trim the top and start on the fretboard

 Took the top out of the clamps and proceeded to sand the overhang back to the body.  Also sanded a couple dings on the top, that Western Red Cedar is stiff but has a soft surface.

Then it was time to lay out the fretboard across a nut stand-in, and the bridge.  I took a number of measurements and then it was time to cut.  This was a picky operation as it needs to fit tight to the neck but also extend over the top plate of the body for a bit.

Some hand sanding on the bottom of the "ledge".  I did this on the edge of the table saw.  This gave a nice flat surface and a good 90 degree angle to hold things in alignment.

I needed to cleanup the end of the head plate towards the nut.  It was straight but not quite perpendicular.  Got it squared up with an exacto and a chisel.  My design requires a 1/2" piece of maple on the headstock side of the nut so I cut and fitted that.  The fretboard will be maple to match.  Nothing glued up today, I have a bunch of work to do on the fretboard still.  The neck will have to be thinned down a bunch too now that I have a fretboard thickness.

Starting to see the end of the tunnel!

Brian

Time to glue on the top

 I did some clean up on the back stripe first.  I haven't touched it with sand paper yet.  I used a card scraper on the surface to get the zipper stripe flush with the back plate.  I love this wood!  I then used a rasp/file to bring the edges back flush with the sides.  I won't do any sanding until the top is also attached and flush.

I then did a bunch of looking and reflecting on the top, and decided it was good to go.

I signed the under side where no one will ever see it.  Then I glued it up and "clamped" it just using weight, but the bottom/sides/top are clamped between 2 matching radius dishes so they have even pressure all the way around.

Then I spent a little more time working on the bridge.  I don't know final dimensions yet for the bridge but I'm getting it closer.  

Once the top glue is set up I can start measuring for the nut/fretboard/bridge(saddle) dimensions.  When I know those dimensions I can get to work on the fretboard, which I'm kind of excited about.  

Hope I can pull it off!

Brian

my mistake is now a feature!

 So as I noted previously, I tried a new glue on this build for the top and back plates.  It was a water proof glue meant for boat building.  Since I force my plates from flat to hemispherical I thought that maybe using heat and moisture might help the plates conform with less stress.  However, instead the glue just failed and let go, leaving the back plates hemispherical but not glued together.  They also would NOT go together without re-jointing.  So, I re-jointed and tried to glue them together, but with curved surfaces there was no good way to clamp them up and this is what I was left with.

I could have started over with different wood but my other option is to do something with the gap.  As seen in earlier pictures I glued in a support strip on the inside covering the gap.  This is a normal step but I did use a wider strip than normal.  Then, with the back glued to the body it was time to fix it.

I knew that I wanted to install a "zipper" to cover this.  Here is what I am calling a "zipper", it's a piece of inlay used on guitar backs or as purfling around the edge binding, etc.

Next step was a jig to guide the router while routing a straight groove across that curved, hemispherical surface.  I had the jig I'd used to create the radius dishes so I grabbed the guides that matched the 8 foot radius.  I cut square blocks that matched the width of my router base and nailed them between the radius guides.  Then these got clamped across the back of the uke body.

I used a speed controller on the router to slow it down quite a bit and proceeded to cut the groove.

Then test fit the zipper.

While most of the groove was a good fit there were a couple TINY gaps along side the zipper.  I grabbed a bit of sawdust from sanding these plates to thickness and proceeded to glue the zipper in place and then rub the sawdust into the gaps where the glue had squeezed out.  The masking tape should help a lot with cleanup later.

The zipper is proud of the surface by about 1/32" so the card scraper and sand paper should clean things up nicely after the glue is dry.  Looks like my earlier mistake is now a feature!

Brian

brace carving complete, time to glue the back on

 I didn't post yesterday but I carved most of the braces.  Here are some pics.  

First pic is showing how the bridge will be supported by the braces (but obviously on the outside).

Next pic didn't get focused correctly but maybe you can see how the straight edge reveals about a 1/8" gap on each end due to the curved radius top.  This is hemispherical so round like a ball in all directions.

Started carving in the center.  Tapering from the sides and reducing the height.

The ends sticking out all get tapered and reduced.  This is kind of by gut feel.  You want to reduce the mass to help it vibrate but also stiff enough to maintain it's shape and not collapse.

Here's my best guess right now.  I can still take off more up until I glued it onto the body.  Occasionally during carving I pick it up by a corner and tap on the top in various places.  You can start to get a feel for how responsive it is... hopefully.  If it sounds dull, might need to remove more.

