Backstrips

[Darryl Young]

I jointed the Cuban Mahogany back this evening that will go on the 00 I'm building for my daughter. I'm ready to glue the halves together and started thinking about the centerline backstrip. Some folks glue the back halves on either side of the back strip (back strip runs all the way through the back) and others join the back then inlay the back strip.

So a couple of questions. What do you think are the pros and cons of these two options? The back strip measurements I've seen are as thick as the back of the guitar (or more). If you inlay the back strip, do most folks thin the backstrip down before inlaying? What depth is typically used? And finally, (just so I have a reference) which method do factorys like Martin typically use?

[Darryl Young]

Might as well throw out another question while I'm at it. I was looking at Burgeois (sp?) guitars on-line and a lot of his mahogany guitars don't have a backstrip. Is this typical? Also, it was difficult to determine if there was no backstrip whatsoever, or if there was a fine black line. Thoughts?

[Ben-Had]

Personal preference. I glue the strip between halves. Had to thickness one of seven.

[deadedith]

No strip is typical as well, especially for woods that the builder think are extra nice.

[Jim_H]

I've done it both ways.

The pro's for doing the full strip and then slotting, is that everything lines up perfectly. Con is that you have to spend time chiseling and cleaning up the slots. If you make them even a skoche too wide, you end up with a gap.

The pro's of doing the braces first and then adding back strips in segments is, you get perfect, tight, clean joints. The only downside I can think of the possibility of them not lining up perfectly, which is a cosmetic issue only.

I'm honestly not sure I have a preference. I would file this in the 'I'll cross that bridge when I get to it' file. =)

[hummingbird]

I've thought about this too. My conclusions are as follows. If you glue the backstrip between the two back plates you end up with two glue joints that have to be perfect instead of one, doubling the possibility of failure and weakening the joint somewhat. The joint as a whole will also be wider thus a slightly wider reinforcement strip is required on the other side. Inlaying the strip should not weaken the joint because the strip is laying across the joint helping to hold it together like the backstrip reinforcement strip on the inside. If you use a sharp router bit you should get a clean enough joint for the strip to fit snuggly. That's my opinion based solely on logic and no experience.

[tippie53]

gluing the back strip makes more sense than trying to rout in the strip. The joint will be supported by a cross grain support , and braces plus it is easier to make a joint than a route. Why add another process when you don't need to ? If you are not good at making a plate joint , then practice the hard stuff .
Joining a board is simple , you can use a plane , a shooting board , even a level surface. As long as the joint mates, by routing in a seam purfling you would then have to joint the board , then rout a cavity where you run the risk of oversizing it and tear out .

[kencierp]

I have always glued the back strips between the two halves - like John mentions, routing a channel is an intricate extra step. Personally I really like the appearance of a back plate that has interesting convergence of the grain in the center -- pretty difficult to improve on "mother nature."

[hummingbird]

I stand corrected.

[David L]

On the OO that I'm about to start building I had John join and thickness sand the back, he was kind enough to add a backstrip, however I had something different in mind for the back strip. I will route out the majority of the backstrip and inlay a strip of binding flat with purfling on both sides.
I like hummingbirds theory of a stronger joint integrity by routing the backstrip as opposed to glueing both sides, again, just my opinion, I have no experience, proof, or data to back this up. At this point I think we are splitting hairs and the difference is probably neglegable.

David L