Status Update

I had a week off work, so I got to spend quite a bit of time working on the guitar build.  Not as much as I would have liked because of the missing band saw parts, most of which have still not showed up yet.  Here are some pictures:

I cut out the mahogany back with a coping saw and got the braces installed and shaped. The back braces have a slight arch to them to give the back a subtle curve. The strip running vertically is thin basswood.  It's light, but the grain runs perpendicular to the grain of the back.







Here are the top braces being glued in.  The clamping technique here is called a go-bar deck. (Be careful if you Google that or you'll find lots of go-go bars). I've seen lots of custom jigs for how to do this, but I just used a shelf over my workbench as the top.  The idea is to take flexible pieces of wood and wedge them between the top deck and the brace to be clamped.  This works pretty well.


Here is the sound hole rosette installed. I was able to cut a slice off using a table saw.  I think it would be a lot easier to cut with the bandsaw once I can use that. The two vertical lines you see are where the panels are glued.  I wasn't able to get panels wide enough to do the whole top in 2 pieces, so I did it in thirds instead.  The glue joint is tight enough, but the yellow Tightbond glue left a dark line.  On the final build, I'm going to switch to a white glue that dries clear, at least for any joint that will show.

Here is the neck carved and ready to install.  I actually did this part before I started blogging about it.  The neck is maple, which is available locally.  The slots for the tuning pegs would be a lot easier to do with a drill press, but I don't have one so I used a brace and bit with a 1/2" auger bit.  This worked pretty well, but the bit slipped a couple times on the first slot causing it to be less straight than I would like.

When the switch guard for the band saw showed up, I was at least able to cut out the guitar shape on this form. I don't want to run it too much without the lower tire, as that will dull the blade.
The turnbuckles allow me to spread the blocks apart to press against the sides.  Note that the left side is in the form now.  If I were to make this again, I would leave the inside continuous instead of making it 3 pieces on each side. Or at least make the blocks on the lower bout bigger. When building this, I planned to replace the hook and eye that came with the turnbuckles with carriage bolts.  However, I forgot that one side of the turnbuckle is threaded backwards, so the carriage bolts won't go in.  I just cut a slot in the blocks and slipped the eye end in.  I may epoxy these in some day.

This is my side bending pipe.  I was trying to come up with a way of using an electric heating element to heat the pipe, but the smallest one I could find was 1400 watts, which comes out to about 12 amps. I wanted to use a light dimmer switch to control the temperature, but I couldn't find one rated for more than 1000 watts.  I settled for the small propane torch.   I bent one of the practice sides that I bought from LMI.  It worked pretty well, but you have to go slow and take it easy to avoid cracking the wood..  It also turns out that I need to fill the bottom pipe with sand or something.  Otherwise, the torch blowing across the opening makes it resonate like blowing across the top of a Coke bottle.  Of course, the guys at the organ shop who cut the sides for me will probably read this and say, "Well, duh!".
Additional update:  I bent the mahogany sides that they cut for me.  I should have asked for them to be thinner than 1/8" because they wanted to crack at the waist, but I managed to get them to bend without breaking.  The practice sides from LMI were only .09". Soaking the sides also helped.

Band Saw

I now have a band saw.  Home Depot had a 14" RIDGID  band saw, but the only one they had was the floor model.  It was $50 off and came pre-assembled, so I bought it.  In theory, this thing can resaw material up to 6" wide.  While that's not enough for backs and tops made the usual way -- joined in the middle -- it's enough to make them in thirds. It's also useful for sides and cutting out the curves.

The problem with buying a pre-assembled saw is that you're assuming that whoever assembled it was competent and didn't end up with pieces left over that they just threw out.  I got the thing home and found that there's supposed to be a little plastic key that goes on the power switch so that unauthorized personal can't turn it on. Of course, if it's missing, nobody can turn it on.

Fortunately, I found a site on the internet that had the part, and it's only 89 cents.  Shipping was $10.  So I ordered 5 just in case.

Having ordered that, I checked out the rest of the saw to make sure it was setup right and the blade aligned correctly and everything.  Found several other parts missing, including the lower blade guide and the rubber tire that goes on the lower wheel. Arg!

I went back to Home Depot and asked if they could look around to see if the extra parts were stored somewhere. They couldn't find them, but they gave me an extra $40 discount which covered having to order the parts.

Building the Rosette

I've been working on building the rosette that goes around the sound hole on the guitar.  This turned out to be a rather challenging thing to build.  The inner and outer rings are multiple layers of veneer alternating light (maple) and dark (gum wood).  I found the gum wood at Hardwood Heaven, a local supplier of hardwoods.  Unfortunately they didn't have much of a selection.  They had one flitch of a burly maple, which I bought, but decided that it looked too nice to use someplace where you wouldn't be able to see the figuring in it, so I'm saving that for something else.  I ended up using a package of 3/4" wide edge banding with a heat-activated glue.  This actually worked out pretty well.  

The form is a 4" diameter circle cut out of a 2x6 using a hole saw.  Since the outside diameter of this block is actually smaller than the sound hole will be (it's the inside diameter of the hole saw and the sound hole will be the outside diameter), I first glued a few layers of cardboard around it to build it up.

After gluing the inner rings, I tightened a couple of hose clamps around it and let it dry.  The center rings are made up of small pieces of wood.  I would have liked to have been able to cut these a lot more accurately than I did.  They're not as uniform as I would have liked. It also didn't occur to me at first that the ones on the outer ring would need to be a tiny bit wider to account for the fact that the circumference is longer.  The circumference of the outside of the ring is longer by 2 × thickness × π. If the pieces are 1/8" thick, that works out to more than 3/4".  Divide that by the number of pieces (45) and you end up having to make them just barely wider.  If you don't, the pattern will eventually not match up.  The angles have to be different too.  It's a 30° angle on one side and 35° on the other.  They had to be glued on a few at a time or else they kept shifting. Once the inside row was glued, I clamped it and stuck the whole thing in a 300° oven for five minutes.  This allowed the glue to soften and the clamps could be tightened some more.

Next I added the big carriage bolt you see in the picture and chucked the whole thing in a drill.  With the drill on a low speed setting, I held a rasp to it to smooth out the rough edges. Then I added another light strip (hard to see in the photo) and repeated the whole process for the outer rings.

First Guitar Build Update

For the fist build, I wanted to try the techniques needed on wood that I could get locally.  Menard's (a Home Depot like place) has mahogany in stock.  I tried resawing some on a table saw, but I couldn't get that to work.  The blade won't go more than about 1.5", so even if I turn the wood over, I can't resaw anything wider than about 3 inches.

I was talking with Mark, the accompanist at our temple, about this project.  Mark just happens to be one of the vice presidents of a local company that builds pipe organs, He said that they had just finished building an organ cabinet out of mahogany and thought they might have some scraps and the tools necessary to do what I needed.  Two weeks later, he brought me some mahogany pieces for the sides and back.  Thanks to Mark and the crew!  (I would name the company, but I don't want them to get a flood of requests for this sort of thing)

The back came as two book-matched pieces.  When I held the pieces together and held them up the the light, you could see a bit if light, so it wasn't a perfect joint.  The crew who sawed them up may have run them through a jointer, but I had let them set for a week, so the wood had time to relax and it wasn't 100% perfect anymore.  I had found a YouTube video about using a "shooting board" to plane the edges perfectly for joining.  I built this jig and tried to improve what I had.  It turned out not to work so well.  The plane kept catching and making it worse.  I gave up on that and used sandpaper wrapped around a long level, which worked a lot better.

The back is glued-up now.