Question on laminated woods

Frank Wekenmann

Thank you Bob, that was the information I was looking for! Maybe you could answer a few more related questions:
Do you know any current builders that use laminated wood similar to the old Selmer style?
Did Selmer use Brazilian Rosewood or Indian Rosewood and would it even make a diference (apart from appearance)?
If I remember correctly, Maccaferri saw advantages in a laminated back. Unfortunately I don't remember which, apart from being more resistant to cracking. I would expect a guitar with a laminated back to have fewer overtones than one with a solid back. Is that correct?

Thank you very much,
Frank

djangoed

Very good post Bob !

Bob Holo

Frank W wrote:

Thank you Bob, that was the information I was looking for! Maybe you could answer a few more related questions:
Do you know any current builders that use laminated wood similar to the old Selmer style?
Did Selmer use Brazilian Rosewood or Indian Rosewood and would it even make a diference (apart from appearance)?
If I remember correctly, Maccaferri saw advantages in a laminated back. Unfortunately I don't remember which, apart from being more resistant to cracking. I would expect a guitar with a laminated back to have fewer overtones than one with a solid back. Is that correct?

Thank you very much,
Frank

(Q. current builders who use lam wood similar to Selmer)
I try not to talk shop with other builders or comment on their work... it just has a potential to get awkward. I've made no secret of the respect I have for Barault and Marin and the work they do in general but I've never talked about lamination with either. I could be wrong about this, but Leo Eimers and I are the only guys I've heard of who were daft enough to build exact replicas of the Selmer veneer presses and I think the originals are owned by F.Charle. I don't know if he loans them to Jean Barault but those two guys are friends. Ungainly things - about 45lbs each... am always tripping over them - I think they're almost as good at stubbing toes as they are at pressing veneer ;-) Those are the only facts I have and anything else would be complete speculation.

(Q.'s about veneer) Overtones & such... that's more about the relationship between the top and back and sound chamber than the materials used to make the back... it also has to do with the relationship between the top and the bridge, the string tension as a function of action, the length of the string scale, and to a certain degree the stiffness of the area under the fretboard both on and off the guitar's soundboard. Actually a lot of it has to do with string size too... the lower the mass of a vibrating object the more likely it is to produce harmonics within itself. So, 10s have more harmonics than 11s... 670 scale has more harmonic content than 640... and all of this is allowed to happen if there are no parasitic resonances due to the stringpath, the neck, the body cavity tuning or other things that can steal energy through dampening or vibrating in antiphase. The thickness and quality of the rosewood veneer is more important than whether it's Indian or Brazilian. Even with solid wood where differences among species is very important - amazing Indian is a better tonewood than mediocre Brazilian and a lot of the Brazilian still available is mediocre... (and unfortunately starting to get that way with Indian too...) but on a laminated back the difference isn't as great as you'd think. As for glue, the important part is the performance of the glue - its hardness - flexibility - glue-line thickness - failure modes etc... Fortunately I've found some very knowledgeable folks in antique restoration and have been learning a lot from them about finishes and adhesives. These people have the coolest jobs in the world... chatted with a guy the other day who was commissioned to restore the horse-drawn coach of ?? I forget... Adams or Franklin or Jefferson I think... Man oh man, if I'd have only known as a kid that jobs like that existed, I wouldn't have spent my 20's and 30's in tech engineering.

Frank Wekenmann

Bob,
once again a big thank you!!

murrayatuptown

Great post.

I have a friend who builds contrabasses with hide glue, and top of a 4/4 bass is a large area to glue and clamp...the one time I saw him do this I shut up and backed away until that step was done. He said he has enough working time, but can't spare any...no distractions. He doesn't use the traditional spool clamps so much anymore (friction clamps instead) for this reason.