Mold - Inside or outside?

[Bill Samson]

Just wondering if any of you makers can tell me their views on the relative merits and demerits of building a renaissance or baroque guitar, with or without vaulted back using a mold that fits inside the ribs, or a mold that the ribs fit inside.

[Peter Forrester]

The darker board (sheet of hardboard) provides a step between the surface of the neck and the neckblock/sides etc to which the belly will be glued.  In practice, it is 1+ mm thicker than the belly but this slight angle helps reduce the need for a thick fingerboard. So, yes!

I always glue backs on first, but perhaps because I made lutes before I made guitars!  Also because I always reinforce the joint with scraps of fabric.

[Michael. N.]

With Flat Backs I tend not to use moulds but utilise what Scot refers to as the Spanish method i.e. the little wooden blocks glued to the soundboard. End block and Neck (or Neck block) are glued directly to the soundboard. Sides are then glued to the end and Neck/Blocks with the Back going on last. It does require that the Sides are bent accurately and without twist - otherwise you can end up with a wibbly wobbly (great description) instrument.

I think I know why Peter suggests putting a curve to the Back bars. I do the same but it is very slight, much less than the amount of curve found on modern Classicals.

[Peter Forrester]

Agreed!

[Scot Tremblay]

I think it's a good idea to introduce a little arch to the backs of vihuelas, baroque guitars (the flat backed ones) as it adds a little strength...an arch is stronger than a flat surface. However, to keep things "looking authentic" I'd agree with Michael and keep it very slight'

 

The form-less method that I refered to as the "Spanish" method (not sure if there is another name) is an excellent way to build and I did all my insruments that way for many years. I just found that I occassionally would have to deal with a "wibbly wobbly" body and spend, what I considered, too much time getting things back in order. I still use this method for "one-offs" as it's by far the fasted and doesn't add anything to my ever growing pile of forms. 

 

Personally, I don't like the internal form as I like to see what is going on inside the instrument as I build, keep things clean of glue drips and so on. With the form-less or external mold this is easy.

 

I always put the backs on last as I build from the soundboard onwards. It's how I started with the form-less method and it just carried on to when I changed to forms. I certainly  can see the value of putting the backs on before the soundboard, for cleaning up the inside of glue runs (players of today like to look through the soundhole to see how diligent one is at keeping the inside of the instrument clean...moreso it seems than in the old days...some of the originals are pretty rough where one cannot easily see!) , adding the paper/parchment or cloth lining and such. But I guess, although I've tried it, I haven't made enough instruments that way to be comfortable with it. I have a proven sequence of doing things and going "backwards", as it were,  puts me out of my comfort zone. There are many paths to the same destination.