Chapter 13

Gluing up the Soundbox

I spent several days searching through books of Celtic borders and designs.  I finally located a basic design that I was able to modify here and there to suit my needs.  After generating a pattern and transferring that pattern onto the face of the soundboard,  it was time to start burning.

    This is one of my favorite parts of a project like this.  I get to bring the work piece into the house, make myself comfortable at the dining table, and burn all evening long in front of the television.  As long as I try to keep the area relatively clean, "SWMBO" * doesn't really mind.  I use an electric, temperature controlled wood burning pen with a variety of different tips.  Specifically, it is a "Detailer" by Colwood Electronics of New Jersey.  I first started burning with a standard, solid tip, single temperature burning pen, and it served me well for many years.  After purchasing my Detailer", I found I wasn't using my old, soldering type iron much anymore.  So I gave it away to the son of a friend of mine who had expressed an interest in pyrography. 

    First, I used the sharp, knife point (or skew) to lay out the lines of the knot work.  Each pyrographer has his or her own techniques, and in this step I like to burn the basic outlines hot and deep.  I started in the lower corners, and burned in the designs on both sides.  When I stood back and looked at it from a distance, it seemed "bottom heavy", or out of balance.  Then I decided to add the knot work near the top of the soundboard.  After doing that, I stood back again for another look.  At this point, the pattern looked balanced, but very subdued.  I wanted the artwork to stand out and be seen.  I decided a bolder look was called for, so I shaded in all of the interior spaces of the knot work.  The photo on the right shows the end result of about 2 evenings of burning.  After completing a piece like this, I like to go over the entire work with very fine (220) sandpaper.  This smoothes out the surface, and removes any overburn, or scorching marks from the heat of the iron.

    The fun and games with the wood burning pen are over for now, and it's back out to the shop.  In this photo, I have all of the pieces laid out ready for glue-up.  I've got all of the clamps I'll need handy, and nearby I've got a box of small scrap wood blocks.  These will come in handy later.  The two long strips of wood in the foreground are the internal glue strips that will reinforce the joint between the soundboard and the sides of the soundbox.  They are cut from Maple, 1/4" X 3/8", and cut long enough to go from the top block to the base.

    Now it's time to start working fast and sure.  I've got to get all of these pieces glued, positioned and clamped in place before the glue begins to harden.  This is why it pays off to have all of the pieces together and ready, clamps handy, and anything else I might need within reach.  I start by applying a thin bead of glue into the grooves that will accept the edges of the soundboard.  Here I'm careful to apply the glue to the INSIDE edges of these grooves, away from the front of the harp.  The idea here is to minimize glue squeeze out on the front, or appearance side of the harp.  I quickly applied glue to the grooves on both sides of the harp, and then I used a small sliver of wood as a brush to distribute the glue evenly along the length of the grooves.

I quickly slide the soundboard into place within the grooves, and push it up, towards the top until it gets tight.  Fortunately, when the soundboard got tight in the sides, the top of the soundboard was also flush with the top of the top blocks.  I just love it when a plan comes together.

'

Just for now, a couple of bar clamps pull the sides in tight, and hold the soundboard in place while I glue in the bottom, or base of the harp.

    Still working as quickly as I can, I apply glue to the 5 sides of the base, and clamp it in position.  Here it's important to make sure that the base is snugly against the bottom of the soundboard, and nested down into the sides and back pieces as well as possible.  Excuse my shoulder in this shot.  I need to have a word with that photographer.

    Quickly, but carefully, I flip the assembly over onto it's face, and apply glue to 2 adjacent sides of the reinforcing strips.  The large hole I put in the base of the harp makes the insertion of these long strips easy.  I locate these strips snugly into the corner between the side of the soundbox, and the back of the soundboard.

    In this close up shot, I've tried to show how I use some special clamps I've developed for awkward applications like this.  These clamps are just thin pieces of spring steel, cut to various lengths, and sharpened on both ends.  I push one sharp end into one of the bracing strips, and then flex the clamp over to push the other end into the opposite brace.  The spring tension of the clamps pushes the braces snugly into the corners and holds them there.  Because of the tapers that run the length of the soundbox, it's now easy to find various pieces of scrap wood to locate here and there within the soundbox.  Pushing these blocks up into the taper provides additional clamping pressure to make sure that the soundboard is tight against the front edge of the grooves, and that the braces are tight against the sides of the soundbox and the back of the soundboard.  You were wondering what that box of wooden blocks was for, weren't you.  Now you know.

    Now I want to let this whole assembly set up well before I remove any of the clamps.  Later on, I'm going to use the same procedures to add small braces all around the base of the harp, inside the soundbox.  These will reinforce the joint between the base and the soundbox.

    The next step will be to "fine tune" the joinery between the 3 main components of the harp.  This is going to require a lot of detailed hand work.  I plan to carve and chisel the joints for a perfect fit.  Then some final shaping and sanding will be required before I can bring the whole harp into the house for more fun with the wood burning iron.

Until next time.

* SWMBO  For those of you who may not know, means "She Who Must Be Obeyed."  No offense intended to those of you who prefer to believe it means "She Works My Butt Off!"

On to Chapter 14

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