Day 17: Gluing bindings to the guitar body
DAY 17 – 15/3/2012 1pm-5:30pm.
Super productive day today. Bang, bang, bang. I routed a space for the bindings, hand bent the bindings, and glued them to the body!
Routing the sides of the guitar to embed bindings:
What are bindings? Bindings are the 10mm strip that goes around the edges of the guitar. In the cheap mass-produced world they are made of plastic. But mine are made from gidgee, one of the hardest woods there is (same as my fretboard).
I was told that gidgee will be extremely hard to bend. It’s a very dense wood, and thus very brittle. Last session I bent the gidgee bindings in the bending machine to get the main shape of the guitar. But today I must hand bend the tight cutaway part of the sides. There are four pieces all up. Two for the back, two for the front. Two will need to be hand bent to create the cutaway.
So much more work goes into building a guitar with a cutaway than I initially thought. I thought the only extra bit involved would be bending the sides of the guitar (along with redoing them cos they break) and that would be it. But there are a few structural changes to incorporate the cutaway, different techniques when creating a level guitar thickness, cutting out bracing, and now I need to bend the bindings to match the sides.
Why do you need bindings? Part of the reason is aesthetics. And I must say the dark gidgee strips on the edges will look stunning against the pale Bunya pine soundboard, and compliments the “blackheart” in the sassafras back and sides.
But bindings are also used for functional purposes: to “seal” the wood. The edges of wood, in this case all around the soundboard and the backboard of the guitar, are open and vulnerable to absorbing humidity from the atmosphere. This can cause the wood to swell, buckle, and change, effecting the way your guitar sounds. If you seal the edges with bindings, there will be less alteration during changes in the atmosphere. Even saying that, you will still notice a change in a guitar taking it from say QLD to Melbourne and may need to set up the action again.
The bindings are about 2mm thick (or 0.15 less than that), 10 mm wide, and you need two pieces to go around the perimeter of the guitar, for each side of the guitar.
I routed the depth and width of the bindings all around the edges of the guitar. Much care has to be taken during this part. Although you set the router up so that it can’t cut out more than the depth and width you want, you can make mistakes. The router can take off on it’s own accord, chewing out bits of wood you didn’t want to, and if you’re not aligned you can create unwanted gaps. My worst fear was eating into the soundboard……… To avoid this you must keep the router level with the soundboard, and have two hands on the machine all the time. It’s all about holding the router steady, having your feet in a good position, being comfortable, and stopping when you need to turn the guitar around to get the next part. Routing the edges around the back of the guitar are slightly harder, because the back has a slight curve. You want the router to be level with the slants of the guitar, not accurately vertical to the earth.
Chris routed the parts are the cutaway, as a demo. These parts are the hardest, as you lose a base to guide you.
Hand bending the bindings:
Last session I spent a good while practising bending pieces of gidgee on the heating iron. There’s a significant difference between bending sassafras and bending gidgee. I thought sassafras required patience, but gidgee took me to a new level of patience. I broke so many pieces. And it’s not just tears and splits, it snaps right through just like that.
I spent an hour bending one of the strips to match the shape of the cutaway.
It’s a VERY slow process of wetting the wood, placing it on the heating iron, applying weight to gently pull the gidgee down, but not too much pressure that you snap it. You’ve just gotta gently go with it. I had to keep going back and checking it against the body of the guitar, making the
sure bend was tight enough to fit the cutaway, wetting it, bending a little more, wetting it again, bending a little more.
There are two tight bends to create the cutaway. There’s lots of watching and even LISTENING required to make sure the timber hasn’t split somewhere. It’s mentally draining.
But to my surprise, the second strip took me all of 10 minutes to bend. Think I’m getting a feel for it. It was certainly a challenge. But it will look stunning, and I’m proud to report there are NO splits or fractures or tears!
Success! The bindings are now ready to be glued in place.
Gluing the bindings around the edges of the guitar:
Masking tape, masking tape, masking tape. And more masking tape.
There are four bindings to be done. For each part:
Temporarily tape bindings in place to measure what excess needs to be cut off at each end. Cut off the excess.
Prepare dozens and dozens of bits of masking tape stuck along the desk.
Apply glue to routed section.
Work quickly. Glue dries! And runs down the sides….. and seeps into the edges….
Start at the tail of the guitar, place the binding strip at the tail of the guitar and use several pieces of masking tape to hold in place firmly. Go along the edge of the guitar, taping VERY FIRMLY every 5-10cm. Do this part as quick as possible, but be sure to press the bindings in place well.
Go back and put tape along all the edges so you can’t see a single bit of binding. The technique involves leaning across the guitar and pulling the bindings in towards you (as hard as you can without the tape breaking), pulling them firmly into the guitar. If you can feel movement on the bindings, you haven’t taped them tightly enough. The cutaway section needs more tape. Sometimes 3, 4 layers of tape (think I applied even more than that in some parts of the cutaway section)
Now we play the waiting game.
It looks like a papier-mâché guitar.
It feels AMAZING to come to this point. The body is done. I can’t wait to take the tape off and check out the bindings on the guitar. Hopefully there are no gaps between the bindings and the body. If there are, they will need filling.
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