Fixing a Giannini classical

[Bizman62]

I don't know about fingerboards but Pete Seeger's banjo has a Lignum neck.  And there seems to be a fretboard of different wood on the neck so apparently some luthier grade glue sticks to it.

De-oiling and scraping for a better grip are most likely essential precautions.

 

[Prostheta]

Oh sure, plenty of people have used Lignum Vitae. Moreso years ago when supply was better and the whole "exotics" thing was less fraught with conscience-destroying....well, you know what I mean. I look at it pretty much the same way, that its specific properties are suiting the end use. For a fingerboard, hmm, difficult to say. I'd want to hint at fretless bass here, however oiliness is not the key but durability. Saddles and nuts would be perfect, and I believe that Carl Thompson has used LV in wooden saddles in a fully-wooden whale-tail bridge before. I don't fully imagine that the oiliness offers all that much to an instrument beyond what "traditional" choices do, which is already very little.

I fully support experimentation of course, but I'll add a bit of experience of super-oily woods to this to help form a better methodology. Stripping surface oils with a solvent only goes so far. The remaining oils/extractives in the piece will migrate across that gradient in no time, causing any delay in glueing to reduce success or encouraging failure over the longer term with "less suitable for purpose" glue types. Woods such as Cocobolo are about as oily as you can go before special measures are required, and even then it can be dicey with some pieces, however PVAc can still glue Cocobolo well if everything is done correctly. I'd recommend physical keying of the surface (80 grit sort of idea) and consider using a mechanical adhesive such as epoxy or urea formaldehyde. PVAc and other water-based glues have an extremely difficult time forming a strong wetted film between the mating substrates. With super oily woods (Teak being one I have used the most), wiping with acetone and using a resorcinol-formaldehyde glue has always been most successful, the end use being marine. An initial adhesion might not be indicative of long-term service.

[Professor Woozle]

Sound advice there, thanks. Fretless bass... there's something missing from the guitar harem at the moment, but I really need to get through all the other projects first!

[Professor Woozle]

Pulled out my lignum plank today for a look and had another possibly crazy idea - it's slightly over 25mm thick so maybe I could  make a one-piece neck, fingerboard and all. How to fit a truss rod would need a bit of thought. Anyway, enough on the lignum - next post will be back on the Giannini restoration...

[Prostheta]

Literally the only things I could drag from my own experiences with Lignum Vitae stop here. Everything I know is about origin, trade use and its working issues. From this point it's simply a case of getting the best hypothesis together and working knowledge to tip the scales in this direction. As a single-piece neck, yes, that truss rod will be the clincher. I'd like to think that a rear-mount compression rod would reduce the amount of glueing required, especially over a separate fingerboard. If the rod were waxed prior to insertion, then a fillet glued with epoxy (or other ridiculous adhesives as mentioned) into a freshly-degreased slot sounds the safest plan. Compression rods don't bear against the neck to the same degree as floating single/double acting rods, so there should be far less risk of the rod popping out a fillet. Equally, they are less prone to binding up should adhesive make its way onto the rod.

[Professor Woozle]

Quick update on this project, after glueing the cracked heel over the summer, finding an inexpensive set of Gotoh tuners on Ebay  and making a new nut and bridge out of African blackwood, I've finally got round to putting strings on. I've been bringing them up to full tension slowly, and so far, so good.

I did however notice when fitting the tuners that the mahogany of the neck seems to have faded in colour somewhat, and I'd suspected the same about the rosewood on the back and sides. I'm starting to think again about doing a full strip-down and refinish, but not right now!

[Prostheta]

It's the same with all things. A small fix here and there causes everything to get called into question. There's no reason not to do this though, however I would be tempted to suggest hitting the playability mark before investing more time and resources.

[Bizman62]

I'm with @Prostheta here, playability and structural integrity should come first. And I'm not so sure about the importance of fixing a faded finish. Deteriorating would be another thing.

[Professor Woozle]

That's what I was feeling about the old girl, make sure the repair is holding up and she's staying in tune before doing anything else. The finish is battered in places so I'll either need to do a load of small patch repairs or start afresh, but that's a decision for the future - right now, I'm too busy enjoying the special release cask strength Kilchoman Machir Bay...