DIY Horn Speakers - Step 7: Gluing the Disks

There are several ways to glue a stack of disks.  Erik (from volvotreter) used a 2" rod to center the stack.  I didn't have a 2" rod, and I didn't want to run back out to the hardware store, so I ended up blue taping the exterior edges to center the slices and I drilled eight holes in each layer.  I used 1" screws and offset them between the screws of the previous layer.  They are way over-built, but I figured that this would be the easiest method to glue the stack once it got past the seventh layer and started to flare out, and I wouldn't have a 2" hole in the center of those larger pieces.  I also wouldn't have to even clamp the layers--the screws did a great job squeezing the slices together.  Glue would have certainly held the slices together, but it's always difficult to prevent drift when gluing, so I preferred to use screws.

It's very important that you don't glue the bottom layer by the throat because you will need to mount your compression horn to it and then mount that to layers 2-19 (depending on the thickness of your layers).  In layer 2, you will need to insert some t-nuts that you can insert bolts into from the outside of layer 1.  This way, you can mount the driver to layer 1 (the bolts bolt into the driver from the inside of layer 1), then mount layer 1 into the t-nuts from layer 2.  Be sure that the t-nuts are far enough from the compression driver so that you can tighten them (they should be fairly close to the edge).  The picture on the left comes from volvotreter.