To shim or not to shim

rgrice

Didn't Django and others often shim with picks or whatever was around? I know there are probably technical and scientific truths at play, but I doubt the originals gave a crap!

Craig Bumgarner

Picture of Django with train ticket shims..... Sort of a cheap shot actually, he's using a mag pickup, so the acoustic qualities of the bridge are not all that critical. No doubt will fit hard wood shims would have been better, but either way, did not seem to slow him down. :-)

wim

Train ticket? Somewhere I heard that the shim under 503 was a weight card ... like a machine where you put in coins and it gives you a little printout of your weight

Bob Holo

Yep, absolutely, you can shim with anything, but if you shim with a soft material, it will eat treble, and if you shim the bridge a lot - or unevenly, it can load the soundboard oddly, or at worst, crack the soundboard. Those cracks at the inside and outside ends of bridge feet are common on vintage instruments and ill-fitting and/or poorly-shimmed bridges that don't distribute the string pressure evenly across the bridge feet are how they happen. It might not crack at first, but if the guitar gets dry and is already stressed and puckering/telegraphing over braces and etc., that sharp bridge end digging in to the soundboard will create a place where the soundboard can relieve its stress through opening a crack.

But shimming with soft material is not unheard of, and if you do a reasonably good job and you don't change the bridge's fit or significantly reduce the bridge footprint, it won't damage the guitar. In fact, some people like a softer, mellower sound. Playing with the backward Gator pick is one way to get a mellower tone because you get less pick noise. Shimming with poplar/basswood is another way because you attenuate harmonics and treble. Poplar was very popular (oh, that was a bad bad pun) as a shim material because cheese wheels were packed in poplar and other soft whitewood veneers and there was a whole lot-o-cheese in France back in the day. Availability and Necessity are the parents of invention ;-)

But sure, do whatever floats your boat.

Rock on

\m/ \m/

klaatu

I bow to Craig's knowledge and would add that Rodrigo Shopis advised me to shim if I needed to due to the dry winters here in Nova Scotia, so there's another master builder weighing in.

Although I've never needed a shim on Rodrigo's guitars. I humidify, and they have all been very stable.

nomadgtr

I added a shim on just the low end this past week and it's really made a significant difference and in a good way. My guitar doesn't necessarily get a steady humidity level in the summer months. I live at 7200 ft here in Colorado and we regulate temperature with windows vs. air conditioning around here for the most part. The fresh air is great but not the best for acoustic instruments. Keeping the guitar in the basement helps steady the humidity somewhat though.

pdg

I have come up with an adjustable height bridge for GJ guitars. I'm fine tuning it for tone, but the volume is there completely -- even louder than with regular bridges. I use aircraft grade aluminum posts and thumbwheels, which weigh next to nothing, so the bridge doesn't end up weghing more than a traditional GJ bridge. I'll mever look back . . . .

Bones

Hey pdg, watch for galling of the aluminum threads if u adjust the height under string tension???

Jazzaferri

A little teflon lube in the threads will cure that one. Good thinking @Bones. An oz. of protection Etc.

Steveareno

I use cut down Popsicle or ice cream sticks for shims and they work great. Just the right thickness. Raised my action perfect. No buzzing and easier string bending,. I'm told they're made of maple (some kind of solid wood, anyway). Easy to trim to size with an Xacfo knife, or heavy scissors. I colored them brown and are hardly noticeable. You can pick them up in packs for a couple of $ at a drug store, or supermarket. I say definitely shim.

Swang on,