Monday, 25 April 2011

Disembodied hands

So, the bars are glued onto the underside of the what?

Now things start to move along relatively quickly.  If lute making was an action movie, the point we're at now would be at the beginning of a (really slow) car chase.  In a reasonably short time, a number of pieces are going to be fitted together, and things will soon begin to look an awful lot like an actual lute.

The first thing to do after the main bars are on is to glue on a number of small bars that support the delicate pattern of the rose.  Depending on the pattern, there might be a half-dozen or more placed strategically behind the rose:

Notice the ends of these little bars--I've scorched them with a hot iron.  This is because of another amazing property of hide glue.  While normally it takes a few minutes to set, and another few hours to dry hard, hide glue will crystallize instantly if it is scorched.  So, rather than clamping each rose bar separately, all you need to do is brush some hot hide glue on the bar, stick it down in place, scorch the ends, and voila--the bar is stuck down securely, effectively clamped at each end, and the hide glue in the middle can dry naturally over the next few hours.  I ask, is there anything hide glue can't do?

The larger bars have been glued on over-size, so the next job is to plane them down to their finished profile.  Here are a pair of disembodied hands doing just this work:

The bars are chamfered along their tops, and their ends are given a long, gentle scallop.  Here's what the 8 course belly looks like with this trimming done.

If you look closely at this photo, you'll see the outline of the lute's body that I craftily drew onto the belly just before gluing on the bars.  At this point,  I can trim back the ends of the bars until they are just inside that line, and begin the process of fitting the belly into the body of the lute.

I won't rely on just that line when I'm fitting up the belly to the body, however.  In fact, I'll spend a lot of time at the bench trimming bar ends, fitting the body over the belly, looking at the outline of the lute and the curve of the outside rib, making sure I've got a smooth shape all the way around.  This trimming and testing is the only way I have of making sure I'll have a good, smooth, aesthetically pleasing outline when the belly is eventually glued in.

Right now, though, I'm most concerned with getting a true and accurate fit because I want to find out where the bridge will be located (and glued) on the belly.  Of course, I have a theoretical location in mind where I hope the bridge will go--it's on the detailed drawing I made of the lute long before I started to build it. Theory and reality don't always exactly match up, however, especially when putting together such a complex machine as a lute. 
So what I do is carefully fit the belly into the body, and tape it securely in place.

Then I lay my detailed layout drawing on top of the lute, and see how theory and reality match up.

Hmmm... looks good.  Looks very good, in fact.  I flatter myself (and invite the wrath of the gods of lute making) by telling myself I must be getting good at this.

In fact, all three of the lutes in this batch look in very good shape.  I'm able to mark the location of the bridges on their respective bellies by using only a couple of pricks of a sharp pin.  Then, in a flurry of work and concentration, and following a carefully worked-out and time-tested routine, over three successive days I glue three bridges on three bellies.

If I've done my work correctly, I've created a glued joint on each that will withstand the combined tension of as many as a couple of dozen strings, and transmit the vibrations of those strings to the soundboard as efficiently as possible.

As with all of this, the proof will be in the playing... but for now, I'm very happy with the progress of these lutes.  


Sunday, 17 April 2011

The Innards

At the risk of stating the obvious, I have found that the work of making lutes consists largely of making things.  Cut a rose, carve a bridge, turn a set of pegs--there are just a lot of different items that need to be produced.  That's good: I like making things, and each day in the shop is different, so there's never a dull moment.  That being said, however, you can make a lot of things without actually making a lute. There comes a time in the process when you have to start putting some of these things together.

Most of the time, that will involve using hide glue.  Perhaps you're familiar with this stuff; if not, I'll briefly acquaint you.  

Hide glue is made from the hides and connective tissues of certain animals (and yes, horses are prime candidates for this job).  It's been used by woodworkers for thousands of years, though not too many woodworkers use it these days--synthetic glues are more convenient and readily available.  (Incidentally, my mom tells me that my Swedish great-grandfather, a woodworker who came to Canada in the early years of the last century, used to make his own hide glue.)

But nothing beats hide glue for putting together a lute, for a lot of reasons.  It dries hard and makes a very strong joint, yet with a little water and heat (and time, and much care!), any joint on a lute may be reversed.  This is especially important where the soundboard joins the body.  Most lutes will, at some point during their lifetime, need to have the soundboard removed for repairs or action adjustments, and this difficult job is made a little easier if hide glue's been used.

Here's what it looks like in granular form, straight out of the bag.

Put a scoop of this stuff in a baby-food jar, add a little water and swish it around.  Leave it for an hour or two to let the glue absorb the water, then heat the jar in a pan of water.   The glue becomes liquid, and it's ready for use.  So get to work!
Today's job is to glue bars on the underside of the soundboard (or the belly, as it's called in the trade).  These bars are "innards" of the lute, and they function exactly the same way your innards do: they provide strength and structure, and ensure that the whole body functions harmoniously (and keeps you singing sweetly....)

The barring patterns for these three lutes are all basically similar, but there are some important differences.  I don't want to launch into a big discussion of lute barring here--I'll only say that within some basic parameters, there are just about endless possibilities for varying the height, thickness, and location of one or all of the bars, and each of these adjustments will have an effect on the sound of the lute.  

I've devised a barring scheme for each lute, based on historical evidence.  I've selected barring material from my stock of fine European spruce, creamy-white, close-grained and stiff, and cut and planed each piece to the correct dimension.  My hide glue is ready, heated to the correct temperature and diluted to the correct consistency.  I'm just about ready to go....but wait.

In a minute, I'm going to be gluing a dozen or so bars to the underside of the belly--that's going to involve a lot of clamping.  I don't have enough clamps in my whole shop to do it, and even if I did, I couldn't put all those clamps on the belly at once--there just wouldn't be room for them.  I suppose I could glue a few bars down, let the glue dry, then glue on a few more, but the whole job would take days.  At the same time, gluing a few bars at different times and in different shop humidities might introduce tensions into the soundboard that could eventually end up cracking it, and causing a lot of other problems.  So what's the solution?

The solution is a contraption called a go-bar deck.  Lots of lute makers and guitar makers use them, and they are a miracle.  Not the simplest thing to use--it gets to be quite a forest in there toward the end of the job, and the one thing you do not want to do is accidentally nudge one of those sprung bars--but once you are ready to start the job, it's pretty much guaranteed that in an hour or so you'll be done, and all the bars will be glued on at the correct humidity.  Here's what it looks like, fully-loaded, all bars glued and stuck down, held in place by flexible bars made of red oak.  (My glue pot on the hot plate is just on the left.)

Here's a closer shot:

And one from the back side, showing a better view of the belly and bars.

This go-bar deck was kindly lent to me by Grant Tomlinson. (His workshop is just down the hall--we'll go visit him and see what he's been up to in a future post.)

So that's another big job done.  I'll leave it to dry overnight, then next morning carefully remove the go-bars and set the belly aside.  Then later on in the afternoon, I'll glue the bars on the next belly... and the next day, glue the bars on the third. 

Here's what one of the finished products looks like--this is the 13 course belly with bars glued on, just after coming out of the go-bar deck.  The bars still need to be trimmed and given a final shape, then the belly will be fitted into the body.  Exciting stuff coming up!  See you next time...