Fixing Plywood Ply Separations
Source: Guitar Buzzes
Fixing Separated Plywood Plys:
Buzzing is a problem that has become more common as more guitars with plywood top and or backs and sides have infiltrated the market. Buzzes can occur if the ply of plywood have separated and are vibrating against each other.
Finding The Loose Ply:
More often than not, the loose ply will be the top ply or the one facing outward. You should be able to see a slight imperfection in the plate where the ply has let loose, because it bubbles outward. You can also detect loose plys by tapping over the entire surface of the plate and you will hear a distinctive difference in the area of the loose ply – believe me you won’t miss it.
This delamination is usually a result of a sharp blow or impact to the guitar. If the blow has been hard enough to put a actual hole in the plate, it is far easier and a better repair to replace the entire top or back plate of the guitar. ( I would replace it with a solid wood plate to improve the guitar sound if the guitar is worth it – in many cases it is not).
Tools and Materials Required:
Wood Cam Clamps
Titebond III Glue
Wax Paper
LED Work Light
Mechanics Inspection Mirror
20 gage Hypodermic Needle:
Begin The Repair:
First we need to put a opening or slit into the plywood top ply large enough to insert the hypodermic glue injection tool needle. I take a very sharp Xacto or Woodworkers Marking Knife and cut a slit the full length of the loose ply. Try to cut with the grain to minimize this scar. Now you can pry the loose ply up a bit and slip the gluing needle between the plys and inject a good about in the space. Do the same on the opposite side.
Ultimate Guitar Repair Tip: Note that if you have a ply separated that is deeper, you may need to resort to cutting a portion of the upper plys away to gain access to the cavity, or trill tiny holes large enough for the needle tool to be inserted through the holes.
Let the plys loose and massage with your finger. Now push down on the top ply while resisting with your other hand from inside the guitar. This will cause excess glue to squeeze out through the cut (or the holes).
Apply Wooden Cam Clamps To The Repair:
Apply a piece of waxed paper over the affected area and place a Wooden Cam Clamp through the sound hole to apply pressure to the affected area. If you are repairing a bubble in the back place you will need to place a wood prop inside the guitar, supporting both the top and the back and then position the Wooden Cam Clamp to apply pressure on the top and back plates, directly over the wooden prop and the loose ply. (refer to the diagram at the top of this article).
After the repair is dry, take a wet cloth and remove any dried glue and buff the affected area if required.
Tags: fixing guitar buzzes and rattles, fixing separated plywood plys, guitar buzz, guitar repair, how to fix guitar buzzing
