Archive for January, 2009

Guitar 805 – Disaster Averted!

January 21, 2009

Here’s the charred walnut side which put me into a funk.


I was convinced that I was unable to discern the subtle difference between bending a side flawlessly and turning it into expensive firewood.  I thought it all through carefully and tackled a successful creation of two walnut sides bent properly and ready for putting in the mold.

I thickness sanded the remaining two (good) sides with a hand held belt sander from 4+mm down to 3mm.  Even with some difficulty keeping the belt on the sander, I was able to get those suckers down to the thickness I believed would be easily bent.  Also, I believed the order of the bender sandwich components would make a difference.

Disaster averted!  I have two perfectly bent walnut sides.

The sandwich order:  Mold/stainless/silicone blanket/parchment/walnut/stainless.


Also, preheating the wood before bending was acheived by clamping down the ends of the sandwich to keep the wood next to the blanket.


And finally, the right temperature:  not too hot (charcoal), not too cool (wood cracks).  I set the temp gauge to MED and let the wood sit in the clamped sandwich for about 2 – 3 minutes.  A meat thermometer stuck into the sandwich at the lower bout area showed the temp to be 290 degrees.  I don’t have any idea if the temp is accurate, but I now have a benchmark.  In that the bending was successful (no burns, no cracks), I have the sandwich configuration figured, a temperature benchmark, and I’m sure future bends will be mostly successful.


Guitar 805 – Deadline challenged

January 21, 2009

Yesterday, the replacement walnut sides arrived.  As you may recall if you are a regular follower of this blog, I purchased a bench top planer to use to bring down the thickness of the sides to at least 3mm.  The planer worked very well on spruce, but when I planed down the walnut sides I met with disasterous results.  The planer would have worked well on the walnut, even though it is a harder wood than spruce, had the side grain been consistent and in one direction.  The planer is a rotating drum of blades that cuts into the approaching wood in the opposite direction of the wood moving through the planer.  If the wood grain that meets the planed surface skews away from the entering planer blade, no problem.  If the grain points toward the planing drum, the blades will grab the grain (instead of shaving it) and pop off or break through the wood plate.

Here’s and example of a wood plate with grain all going in the same direction as seen from the side:

/  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /  /

If the wood is fed into the planer as shown, it will grab the top of the grain and pop off pieces.  If this piece were turned upside down or fed from the left, the grain as it meets the top of the wood would be leaning away from the cutting blades, and you get a nice smooth cut.

The problem with the walnut is that the pieces all have shifting grain direction, making the planer option disasterous down around a 3mm thickness.  Here’s what the walnut looks like, viewing from the side:

/ / / / / / / / / / / / / / | | | | | | | | \ \ \ \ \ \ \ \ \ \ \ \ \

As I mentioned, it works just fine down to about 3 or 3.25 mm.  After that, the above piece fed into the planer will get from the front through the middle then pop off the rest of the board on the left when it hits the first strong forward directional grain.

The replacement pieces seemed to have enough similar directional grain, so I hit the old planer again, feeding both pieces in, one after the other, and only taking off around .25mm at a time.  The results were excellent!  Except when I went from 3.25 mm to 3 mm.  I whacked off a piece from the leading edge.  I had just previously measured the 3.25 mm, examined the wood carefully, and smiled, said, “one more time”.  Crap.

The whacked off piece left just enough side remaining to qualify as a side.  I put it in the bender, cranked up the heat, and turned a nice piece of walnut into charcoal.  Two critical mistakes in the course of 1/2 hour.

Mistake recap:

1.  Using a planer to thickness figured hardwood.

2.  Trying to bend 3.25mm thick wood (which is highly figured)

3.  Placing the heating blanket on TOP of the wood and turning it up to 11.

Now I am in serious shit.  I have two unmatched but good pieces of figured walnut, one from each batch which are close enough in color and figure to be entirely appropriate for the guitar sides.  One is 3.25mm thick, the other, 4.15mm thick (both too thick to bend).  I will NOT put either of these pieces in the planer again.  I need to get them down to about 2.5mm and bend them properly with the heating blanket UNDER the wood, and the temp level to 5, instead of 11.  I have enough experience to (hopefully) execute the next bends properly IF I can get the plates thicknessed down to 2.5mm.

