Torres, Santos back glueing method

Construction and repair of Classical Guitar and related instruments
anders

Torres, Santos back glueing method

Post by anders » Tue Apr 18, 2017 3:38 pm

Does anybody know a good procedure to fit the back in the way that Torres and Santos sometimes did, that is attaching the back braces to the sides first and then glueing the back to the sides and bracing. Seems like a good way to get a nicely arched back but I don;t know how they would get it done before the hide glue skins, my only theory is they reactivate the glue later with something like a clothes iron.

Anybody on the forum done it this way?

Cheers,
Anders

Alan Carruth
Luthier
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Re: Torres, Santos back glueing method

Post by Alan Carruth » Wed Apr 19, 2017 3:29 am

I was told that Torres used to put some alcohol on the back with a paintbrush where the braces were, and light it on fire. Apparently he used a little tooo much soometimes and scorched the backs a bit, leaving dark stipes across them.

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Michael.N.
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Re: Torres, Santos back glueing method

Post by Michael.N. » Wed Apr 19, 2017 6:59 am

I've done it without reactivating the glue but I pre warmed the parts. I also added a bit of salt to extend the open time and the clamping set up had to be very efficient. Having said that I normally warm through with the clothes iron, less stressful. The difficulty with the method is getting a good fit over the bars.
Historicalguitars.

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heikkinurkkala
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Re: Torres, Santos back glueing method

Post by heikkinurkkala » Wed Apr 19, 2017 11:36 am

I am currently building my first guitar a'la Jose Romanillos book "Making a Spanish Guitar"
I contemplated to use hot hide glue when gluing back to sides but decided not to use it because my cold workshop and too high strength hideglue(280).
I used fishglue instead and it worked well...
I made preradiused sanding cauls whereby used to shape back braces, spanish heel and side-to-back joint. When braces were glued to sides I made temporary support blocks for braces so they dont sag under the back, and which I removed after back was cured. I used also "papal cross" device from the book which helped to spread clamping forces during back gluing. I used rope as a clamp.
I could later take a photo of "papal cross"-device what I made.

If you are interested my build log is on instagram search for "heikinnurkka"

Best regards
Heikki

RedCliff
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Re: Torres, Santos back glueing method

Post by RedCliff » Thu Apr 20, 2017 6:18 pm

Here is a great build video - ok it is a ukulele from a long time ago - but it shows how to do the back braces first and then the back - makes it look simple really!

http://www.ukulele.org/?Videos
Giles Ratcliffe
Sheffield
England

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Steve Ganz
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Location: Blaine, WA, USA

Re: Torres, Santos back glueing method

Post by Steve Ganz » Thu Apr 20, 2017 7:33 pm

heikkinurkkala wrote:I am currently building my first guitar a'la Jose Romanillos book "Making a Spanish Guitar"
I contemplated to use hot hide glue when gluing back to sides but decided not to use it because my cold workshop and too high strength hideglue(280).
I used fishglue instead and it worked well...
I made preradiused sanding cauls whereby used to shape back braces, spanish heel and side-to-back joint. When braces were glued to sides I made temporary support blocks for braces so they dont sag under the back, and which I removed after back was cured. I used also "papal cross" device from the book which helped to spread clamping forces during back gluing. I used rope as a clamp.
I could later take a photo of "papal cross"-device what I made.

If you are interested my build log is on instagram search for "heikinnurkka"

Best regards
Heikki
Heikki, your build is looking good. I don't have the book, but I went to the Romanillos course in Spain a while ago. His "papal cross" was so thick and stiff that I was scared to use it and we thinned it out for use on my guitar. I wonder what the specifications in the book say about that. Would you mind sharing?
Steve

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