Tools and materials Required:
Japanese Pull Saws
Fine Dovetail Saw
Wood Chisels
Sandpaper 180, 120 Grit
Titebond III Glue
Wood Lining Blocks
Small Hand Built Miter Box
Acetone
Wet Cloth
Free-Floating Top Installation:
Whether it is a Classical Guitar top or an Acoustic Guitar top, the free-floating top, as I call it, can add some tonal qualities to you guitar – arguably so that is. In this article I will only address the installation of the free-floating acoustic guitar top. We will cover the Classical Guitar Top in another article, but much of the instruction used here can be applied to the classical guitar as well.
Why I Feel This Is Important:
Since the guitar top in the most important sound producing element of a guitar, it stands to reason that reducing stress related to this element will improve the overall sound of the instrument.
I feel that reducing stress throughout the instrument building process is very important and when I build my instruments, I ensure that everything fits together perfectly before gluing.
Not only does this give me a great sounding instrument, it improves the stability and the durability of the instrument.
By reducing overall stress to important joints, like the top plate and back plate attachment joints, side joints at the neck and tail blocks and all of the bracing, you are removing all but the string tension on the instrument – which is a necessary stress on the guitar.
Fit the top on the guitar much in the same manner that we discussed in our article Fitting the Acoustic Top. After everything is a perfect fit you should place the top plate face down into the inside mold. Now place the sides into the mold to fit onto the top.
Not Exactly a Free Floating Top
This is not the method we are after here.
Do a Final Fitting Check:
Check to see that the joint between the top and the sides is tight and all of the bracing is set perfectly in place. Also double check that the center-lines of both the top and the sides line up perfectly. If you need to do some last minute adjustment, you should do it now.
Before you start your gluing operation, clean the side where the lining block will be attached thoroughly with Acetone if your guitar is built from exotic wood or has heavy resins. Make sure no color comes off on the cloth for we are going to use Titebond to glue to top.
Place the sides bank into the inside form and put your Spreader jacks into place.
Assembling the Proper Materials:
Get your lining block materials ready, glue and some clean up tools, like a small chisel and a wet cloth. Also place a little pool of Titebond on some wax paper and have a small veneer spreading stick ready to coat each block.
Gluing the Blocks in Place:
Put your lining strip in the Miter Box and make your first cut. At most your block should be no longer that about 1/2″. You can choose to make shorter block around the sharp bends or shape them slightly with a sanding stick dowel or a belt sander.
Spread a small about of glue on the back and top of the block with the small veneer spreader and make sure all excess glue is cleaned from the block and set it into place. Move it back and forth slightly to get it to “set”. Move on to the next block. I like to have a small shim available to stick between the pieces to ensure that the spaces between the blocks are exact. You will find that the Titebond will set-up quite quickly, especially on the Spruce or Cedar tops.
For now just butt up to the top braces as you can decide on whether to place brace extensions on the top of the braces or not. Another common Acoustic Guitar method is to set one of the lining blocks on top of the brace scallop and glue it to the brace and the sides. Personally, I feel this looks a bit unprofessional. I prefer to see a fitted side brace – but that is from a classical guitar background I guess.
Tip: After you progress every 6 blocks or so – go back and check that the blocks are still seated properly and have not pulled away from the sides. If you have a stubborn block you may need to put slight pressure on it with a Wooden Cam Clamp and a caul (usually made from a small piece of lining that is reversed to hold the lining against the side).
Final Clean-Up:
You can do this as you go too, but just make sure you clean up any glue smears with the wet cloth that you can see. After the glue is dried, lightly sand the lining to make is smooth and even. You will be knocking off some of the edges by doing this and creating a much smoother appearance.
Tags: free floating top, gluing guitar tops, guitar building, how to glue a top, how to make a guitar