I can hand sand them, orbital sand them, or belt sand them.  I could buy a $700 drum sander, or I could get O.B.Williams to thickness sand them for me, for around $75.  I could (and did) call LMI and order a pair of walnut sides as emergency replacements in case my next steps fail as well.

So, I continue to learn a lot about my decision processing when I encounter problems such as these.  There’s my initial gut reaction which usually results in me trying to buy my way out of the problem with extra tools, supplies, or services.  When I can resist the initial gut reaction, I spend a lot of time thinking through all the possible next steps.  I got through my gut reaction around 10am today, and other than inquiring with LMI about walnut side availability, I did NOT buy any solutions (especially the $700 drum sander solution).  So here’s what I’ll do tonight, and I will aspire to being successful, and will not curse if not successful, knowing I have a backup plan with LMI.

1.  Commit to thickness sanding the remaining good sides using my hand held belt sander.  No matter how long it takes, I will work those puppies until they are no thicker than 2.5mm.

2.  Properly build the bender sandwich which keeps the tomato (silicone heating blanket) UNDER the wood.  From the bender mold out, the order will be:  stainless steel sheet, tomato, parchment, walnut, parchment, stainless steel sheet.  (I even drew a diagram on the side of my bender so I would remember, along with the caption:  “don’t cook the outside”.) .  Do NOT spritz the wood.  Subsequent reading suggested it was a no-no with figured wood.

3.  Don’t turn the heat dial above MED.  Don’t cook for more than 15 minutes.

4.  Draw the spring blocks slowly but don’t hover over any one spot.

If I fail, I will scream, and I will probably have bad dreams again tonight as I did last night.  Last night all my family, all my friends were disappointed in me and my mechanical ineptitude (in my dream).

Guitar 901 – Binding applied

January 19, 2009

As I wait for the walnut sides for the 12 string to arrive, I had a little free time to work on Zebrez.  I decided to use a simple black plastic binding for both back and top with no purfling.  As I want to try a sunburst finish for the top, I felt purfling would be distracting.

The plastic binding is applied with #16 Weld On acrylic cement.  Very easy to use compared to AR glue and wood bindings matched with purfling.


This shows the back binding after gluing and holding in place with binding tape.  Before doing the binding, I inserted a black plastic end graft piece.


First I cut out the channel for the graft, then carved out the wood to the depth of the graft piece, then glued and banged in.


This along with the binding install is only a few hours of work.


Guitar 805 – Bracing complete

January 19, 2009

All bracing is applied, and the top bracing has been shaped and final sanded.


The back bracing is on, but I will trim and final sand only just before attaching the back to the sides.


The sides are supposed to arrive tomorrow.

Guardian Cases: 4 received

January 19, 2009

Placed an order for 4 cases through a connection at Seattle Luthier’s Group.  Excellent price for the quality.  Got a Vintage (green plush, hygrometer) for the dreadnought and my 000 12 fret.


For the square neck resonator, a nice tweed with red interior.


And finally for Rachel’s OM a very inexpensive Deluxe/Standard.

Guitar 805 – forum provides answer

January 17, 2009

As mentioned, my dilemma and setbacks with the warped walnut back prompted a posting on seeking advice on how to work through or remove the warp.  A responder suggested I place the back pieces on a concrete floor with a plywood cover, then weighed down with about 50 lbs. and let sit for a week.  I did such, and it pretty much worked as advertised.  Although the warp did not entirely disappear, it reduced considerably, and I was able to resume with joining, backstrip reinforcement, and bracing without the disaster previously encountered.


This is a good example of what to do with that old Peavy amp that you’re not using anymore.  It’s heavy, and balances nicely on a 5 gal paint can on the plywood cover of the back plate (sticking out in the foreground).


I scraped off the leftover backstrip reinforcement scarf, and rejointed the back plates with my custom shooting block.


Decided this time to put the back plates face down in the joining jig to assure the backstrip and plates aligned flush down against the jig bars.


I’ve got to reexamine my threading pattern for this jig.  I think I need to add another “loop” at each bar to avoid driving the cross to the far end.

