To shim or not to shim

kungfumonk007

What are everyone's opinions. I was always told to shim, but Christiaan told me not to shim the other day. Advantages/disadvantages. Maybe the legendary Bobolo could chime in?

nomadgtr

Timely question Aaron! I've been mulling this over the past couple of days as well. The recent bout of low humidity has left me with a little buzz and it isn't the good kind if you know what I mean.

richter4208

i called gypsyguitars down in LA and he told me he custom does bridges and even matches color of mustaches. Maybe instead of shimming get a bridge just a touch higher so you can swap them out due to weather shifts etc??

David Lawrence

What was his reasoning for not shimming? Just poor resonance?

kungfumonk007

Bridge contact.

anthon_74

I shimmed my guitar once when it was sounding not so good, and the suddenly is sounded amazing, like a new guitar. I say try it out and see what happens. The problem with not shimming and getting it fixed by a tech is that these guitars are very touchy and shifty. So you can spend a bunch of money, only to have it go right back out a couple months later due to weather factors. The shims are cheep and you can add and remove as needed.

Anthony

Craig Bumgarner

Shim it! Up to a point at least. Well fit shims do not harm the fit of the bridge to the top or the tone. Shims offer more versitility than alternate bridges and are easy to install.

Material is not crucial, any reasonably hard material will do, hard wood, hard plastic.

Commercially sliced wood veneers are typically .5mm. You can glue two together to make 1.0mm, just be sure to clamp them while the glue sets. You can buy small packs of veneer on Amazon including some maple veneers dyed black.

Old credit cards or gift cards make good shims, typically .7mm. Plastic cards are reasonably hard so they transmit vibrations well enough.

Of course Django shimmed his bridge, but I can't say paper train tickets and match book covers are the best material, but worked for the master.

Again, fit is more important than material. Use shim stock that is of even thickness. Shims should be the same thickness on both sides of the bridge for a good fit. To check the fit, hold the guitar up to the light, sight the plane of the top and you should see no light through the bridge feet. If you do and you are using good shim stock, the bridge may not have been well fit to start with. Using thicker shims on one side than the other can work in small doses, but be careful of going too far. It this is needed, better to glue shims to the bridge feet and reshape.

I prefer to glue up shims to the thickness needed rather than loose stack them. More than two loose shims starts to affect the fit and starts to feel soggy under foot :-) Another option if the bridge is always low is to glue shims to the bridge feet.

Jeff Coult

I have experimented with shims with good results for small changes, less than 1mm. I was also advised by my luthier to keep a humidifier in the sound hole anytime the guitar is in the case, as a drop in humidity can sag the soundboard, drop the action and affect tone. I've shimmed then played a DuPont MDC50 and Shelly Park Montmarte.

Jazzaferri

I have never had to shim my Dunn or my DuPont. RH here is fairly consistent though both go through a bit of an adjustment period every spring and fall. Dunn can get a bit buzzy for a week or two then it settles in and all is good again. Action may change slightly but the sound stays the same.

Dupont action seems to be more noticeable but as its a short scale D Hole and I am playing rhythm on it I don't much notice it.

wim

Shims are for when your guitar moves! I wish I could shim like my sister kate ..

If you have the same height of shims on there for the whole year (e.g. you don't travel or your climate doesn't change or the guitars top is very thick), then you should just have the correct height bridge built and ditch the shims. There is a small but noticeable sound improvement.

If your guitar moves like crazy and the action is changing, even though the neck is straight, then by all means use shims to manage that.

It's a path to insanity trying to set the action on a moving guitar just by using the truss rod. Because that part is only one part of the equation.

What was Christiaan's proposed alternative to not shimming? It's a necessary evil for a moving guitar (and they all move to some extent), unless you want to carry a bag of bridges around or just play a badly setup guitar for half the year ...

Jazzaferri

The humidity in Holland is usually pretty much the same year round as it is here. If you live in DC however or other parts where its warm and muggy in summer and really dry cold in winter, humidity control and shimming are necessary evils.