Gluing The Back Center Strip
Source: Guitar Building Articles/The Guitar Back
The Back Center Reinforcement Strip
There are several schools of thought about in what order you glue the back braces and the back reinforcement strip.
Tools & Materials Required:
Fine Toothed Dovetail Saw
X Acto Saw
Go Board Tool
2-Part Instrument Epoxy Glue
Titebond II or III
1/2″ Sharp Chisel
Cardboard Protection Strips
Sharp Pencil or Marking Knife
Method One:
The first method is to glue the back reinforcement strip on the back first. Some Luther’s glue the strip on in one continuous length. I recommend that you cut the strip to the correct width and form its’ contour, whether that be a rounded or crown shape for the strip or just knock-off the edges.
After the glue has been cleaned-up and dry, carefully mark the back brace cut lines on the strip. Take a fine tooted dovetail saw or X Acto Saw and cut through the strip and stop just short of cutting through the strip. I like to put a thin piece of cardboard on either side of the strip to protect the back from the saw.
Now take a 1/4″ very sharp chisel and cut away the remainder of the strip under the brace and carefully peel up the glue residue as well.
Method Two:
Carefully mark the bracing, back and front block locations on the guitar back from your Guitar Building Plans. Cut and shape your center back reinforcement strip. Now cut the strip sections to fit between the braces, being very exacting in your cutting and checking.
Glue each strip section on the back, being careful to position it exactly on your layout lines. Preform a glue clean-up and remove from the jig. Now cut your back braces to size and fit them between the reinforcement strip so as to give you a snug fit. Glue the bracing when everything has been properly sized.
Method Three:
Carefully mark the bracing, back and front block locations on the guitar back from your Guitar Building Plans. Cut and shape your center back reinforcement strip.
Glue the back bracing into place and perform a glue clean-up. Cut your back reinforcement strips to length. Make sure that they fit snug between the braces so when they are glued they will not move around. Also make sure to form their profile prior to gluing them as this would be a much harder task once they are glued in-between the bracing.
Method Advantages:
For a long time I used Method One on my guitars. I liked the idea of having a back reinforcement strip that was “dead-on” straight. The problem I had with this method is the amount of time spent of cutting to receive the braces and the risk of damage to the back plate.
Once I started using the Go Board Tool and found that I could get the strips to stay in place with a bit of friction against the brace, I much prefer Method Three now. Just make sure to pre-form all of the strips prior to gluing in place and you can save vast amounts of time and effort post-forming this strip.
Although many Luther’s use Method Three, the risk of getting the strips even slightly misaligned is quite high and I don’t know about you, but if this strip is even slightly off it becomes very unsightly.
One Final Suggestion:
I would recommend to leave the two ends of the end strips slightly long. Mark the location of the butt block and neck/foot block just prior to final assembly of the back to the sides. Take a sharp dovetail saw or X Acto knife and cut them exactly to length so you get a nice tight fit.
Tags: acoustic guitar bracing, bracing the backplate, classical guitar bracing, Guitar Bracing, how to build a guitar, ultimate guitar building
