Acoustic guitar reinforcing back strip or brace...

Replies to This Discussion

Permalink Reply by FloridaGull on February 21, 2012 at 6:00am

No theory - except perhaps individual manufacturer/designer desires?
I have no all-solid-wood guitars (except the Backpacker, I guess) - the only one with any kind of reinforcing strip on the back is my daughter's new Walden T550. The Walden is also the only one I have with a "stripe" down the back on the outside. The Walden and my 5th Avenue have a satin finish - all the rest are gloss (except the Backpacker).
I've wondered about this issue, too.

• ▶ Reply

Permalink Reply by Lyle Picciano on February 21, 2012 at 10:09pm

My understanding of the strip's purpose on a guitars with the purfling strip down the back is that the routing done to inlay the strip may weaken the strength of the wood at that point along the guitar's back (especially on guitars with a two piece back) so the feature adds reinforcement along that "weak" spot. What is confusing to me is that one person's statement seem to infer that any guitar with a two piece back must have this strip for strengthening because the glue (hide or any of the modern glues used today) used to join the halves is not going to be strong enough to hold it all together without the added reinforcing strip. This would mean that the guitars such as my Fullerton (solid, two piece back) and, for example, Martin's D-15M or DRS1 model acoustics (both solid, two piece backs) all should have the vertical reinforcement strip down the inside of the guitar's back or they would literally split apart at that point under string tension - and none of them have it. I've had the Fullerton for about 8 years now and it's fine, no evidence of any kind of crack or anything starting in that area at all. Martin (and I think I'm stating the obvious) would never build or sell an instrument with such a supposedly critical feature missing. That would be unthinkable, given their long history, experience and reputation as a major guitar company. So, it's a mystery as to why this is missing on those examples and on other guitars I've encountered. Are companies using some type of super-strong glue that precludes the use of the reinforcing strip (or brace)? Maybe they've developed some sort of special joint for two piece backs that, when glued together, are strong enough as is, no reinforcement needed? I can offer some practical guesses but I rather know the truth.

• ▶ Reply

Permalink Reply by FloridaGull on February 22, 2012 at 5:31am

I think we need the input of our luthiers - Jay Lichty? Where are you? ;-)

• ▶ Reply

Permalink Reply by Lyle Picciano on March 8, 2012 at 3:45pm

I emailed the Martin Guitar Co. about this issue a while ago and got a reply yesterday:

Hello Lyle,

The center strip on the back does reinforce the glue joint but it is not needed. We offer different styles and, in some cases, omit the back strip.

Darrin Trainer

C.F. Martin & Co., Inc

(888) 433-9177 X2205

So, I'm assuming that unless there is some sort of purfling stripe down the back of the guitar that requires routing along the glue joint, then the center strip is cosmetic, to give the guitar a more traditional look. I can rest easy now, knowing my guitars aren't going to "self-destruct" anytime in the foreseeable future!

• ▶ Reply

Permalink Reply by Jud Hair on March 24, 2012 at 7:48am

My solid wood Martin (w/ no purfling) and my solid wood Seagull (with purfling) both have the internal back strip.  My laminate Seagulls  (bookmatched backs/no purfling) do not have it.  I think it is just an extra reinforcement that adds a step of labor in manufacturing that you may or may not see used on less expensive guitars.  It has no impact on the sound of the guitar in my humble opinion.

• ▶ Reply