Braces and Glue
The frames have been made for the four guitars. The tops have started to have their rosette channels routed. The next steps are to put in the rosettes for each top. Using the cnc to route those channels. Our goal is to get a body together. The braces need to be made and glued into the top and the back. We only have one go-box, which is used to apply the pressure needed to glue the braces in. There are eight pieces of wood that need to have braces glued in. Only one or two can be glued in during a day so this step is going to chew up a lot of time. An important part will be getting the process down to make a conveyor belt to get these all glued together in a timely manner. The steps happen in a few parts. The first one is to cut out the strips needed to make the braces. These are then bent over a form. Then the carbon fiber is cut out and glued into the bent braces. The braces must be cut into individual pieces then they are placed on a top or back and glued in using the go-box.
Wood bending has two main components: heat and water. These serve to loosen the ligands in the wood and makes them more pliable. When bending sides there is continuous heat that is added at the same time as the water. The water serves to distribute the heat and make sure that every part of the wood is hot. The water absorbs into the fibers and acts as a lubricate between the fibers allowing them to move more freely. The amount of water vs heat needed various.
The strips of wood are soaked in water. The water can be warm but it’s going to cool down over the time that it’s soaking. This step isn’t to add any heat to the wood it’s only to make the water absorb through the wood. It’s left in the sink for about thirty minutes. It can be left in longer but at a certain point the wood has absorbed all the water that it’s able to. The strips are thin enough that this doesn’t take a long time. After the thirty minutes are up the strips are tested by giving them a little bend. If it’s pliable then they can be taken out. If they are still tough, then time to soak for longer. The braces only need to bend enough to fit into our forms. The forms have nice gentle curves so it’s not asking the wood to bend far. It’s much less than bending the upper bout of the side, a notorious bend.
The wood is clamped into the jig and put in the oven.
Here’s Jay taking the braces out. It’s hot! Those clamps absorbed a lot of heat.
hey are left to cool down and hold into the form. It would be a problem to release them from the jig now and have them relax back to a flatter position.
The carbon fiber is rolled out and taped off in sections. This helps keep the end strands together when cutting it out.
A piece of wax paper is placed on top of the form, so the epoxy doesn’t glue the braces into the form.
The braces are cut out on the band saw and then placed on the top in a pleasing shape.
They are glued in using the go box. Glue is sticky and slick at the same time, so it takes some care to fit the braces in while pressing down on them.