The liners run around the inside of the case and support the soundboard.
The liners and the walls of the case are supported by triangular blocks of wood called "knees". Finally diagonal buttresses are glued in place to give additional support to the bentside.
It is Titebond Liquid Hide Glue, which I use for two main reasons - it has an open time that is about twice as long as PVA glues which gives me more time to get things clamped and it is reversible. The reversibility isn't so much about being able to take the instrument apart again at some time in the future as it is about being able to recover from mistakes made during the construction process. http://www.titebond.com/product.aspx?id=9e9995b4-08eb-4fc6-8254-c47daa20f8ed
WOAH, the instruction manual directs using screws through the liners into the sides! That sounds like a recipe for disaster, especially for the bentside. So I came to your blog and see you are not using screws. There is no way I'll be using them - way too easy to punch through the sides - and I don't see that they're needed at all if one has enough clamps (I do). In fact, as I go through the manual I find all together too many screws for how I'd build even furniture, much less a fine musical instrument. I can only assume the design has the clamp-challenged customer in mind so uses screws instead.
Yes - the construction techniques are definitely aimed at making it possible to assemble the kit using as few tools as possible. I did use screws in most of the other places where they were suggested but had exactly the same reservations that you have about using them for the liners. I also succeeded in getting all of the outer case and lid moldings fitted without using any nails (not that there is anything wrong with using a few nails - I am just not very good at filling in nail holes so I prefer not to create them in the first place if at all possible)
Looking at the completed internal structure, I wonder why Ducornet designed so much bracing in his kit. The original Bocalari has two beams to keep the bottom flat and two knees on the belly rail. It has survived in playing order for over 3 centuries. Surely all those extra knees, struts and corner braces result in a significant acoustic departure from the instrument it's presumably based on.
I suspect that one of the main reasons is just to make the kit easier for amateurs to assemble.
That having been said, I haven't been able to find out anything about the original Boccalari other than the few remarks that appear in the construction manual.
The one on which this kit is supposedly based is not included in Denzil Wraight's catalog of Italian harpsichords although he does list 3 other instruments by Boccalari, and remarks of one of them (W545) that "The standard of workmanship is low".
So, perhaps adding a little extra bracing may not have been such a bad idea after all ...
got my little blurb on the construction from the Ferdinando Granziera introduction in the manual. Very interesting that the instrument in question is not in The List (Wraight's database). I thought all Italian instruments of any note (no pun intended) were there. Surely Denzel knows of this instrument and has asked to document it. I wonder why permission has not been granted. Mystery and intrigue...
What glue are you using? From the closeup of the knee it seems to be in the urethane family.
ReplyDeleteIt is Titebond Liquid Hide Glue, which I use for two main reasons - it has an open time that is about twice as long as PVA glues which gives me more time to get things clamped and it is reversible. The reversibility isn't so much about being able to take the instrument apart again at some time in the future as it is about being able to recover from mistakes made during the construction process. http://www.titebond.com/product.aspx?id=9e9995b4-08eb-4fc6-8254-c47daa20f8ed
DeleteWOAH, the instruction manual directs using screws through the liners into the sides! That sounds like a recipe for disaster, especially for the bentside. So I came to your blog and see you are not using screws. There is no way I'll be using them - way too easy to punch through the sides - and I don't see that they're needed at all if one has enough clamps (I do). In fact, as I go through the manual I find all together too many screws for how I'd build even furniture, much less a fine musical instrument. I can only assume the design has the clamp-challenged customer in mind so uses screws instead.
ReplyDeleteYes - the construction techniques are definitely aimed at making it possible to assemble the kit using as few tools as possible. I did use screws in most of the other places where they were suggested but had exactly the same reservations that you have about using them for the liners. I also succeeded in getting all of the outer case and lid moldings fitted without using any nails (not that there is anything wrong with using a few nails - I am just not very good at filling in nail holes so I prefer not to create them in the first place if at all possible)
DeleteLooking at the completed internal structure, I wonder why Ducornet designed so much bracing in his kit. The original Bocalari has two beams to keep the bottom flat and two knees on the belly rail. It has survived in playing order for over 3 centuries. Surely all those extra knees, struts and corner braces result in a significant acoustic departure from the instrument it's presumably based on.
ReplyDeleteI suspect that one of the main reasons is just to make the kit easier for amateurs to assemble.
DeleteThat having been said, I haven't been able to find out anything about the original Boccalari other than the few remarks that appear in the construction manual.
The one on which this kit is supposedly based is not included in Denzil Wraight's catalog of Italian harpsichords although he
does list 3 other instruments by Boccalari, and remarks of one of them (W545) that "The standard of workmanship is low".
So, perhaps adding a little extra bracing may not have been such a bad idea after all ...
got my little blurb on the construction from the Ferdinando Granziera introduction in the manual. Very interesting that the instrument in question is not in The List (Wraight's database). I thought all Italian instruments of any note (no pun intended) were there. Surely Denzel knows of this instrument and has asked to document it. I wonder why permission has not been granted. Mystery and intrigue...
Delete