Mentioned on the URB Thread...
This was a tricky repair that I just sent out the other day. An all solid wood Eastman bass, with a long split from the tailblock up. Part of it was pushed in, part splintered out and badly misaligned. The 'right' way to fix this would arguably involve some disassembly... top off, to gain access so one could realign the wood ribs and properly cleat the crack. Then put the top back on. If it were a laminate bass, I'd have just heated up the iron and got the seam knives out. But a laminate bass doesn't split like this to start with... so, there's that. Anyway, in addition to being a ridiculously big job, it was just too dangerous. I started thinking about another way. And though I arrived at the conclusion independently, that I needed some way to pull the cracks together flush, then glue and clamp them, I still didn't know how to execute the task.
My friend and mentor Ward Elliott rescued me again, with this guitar string winch. He had a few of these made up in various sizes and shapes, with a heavy plexiglass frame, with a salvaged guitar tuning machine mounted through it. See, you drill a tiny hole through the affected area of the instrument. Slip a guitar string through it (I used a G) an then fish the end of it up through the bass'es f-hole. I used a magnetic rod for this. Then the pre-made, and pre-glued maple cleat slides down the string, backed with a brass bushing. You pull a knot in the guitar string to seat against that bushing, and pull the slack out through the tiny hole. Slide the guitar tuner 'winch' in place and tighten up the string until the misaligned wood is flush. You'll soon start seeing some glue squeeze-out. I work a little more glue into the surrounding cracks at this point, then put a cam clamp from top to back. The trickiest part of this entire operation is making sure the cleats are oriented the way you want them. It took some doing. And patience. I used luthier's grade fish glue for this. It's very high tack, but slow to set. (equals time to work)
It was a somewhat slow process, working from the worst spot, the most misaligned part until eventually all of the crack was massaged back together and cleated. At a couple points I found it helpful to put an extra clamp 'downstream' of where I was working and place a scissor-jack and cork-lined caul to help hold things in place for some stages. Total time on this, about 6 hours. But that is waaaaay less than if I'd had to take it apart. The repair is just as strong too. I'd feel good about this one even if it was my bass.
Also feels good to learn new tricks. Hope the pictures illustrate better than I explained it.
