the sculpted areas: the big divot at the bottom of the top piece, and the sill. Note that the patching pattern along the right side of the left piece reveals the wood grain. It also reveals something about the structure of wood.

As you know, wood's grain comes from its growth rings, the concentric rings of growth running along the length of a tree trunk that record the age of the tree, one ring per growing season (they of course run along every limb as well). The wood that comes at the beginning of the growth cycle is called earlywood; the wood that comes later is called latewood. The previous sentence seems comically obvious, I realize, but I just follow the facts where they lead me, and damn the torpedoes.

Latewood is stronger and denser than earlywood, making it more resistant to weathering, Where the wood is cut perpendicular to the grain, this gives weathered wood a grooved appearance, like an old 78 RPM record; where it is cut along the grain, it gives the wood a wear pattern like the one revealed here in the putty: wide craters with narrow bands of high spots in between.

Here's another angle on the sill:

I had a little trouble catching this in a picture, but I've established the basic line of the completed sill reconstruction; now, it's just a matter of filling in the low spots, a simple task, and building up the angle at the junction of the two planes, a tricky one. The angle is tricky because it's hanging out in the air, giving nothing for the putty to grab on to. Thus, I have to try to slide it off the knife in the proper position along one plane, letting it harden, sanding it to profile, then filling in the resultant gap along the other plane. This is not too hard with the vertical plane, because I can pull the knife away from the junction, allowing the putty to build up like a stalagmite. It is however a more complicated task with the top, sloping plane, because I have to pull the knife toward the junction, dragging it along the edge of another knife held flat along the vertical plane at the proper height. That's not so hard, but then I have to slide the vertical knife down, which invariably pulls the putty down with it, and sometimes right back off again. Whatever happens, I have to let it harden that way, because to fuss with it will only make it worse. The bottom line is that it takes several passes to complete, and I end up sanding off a great deal of putty in the process.

Here's a closer look at the top of the casing. First look at the top right of the photograph, where the errant nail drove part of the top piece down and splintered the end of the piece underneath. It's a bit hard to discern because there are so many colors going on there, but with the exception of the triple-bead profile at the top of the lower piece, the original profile is completely restored. This is why I was so happy the previous workman had preserved the splintered pieces, because I was able to glue thmn back in place and simply putty up the remaining gaps, rather than having to go through the struggle of re-establishing the angle out of thin air.

Now, let's look over to the left. As is painfully evident here, I'm having a great deal of difficulty re-establishing the horizontal plane along the bottom of the top piece. This is because I have to work along a narrow band hard against the vertical plane of the strip right behind it. I don't have a knife narrow enough to run along this plane while holding another knife against the front, so I have to pull a knife forward, and there's so little wood there that the putty doesn't want to stay where I put it. I thus have to help guide the putty with my fingers. When it hardens, I can't simply sand it flat, because I can't get a crisp angle at the back this way without sanding the rear piece out of shape. I thus have to take a wood chisel and carefully cut away at the putty to establish a straight, crisp angle back there.

A carpenter more skilled than I would undoubtedly have chosen instead to chisel out the gap so that it was straight and square, and then glue a new piece of wood in there to fill the gap completely. Then, he would have puttied the seam smooth. I, however, am far more confident in arriving at a satisfactory repair using putty alone. It may take a while, but I'll get it.

In the meantime, I offer the following picture of domestic tranquility for your enjoyment.

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