Last Update: 9/05/04

Online Apprentice-
Glue the Back On

In this lesson we will glue the back on.

Make sure you have read this lesson all the way through before beginning the lesson. A word of advice is to practice on scrap.

Now is the time to sign your work. It is also your last chance to do any final sanding and clean up of the inside.

Clamp the back to the body with spool clamps at the three brace locations.

Ok, here is the part that you will never find in any book. I came up with this method several years ago and have had much success with it. We used this same method in the Hauser course. In this course there is a slight variation.

Here are the specs that I am using for the action and saddle string height on this guitar. The action will be 3mm on the high E and 4mm on the bass string low E. The saddle string height that I want, which I measured off a Rodriguez guitar, is 12mm. I have to double the action of the first string E, 3mm x 2=6mm and subtract that from the desired saddle string height to find the height above the saddle location that my fingerbaord and frets will be aimed at. 12mm - 6mm= 6mm. Remember this number.You can change your numbers as needed for you desired action and saddle string height.

If you made the fingerboard/fret height block in the Hauser course you can use it for this one as well. If you are new to this course you need to make a dummy fretboard that is 0.281" thick (0.236"=6mm + .045"for the fret height= 0.281") and about 6"- 8" long. Clamp this dummy fretboard and a straight edge onto the neck.Locate the saddle position on the soundboard by measuring from the front edge of the nut marking on the neck. I like to add 2mm for compensation. At this saddle location your straight edge should read 6mm. The majority of the time you are going to be to high. What we do is we tilt the neck untill we get the right angle. For the Rodriguez guitar we are going to use a special shim to help us get the correct neck angle.

Here is the shim that will go between the upper back brace and the tip of the foot. The shim is a piece of scrap spruce and some extra veneer spacers. You will be amazed at the huge change in angle a .020" shim will make. By trial and error fit your shims until you get the correct neck angle. Err on the side of too high than too low.

This is what it will look like. Once you found the correct size shim remove it prior to gluing the back on and wrap it with a piece of clear packing tape. This way the glue will not stick to it when we attach the back.

Bingo! Got the 6mm height that I wanted.

***VERY IMPORTANT*** Do at least two or three dry runs of the following and each time check the neck angle!!!!

Apply glue to the lining, tail block and foot. Attach the back. Use spool clamps and start at the tail. Check the alignment and clamp the tail. Then check the alignment at the heel. Clamp at the six brace ends. Next install the neck angle shim. Fill in the remaining areas with the spool clamps. I use a Jogenson adjustable clamp for the heel block.

Use a caul made from scrap wood on the top and bottom to distribute the clamping pressure and to protect the back and top.

Wait over night and remove the clamps the next morning.

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