After curing sufficiently, I removed from jig and was pleased with the results.  Sanded smooth along the backstrip and installed the reinforcement strip.


The following shows the 15′ radius applied to the back braces, which are ready to install once the backstrip reinforcement has time to dry.


Guitar 805 – Top bracing

January 15, 2009

Received an order of BWB and was able to finish the rosette’s center ring with paua abalone.


This shows a bit of the superglue coating/flooding of the paua.

I got a bit ahead of myself and hadn’t put tools away in a while, so spent some time cleaning up.


Cut out the soundhole and laid down the x-brace, and bottom bout braces which I radiussed to 30′.  I also glued in the bridge plate.


The parlor is fretted and sitting awaiting convergence with the 12 string so I can lacquer finish both at the same time.  Whenever I have idle time with the 12 string, I’ll do some fine sanding on the body and neck, and work on getting the neck bolt holes and truss rod channel in the top bracing opened up a bit more.


Guitar 804 – Fretboard glued

January 11, 2009

The Koa Parlor is moments away from being ready for lacquer.  First added threaded nuts to the tenon, insereted the truss rod and applied glue.


Clamped wood is in place to keep the tenon from splitting while inserting the threaded nuts.


Glue on the neck, trying to avoid the truss rod.  Small pins were set in the neck, through the fretboard at the 4th and 11th fret slots to hold the fretboard in alignment when clamping down with the rubber band.


The rubber band does a good job of holding the fretboard tight against the neck and centering on the preshaped neck.



After the band was removed, side dots added, then sanded down to bring neck and fretboard in alignment.


Accidently superglued the neck to my ear, but I got it off.

Guitar 805 – Bending binding and purfling

January 11, 2009

Looking for things to do on the 12 string until the sides arrive, I test bend the crapped out walnut to see how it would do in the bender.  At 4.5mm, the sides cracked when I used the bender.  I half suspected this.  Also recognized that grain direction is important especially near the tight bend on the upper bout.  Will account for that when I postion the sides in the bender.  Also, if I get them down to 3mm, I should have not problems.

Also, trimmed the top to a skosh larger than final size.


After testing out the bender, decided I could go ahead and bend the curly maple and purfling.


This is the sandwich of binding and purfling in the bender prior to clamping down.


After cooling, I removed from the bender (nicely bent) and placed in the mold to hold the shape in anticipation of installation.

Guitar 805 – Warped back continues to plague

January 10, 2009

I made some advancement on working the rosette for the spruce top, but discovered I did not have enough BWB binding.  I installed the inner and outer ring, and will complete the center ring which will be BWB PAUA BWB when I receive the BWB I ordered today.


I measured the thickness of the wood on my Taylor 12 string, and at 3.4mm, I confirmed I had the thickness of my top and back around 3.5mm and proceeded with the rosette and the back reinforcement strip.

Here’s what the back looked like before adding the reinforcement strip.


I used my gobar platform to install the strip, and also forced down the warped sides into the radius dish to allow the glue to dry with the back in it’s eventual shape.


I was concerned about the cracking sounds that accompanied the clamping.  My concerns were confirmed when I released the back from the gobar and saw the backstrip had split.


So, now I am double trouble.  I don’t have another backstrip, I don’t have another back reinforcement strip, and the warped sides won’t like being braced without breaking the backstrip again (I suspect).  So, as part of my emergency order for BWB for the rosette, I added multiple backstrips, multiple reinforcement strips, and to be on the triple safe side, multiple curly maple binding strips and purfling (these objects will be bent in my bending machine, and God knows, I will probably break a few in the process of bending).

The beauty of my task list, mentioned in the previous entry, is that I have several task paths which I can take should one or more tasks go south on me, like the one with the back.

I worked a bit on shaping the neck, bringing the thickness of the headstock down to 15mm, drilling holes for the tuning machines and installing fret dots.

I have decided to install the tuning machines “down” as I like the balance better.


Here they are “up” (the tuning peg exits the shaft on the upper side).


“Down”.  I still have some right side peghead removal to get the dimensions balanced.  It’s a little fat on the right.

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