Hollowbody guitars are often equipped with a floating bridge, which are prone to shifting while playing, travel, and during string changes. Floating bridges are usually only held in place by string tension, and as they’re very easy to knock out of place, it’s easy to throw your intonation all out of whack. The solution here is pretty simple: secure the floating bridge.
The crux of this issue is to solve wandering intonation problems. Intonation is the trickiest, and most mis-understood aspect of guitars (and all other musical instruments as well). It’s important to note that if your guitar isn’t properly set up, trying to set the intonation is pointless. So, before I even consider doing any intonation work, I fully set up the guitar. In this case, I leveled all the frets, setup, and intonated this Epiphone Joe Pass hollowbody before I started securing the floating bridge.
I’ve heard of people marking the top of the guitar around the bridge with a pencil or marker (or sometimes even a knife!) so they know where exactly it should be located, but this is ugly and unnecessary, and needlessly permanent. I simply mark off the bridge’s location with low-tack painter’s tape (which I de-tack further on my pants or shirt before sticking it to any guitar):
Now that I’ve got the exact location for the floating bridge marked out, I can loosen the strings and remove the bridge without fear of losing my place. At this point I’ve got the option to pursue a couple of ways of securing the bridge: I could permanently pin it, which, while invisible, is still invasive; or, I could tape it, which is strong, non-permanent, non-invasive, and cheap!
I use Scotch double sided film tape, which is strong stuff, but won’t mess up the finish. It’s also super thin, so the floating bridge lays flat on the body. I simply peel off a strip of tape for each foot of the bridge, stick it on, and then place the bridge back in it’s original position against the blue tape. Easy!
Once secured and strung up, it’s important to double check the action height and make sure the intonation is dead on (yet another reason why I write down all my measurements). When everything is perfect, I remove the blue painter’s tape and bask in the glory of yet another job well done. Huzzah!