Saturday, March 14, 2009

Carving the Soundboard

Saturday, March 14, 2009.

This week I started on my soundboard. As you might recall, I purchase my European Spruce Top Wood from Stewart-MacDonald back in January and only now have I really been able to get to work on it. I may well have purchased a bit early, as I speculated back then, but I’m certainly glad to have it now.

It arrived as a mostly precut, book-matched pair of pieces (see my post “Arrival!” in January for pictures) that I finished cutting in half using a handsaw. Next, using my hand planer, I planed the freshly cut section of each of the two halves flat. Then, using my truing board, I dressed the mating edges of each half in preparation for gluing. Below are the results of my truing process.

I was pretty impressed with the final results from the truing process and found that holding the two pieces together up to a light, there were no gaps. Not too bad, I think.

One note - If you choose, as I did, to make the top guide of your truing board from plywood (and I guess this would hold true regardless of what wood you choose), be sure to sand down the very top edge, not so much to effect the squareness of the truing edge, but just enough to get rid of any splinters that might be there. I neglected to do this and ended up with a pretty good sized splinter in the base of my thumb. The price of getting excited, I guess.

So here is the soundboard while the glue is setting. I used my 192 gram strength hide glue for the joint and really like the results.

After letting the glue dry overnight and most of the next day, I used my trusty hand plane again and got the interior surface nice and flat. I would have preferred to use a powered planer for this, but I don’t have one (yet) nor do I know anyone who does. I am really quite pleased with how flat I was able to get it, though, with the hand plane.

Next I traced the finished outline of the top onto the interior surface of the wood using my acrylic template.

MISTAKE #3 (well, really close anyway): As I began to carve, fortunately no more than just the cavity you see in this picture, I realized that I had traced the outline UPSIDE-DOWN. Had I not notice this, I would have ended up making #1 a left-handed mandolin! But because I was so early in the carving process, I was able to erase my outline (done in pencil, thankfully) and re-trace it and continue.

I decided to do all my soundboard carving using hand tools rather than trying some of the power tool methods I have read about (drill press, router, etc.). I did this mostly because I already have a pretty nice selection of woodcarving tools that I am pretty comfortable using and, well, because I don’t have most of the other types (yet). For the soundboard, I am pretty happy with this decision. It is pretty easy to do, goes pretty quickly, and I really like the feel.

As I carved and as Mr. Siminoff recommends in his book, I used my soundboard gauges regularly as I carved to make sure I didn’t go too deeply, too often.

Here are some more pictures of my carving process.

In this picture, you can see I went ahead and trimmed off most of the excess material around the edges. I did this in preparation for starting on the top side.

It may not be really clear from this photo, but I missed on my depths a bit in a couple of places (too deep mostly on the edges). I am hoping this won’t affect the overall product too much, so I am going ahead with it anyway.

Something I found rather interesting was an effect of lighting. All through my initial carving, I worked in my room under pretty normal light. Turning the part back and forth as I carved (I did not have my piece bolted to the bench) and feeling the surface with my hand as I went, I was pretty happy that the surface graduations were pretty smooth. After I got far enough along, I took my soundboard downstairs to shamelessly showoff to my wife a little. At this point it was early evening and the light at her computer where she was sitting was relatively dark so, when I turned the piece to get better lighting on it, the shadow effects from the dimmer light really showed all of the imperfections I had been unable to see before. The thing looked horrible (she ooo’d and aahh’d, anyway - she is so sweet). Now that I knew, I took it back upstairs and commenced to work some more, this time in low lighting. This worked out pretty well.

One of the things I read about in several places was that other (real) luthiers use “scrapers” to smooth the surfaces of their soundboards and backs. At first I wasn’t too sure about this but as I go closer to my desired surface heights I found that my woodcarving tools were just not right for the job and that sandpaper wasn’t doing it, either. Because I didn’t have any scrapers in my toolbox, I decided to make one myself from an old, large wallpaper trowel I hadn’t used for years. After cutting the metal blade off of the trowel handle using an angle grinder with a cut-off blade, I shaped one edge of it to rough shape with my belt sander and the finish-shaped and sharpened it with a hand-file.

Talk about a handy tool, this thing rocks. I used it not only to smooth out the obviously rough areas, but also to “plane” off larger areas that were just a bit too high. I love it. You can see it in the top right corner of the picture below.

This picture shows where I have traced an outline on the top side of the wood and an edge line around the perimeter in preparation of carving on the top. I also show the templates I will use to gauge my progress on it and my scraper.

Here is a closer look at the edge line I drew. By measurement from Siminoff’s drawing, the edge width should end up being just under 3/16” thick. To mark this on my wood, I found that my mechanical pencil, laying on the workbench, makes a mark just at 3/16” - good enough, I figure, to use for roughing the top surface.

Last night I spent about two hours rough carving on the top side. Here are my results, so far.

This picture shows how I am unintentionally “signing” my mandolin as I go. This blood is not from gouging myself with a tool, as you might expect, but from a small splinter that stabbed me in the finger while wiping away some chips from the soundboard. It was such a small stab that I didn’t even know it bled until I saw it on the wood. The wound had already quit bleeding by the time I looked. Oh well. Thankfully this blood spot will be carved off later.

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