Saturday, May 14, 2011

A Re-Epiphany

Yesterday I was talking at length about the difficulties I was having in getting the putty to come off the knife and stay where I put it. I mentioned that maybe the problem was just that I hadn't gotten my chops back up yet. That happens to me a lot when I get back to doing something I haven't done for a while, whether it be puttying or removing noise from a recording: I'm constantly finding myself having to re-learn the finer points of some procedure that have slipped my mind.

As it turns out, this was indeed the problem. It seems that writing everything down as I did flogged my memory overnight, because today it was all back in my brain as if it had never been gone. I guess I should start writing down my noise-removal procedures as well, next time I re-learn then.

The reason I was having trouble getting the putty to stick was because I wasn't cleaning the work surface off with alcohol first. No matter how thoroughly you dust, still a fine layer remains that must be washed off; alcohol is the best thing to use in this case because it evaporates quickly and leaves no residue that would inhibit adhesion or curing of the epoxy.

I also forgot that once I apply some putty, I need to scrape the remainder off my knife with another knife before taking up more putty so that it is all massed at the tip. Any putty remaining further down the knife is liable to stick to putty already applied, pulling it back off the work.

Another technique that came back to me as I worked was my method of building up junctions between planes. You will recall that I discussed pulling the knife down along the vertical plane, letting the putty build up like a stalagmite. The missing step here is to then take another knife held sideways and flip it down onto the other plane, then press down and slide the knife away from the junction. This pushes the putty out a bit at the junction, helping to ensure coverage of the desired line.

Here are the results of my newly-restored chops on the sill, before sanding:

As you can see, I've made a huge jump towards completion, but given the mess I had already created, it looks as if I'll still have to build up the top plane more.

By the time I got to the mess on the top piece, I was on a roll, and came up with a new trick: I held a straightedge along the patched area, lining it up on both sides with the undamaged edge. This showed me the line I was building to, and allowed me to see where I had built the putty up past it. I then held the straightedge firmly as I sanded back to that edge, being careful to sand level and just a hair forward of the backing piece. It was then laughably simple to fill in the now-obvious gaps. Here is the result:

And here's another shot, looking straight on from the front:

What looked nearly hopeless yesterday now looks nearly completed today. A little sanding, a little carving at the back, and I expect this will be done.

* * *

Meanwhile, back in the garage, I began to prepare the apron pieces for re-attachment. The first thing I needed to do was strip the paint off of them, because over the years paint had built up on the edges and in the back, obscuring the profile and preventing its lying flat against the backing piece. I didn't want to sand the paint off, lest I distort the profile of the wood. In the process, I broke one of the aprons in several places. As I said, this old wood is extremely fragile, which is why you want to mess with it as little as is necessary to do an adequate job.

After I finished stripping, I glued the apron back together, using a special PVA glue, similar to Elmer's white glue but specially formulated for wood. I used this glue rather than LiquidWood for several reasons: first, it's foolproof, needing no induction period; second, it sets up in a half-hour; third, I don't have to waste any excess as I would with the epoxy, and finally, I can touch it without worry, so I was able to coax the pieces into perfect alignment as I tightened the clamps without having to try to feel through gloves. This glue really is a delight to work with, and the right clamps really help, too.

You will notice one remaining piece at the top; the profile of the piece is such that I can't clamp it, so I will attach it later with cyanoacrylate glue, a special type of Super Glue designed especially for wood that is thicker and sets up in a minute, rather than a few seconds. I can simply hold the pieces together tightly as the glue sets. So you see, as useful as LiquidWood is, there are times when other glues are more suitable.

After my reminder of just how fragile these pieces are, however, my next step will be to saturate these pieces with LiquidWood so that I will have no further worries of breakage.

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