Mon, 24 Jul 2006
We’ve had some discussion on this topic over at the Everything dulcimer forums about how to join two thin pieces of wood. I wanted to post a quick pictorial on how I do it so I could share it with the luthier community. This is a method I learned from Bob Mattingly many years ago and I use this technique on dulcimer tops and backs as well as guitar tops and backs. First, set up a shooting board by clamping both sides of the top to a long board. The two sides that are to be joined are on the right.
Then get a good, sharp joining plane and plane the edges straight.
Plane until you get curls from both pieces of wood
Hold the pieces together to see if there is ANY light between them. If the seam isn’t
perfect then work on it until it is. I use a long level with sandpaper glued to one side to
clean up the edges until they are perfectly flat.
Now get your workboard out and cover it with plastic or wax paper so the glue
won’t stick the top to your workboard.
Set the top on the workboard …
and then tap in some finishing nails such that they are flush against one of the outside edges of the top
Now find yourself a piece of scrap wood to use as a temporary spacer. This piece is actually a bit too big
for what we’ll use it for.
That spacer is used to make a “tent” of the two pieces of wood.
Keeping the center seam tight in the “tent” tap in some finish nails flush against the other outside edge.
Notice that the nails are NOT going through the top. They are flush against the top.
Remove the spacer block. Put glue on the edges to be joined and then press the two pieces flat against your workboard.
The tension created by the “tent” is the clamping force that keeps the center seam tight.
When I did a “dry fit” I found that this size tent created too much clamping pressure so I went ahead and
found a smaller piece of scrap, I pulled out the nails and reset them without quite so much pressure.
Wipe off the excess glue with a wet paper towel and then lay down some plastic or wax paper on top
of the boards and wieght them down with something heavy enough to keep the tent from popping up.
I use a couple of hand planes.
That’s it. It works great and when your done you have a very tight seam and your two pieces of wood will be
absolutly flat to each other. I’ve never had a center seam open up.
Here’s the proof of the technique. This is the back of a purpleheart dulcimer. There’s a center seam in this
photo that was done using this exact method. Can you see the seam?
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