Backpacker rescue

Graham has brought this Martin Backpacker to me to have its top repaired and a pickup installed…

…and it’s immediately obviously that the guitar has suffered a bit of damage and repairing the top isn’t really an option.

The size of the sound hole precludes any access to the underside of the stoved-in top and although the guitar plays ok, the only option is to make a new top.

I haven’t determined just how old the Backpacker is, but for such a tiny sound board, it sounds surprisingly good and I need to ensure that when it’s given a new top, it will still sound good.

Perhaps it’s just as well that StewMac, every guitar maker’s favourite supplier, has just started supplying Torrefied guitar tops- guitar tops that have been subjected to “Torrefaction”, a process that seems to genuinely pre-age spruce for an already aged look and sound and that’s just what I’m proposing to use for the little Martin to maintain it’s aged look and sound.

First- the removal of the existing top…

With the top removed, I can see exactly what’s happened to the top: at some stage, considerable pressure to the top has resulted in a split on the bass side and a broken away “tone bar” and a split in the side of the body on the treble side.

Even though the Backpacker is only small, a new top has to be made out of half of a dreadnought-sized top and of necessity, a new top will cost the same as a conventional guitar top.

However, I had bought in a couple of “torrified” guitar tops and I’m planning on building a small-bodied guitar for someone special and it seemed appropriate to glue up the top and with any luck, there will be sufficient for the Backpacker as well…

While the glue is drying, I’ll remove the bridge from the old top…

With the new top glued up, the top is thicknessed to exactly match the old top. If the thickness varies, then the playing action won’t be right but with the new top matching the old one, all will be good.

And now I can start to mark out the replacement top.

The scale length proves to be exactly 24 inches, not the usual Martin scale length…

With the centre line established, the bridge position is determined and marked on to the top..

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The sound hole is marked and then cut out.

…and using that as a reference, the bracing, bridge plate and sound hole reinforcement plates are made.

The bridge plate, however, has to be slightly enlarged because the Backpacker will be fitted with a K&K pickup which is mounted directly below the bridge saddle slot on the underside of the top.

The bracing and bridge plate are glued down.

When the glue’s dry, the exact position of the bridge is determined and the saddle position is transferred to the underside of the new top…

…by drilling at either end of the saddle slot.

A line is drawn that allows placement of the pickup elements in the right places…

The new top, with pickup installed, is ready to be glued on and I’m “dry fitting” to make sure that everything will line up.

Obviously, there will be cauls under the clamps when the glue has been applied…

The new top is still slightly over-size but I’ll trim it flush when the glue has been allowed to dry overnight.

When the top and sides are sanded, the bridge position is masked off…

I’ve been pondering on the  appropriate finish for the new top and it seems to me that the old finish is actually an oil finish, rather than the usual laquer and I’m going to use an excellent oil that I’ve found gives really great results…

After several coats of tung oil, the new top now looks just like the original…

…and where the sides were sanded- good as new.

The bridge tape is peeled off…

…and the bridge glued into position.

Saturday morning and although I don’t usually do guitar work at weekends, I wanted to put some strings on the Backpacker to complete the job. So after drilling the pin holes, I’ve strung the Backpacker with the recommended strings and tuned it up.

All good, the K&K pickup sounds really good, the action is spot on…but they’re still impossible to play…

Anyway- back to the crossword…