Tools & Materials:
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
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.
Carefully mark the bracing, back and front block locations on the guitar back from the Building Plans. Cut and shape the center back reinforcement strip. Next cut the strip sections to fit between the braces, being very exacting in cutting and checking.
Glue each strip section on the back, being careful to position it exactly on the layout lines. Preform a glue clean-up and remove from the jig. Cut the back braces to size and fit them between the reinforcement strip so as to give a snug fit. Glue the bracing when everything has been properly sized.
Carefully mark the bracing, back and front block locations on the back plate from the Building Plans. Cut and shape the center back reinforcement strip.
Glue the back bracing into place and perform a glue clean-up. Cut the back reinforcement strips to length. Trim so that they fit snugly between the braces so when glued they will not move around. Also make sure to form the strip profile prior to gluing them, as this would be a much harder task once the strips are glued in-between the bracing.
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. I found that with practice the channel for each brace can easily, and carefully cut and the ending result is a perfect looking back strip that is accurately aligned.
The problem I have always had with the second and third methods is the strips are very easy to dry slightly out of alignment and since these strips are highly visible through the sound hole, this was not acceptable.
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.