Thursday, April 23, 2009

Gluing the Soundboard - Again

Thursday, April 23, 2009.

As I had hoped I got all the repair blocks glued on last night.

And this evening when I got home from work, I started by preparing the mating edges of the soundboard halve for gluing. For this prep I decided that I needed to sand the edges smooth. To do that, I needed to sand the entire edge at the same time and that required as flat of a surface for the sandpaper as I could find. Not having anything better, I took the pane of glass that I originally purchase for use when sharpening my planer blades. I took off the sandpaper pieces that were already taped on and then taped on a full sheet of 350 grit sand paper. I then took the first of the two soundboard halves and, holding it by the repair blocks, began to sand it gently length-wise.

After sanding for a few moments, this was the pattern left on the sandpaper showing where the contact was.

Clearly, my joint was not as flat as I needed. Once I was happy with it, I moved to the base side. Here is its contact pattern.

Even worse!

Once I had sanded both halves to where I was satisfied that they were as square as they would get, I switch over to 600 grit paper to finish. Holding the two halves together up to a light showed no gap. Woohoo!

The next step, of coarse, was to dry clamp the two halves together as practice and to verify that everything would work out once glue is applied. Good thing I did. As it turns out the spring clips are way too strong for this application as they come out of the box. As it happens, two of the repair blocks broke of under the pressure. So, to correct this problem, I chose to “spring” the clips to weaken them. That was a simple process that I was able to do by hand.

Once sprung, the clamps offered a small but sufficient force and I was ready to glue.

I am pretty pleased with the way this all seems to be working out but it is difficult to be sure since the glue squeezed out both the top and bottom of the crack. Tomorrow will tell the tale.

No comments: