Welcome back to the wonderful world of restoration! This 1921 Martin 0-18 resides in the state of Minnesota and has seen its share of cold and dangerously dry weather throughout the years. As a result of age and the environment, it now bears a long list of needed repairs.
Last month we left off with the removal of the bridge, using a bridge/fingerboard iron warmed to a temperature of 250 degrees on a basic hot plate to achieve separation. With added help from the flexible Bridge Removal Knife, the ebony pyramid bridge came off cleanly with little to no tear out. After the bridge was removed, I could see that the underside gluing surface of the bridge had a slight twist to it. This slight warping was corrected by lightly coating the bottom gluing surface of the bridge with hot water and clamping the bridge to a flat slab of aluminum.
For this month’s operations, we will be using the following tools and supplies, all of which are available through Stewart-MacDonald ( stewmac.com):
- Spool clamps, large #0684
- Drop-fill toothpicks, #3110
- Glue brush #4167
- Epoxy glue, slow setting #5174
- Measuring spoons
- Cup and stir stick
- Hair dryer
At the owner’s request, I was to rebuild – not replace – the original damaged sides. There were multiple fractures on the bass and treble sides, both long and short with a few wide open, gaping cracks. To make matters more complicated, someone had previously tried doing some handy work on it, giving me more clean up to do. Would it be easier to replace the sides? Perhaps, but that would take away the challenge of making the repair borderline invisible. Let the adventure begin!
Before we could think about mixing glue, we first had to convince the separated ribs to line back up. This was not a one-man job, as the wood had a memory and did not want to follow my lead. Carson Lulic, the newest addition to Brown’s Guitar Factory, helped me with two extra hands. As I flexed the wood on the outside and through the soundhole from the inside to line up the seam, Carson put on the spool clamps with light to medium clamping pressure. This 1921 Martin’s sides are very thin and it wouldn’t take very much to overclamp, collapsing the sides and causing more damage.
Once the ribs were clamped to their original positions, we were ready to apply some light moisture to the damaged area. For this I used a sponge that fit nicely through the sound hole. The purpose of this is to rewarp the ribs to their original state so that when we remove the clamps it will make applying glue and the final clamping easier; more importantly, it will keep the excess pressure off the glue joint so that it isn’t destined to break apart at the seam again. A total of two moisture sessions were applied a day apart.
Gluing the Cracks
The glue of choice here was a two-part epoxy with slow setting properties. This provided us with some extra time for positioning and repositioning if the woods shifted during clamping. Epoxy will work as a filler and creates a very strong glue joint designed to never come apart. For this repair, I glued sections of 4” to 6” increments, as there were many small, uneven areas that needed to be addressed at the seam line of the crack. Once the glue was mixed, I used a glue brush and a drop-fill toothpick to apply it to the cracked area. When needed, the hair dryer provides heat perfect for thinning out the glue so that it can seep into the hard-toreach fractures.
Patience is a virtue with this project as the gluing can only be done in sections of 4” to 6” per day. With that said, there will be many days of crack repair ahead of me. Thank you for checking out Restoring an Original. I’ll see you next month.
John Brown, of Brown''s Guitar Factory, is the inventor of the Fretted/Less bass. He owns and operates a full guitar manufacturing and repair/restoration facility, which is staffed by a team of talented luthiers. He is also the designer of guitar making/repair tools and accessories that are used today by instrument builders throughout the world.