Gluing on a bridge
I’ve just glued the bridge onto the parlour guitar. This time, I didn’t video the process because I find this very final stage the most nerve-wracking of them all. You’re working with a variety of sharp tools on the freshly finished soundboard and need to concentrate 100%; months of hard work could be written off in the blink of an eye!
However, I know that there is a lot of interest, out there, in this particular stage, so I thought that I’d explain the process for you.
The first step is to cover the general area, where the bridge will go, with masking tape. I use a low tack tape designed for delicate surfaces; it is possible, if using very strong tape, to pull the finish (particularly water-based lacquers) clean off of the guitar! Don’t ask me how I know!
Next, some very careful marking out; I use a soft 7B pencil so that you don’t have to press too hard to make a mark. As I was marking out I counted that I needed 4 different types of ruler to measure with!
Once I’ve checked 27 times that the bridge is in the correct position, I scribe the outline with a scalpel (brand new blade!). You have to cut through the tape and lightly score the surface of the finish; once through the tape you can feel (under the blade) the different densities of winter and summer growth on the soundboard. A small piece of double sided tape locates the bridge nicely.
Remove the tape from the area under the bridge and scrape the finish away; you’ve got to get back down to the bare wood so that the glue bonds.
I use a chisel for this; I run a burnisher over the edge to form a burr so the chisel can then be used as a scraper.
With the surface of the soundboard clear of finish, the bridge can be glued on. I find that the tape is enough to stop the bridge sliding around and once the glue has grabbed, I gently remove the tape; this helps to remove excess glue that may have oozed out.