I trimmed the top a little closer to the line and marked the top and body on the outside to help align it when it comes time for glue.  I also wanted to make sure the sound hole is lining up with the neck.

And finally, I glued the back into place.  I'm doing the back first since it will be visible through the sound hole and glue cleanup will be easier.  I think I'll give the interior a single coat of finish before I button up the top.  Note, the back book match didn't pull together tight enough when I re-glued it (noted in an earlier blog) so I'll need to make a jig to allow me to route a 1/8" slot up the joint to install a "zipper".

It's getting there slowly but surely.

Brian

glue the top braces

 First up before I forget I signed, dated, numbered the back plate.

Then I cleaned up the sound hole brace or patch.  I used the Dremel with a small sanding wheel.

I cut the sound hole into the top.  I used masking tape front and back to help control any tear out.  Did some light sanding of the edge, then glued the brace/patch into place.  I put the top plate onto the radius dish to allow for the slight 25 foot radius curvature.  Then I glued and clamped the ring using the go-bar deck with fiberglass rods for clamping pressure.

Note how I put the sides in before clamping.  This allowed me to position the rest of the bracing accurately without the sides glued into place yet.  I think I used every rod I had!

When the glue is dry it will be time to carve those braces to lose some unnecessary bulk and weight.  They'll also look a lot better.  Funny how I want them to look good when the only way to see them will be putting a mirror or camera down through the sound hole.  But, it's one of those OCD things and the conviction that if I'm going to do this luthery thing then I want to do it "right" as much as possible and be proud of my builds.

Brian

layout of the top plate

 Time to start looking at the top plate.  I googled ideas for top bracing patterns and picked one out.

I sawed a bunch of brace wood from my stock on hand.  It's all about 1/4" x 3/4" now with lengths up to 22".  I have another 1x piece that can be ripped later as necessary for future builds.

I also grabbed a 1/16" thick piece of wood 3" wide and cut it square.  I took that to the drill press and drilled a 2" diameter hole.  I enlarged that hole by about 1/8" at the spindle sander and then took the piece to the jigsaw to cut it into a circle.  Did a little cleanup at the disk sander and it's ready to be a backing support piece for the sound hole.  The sound hole will be 2".  I also laid out on the cedar top the location I decided on for the sound hole.

I also laid out the location for the bracing.  The feet of the bridge will sit on the intersection points of the H bracing.  The bracing will get notched and the bottom radiused to 25 feet to keep a tiny bit of arch in the top for strength and tension, which helps with the sound.

I sanded the braces to the 25 foot radius right on the radius dish, which has sand paper glued to the surface.  Since I need to ensure the entire bottom gets sanded to shape it's easiest to draw a pencil line on the bottom surface and sand until it's gone.

Nothing is glued yet, and the braces will need to be carved to reduce weight and get a "tap tone" that I like.  It's kind of like, carve a little, tap the top to get an idea of resonance, then carve a little more and repeat until you're happy or you maybe start to lose tone.  Then STOP!

It's starting to look like an instrument and getting kind of exciting!  Plenty more to go though with the glue up, fret board and neck work, and finishing; but I'm starting to see the finish line.

Brian

bracing and sanding

 I cut my back braces to fit around the back reinforcement seam and glued them up in the go-bar deck.

The back is sitting in the radius dish to support the curvature and the curved braces are fit into position and held tight by the fiberglass bars.

I worked on a couple other wood work projects while the glue set up and then set about sanding the plywood frame to match the radius dish curves.  This is necessary so the curved back plate and the surface it gets glued to will match and give a good bond.  Yes, leaving everything flat is much easier, but the radiused back "feels" so much better.  It also allows for the top/back plates to flatten rather than split as they shrink in the low humidity of winter.

Note the gap between the ply and the dish in the 1st pic and it's gone after sanding for 10-15 minutes.

Here is the side/neck assembly sitting on the plate.  Just checking the fit now.  I won't glue anything until I've braced and fit the front plate.  I sanded the ply for the front plate to a 25 foot radius (the back is an 8 foot radius), just don't want that much curve on the top.  The top needs to move, vibrate, and be driven by the strings kind of like a speaker cone.  The back needs to reflect the sound from the interior out the sound hole (which I haven't cut yet).

I also trimmed the excess on the headstock plate but alas, no picture today.

Brian