Preparing for Minimum Noise (1) - Sealing the Cavities

One of the discussion points I came across was regarding proper earthing and eliminating sources of electrical noise. The prevailing opinion was that there is merit in electrically shielding the electronics from any sources of spurious noise. The two main options to achieve this are to finish the main control cavity with either copper impregnated paint or copper foil tape. To be really thorough, you can do the same for the pickup cavities. The paint may be effective, but again, the opinions I came across thought the paint to be somewhat unreliable. I have chosen to apply copper foil tape. If I have enough left over, then I will also attempt to line the pickup cavities.

The first step in the copper application process is to prepare the cavity for the best adhesion of the tape by sanding away the obvious lumps, bumps and machining marks. So this I did, using 400-grit sandpaper. I used this reasonably fine grade paper so I did not to remove too much material too quickly.

Sanding sealer came next because I thought it might be worthwhile. Sanding sealer prepares the raw timber for other clear liquid finishes, such as stains or varnishes. It is supposed to fill the wood grain to produce a smooth, even surface. The rationale was, that by filling the wood grain, it would provide the maximum possible surface area for the foil tape to stick to. I didn't want the sealer to influence the proposed tung oil finish for the rest of the wood, so I masked around all of the cavities before painting on the sealer.


The pictures show the cavities after I had painted on the sealer. There are a couple of points to note here, that may be of interest. The first being the colour change in the wood. Compare the cavities to the neck pocket or the main body, which weren't painted. This may be relevant if you are thinking of using a clear finish over sealer for your own project, but more discussion on this in a later post.

Also, from the lower photo, the relationship of the control holes to the cavity is clear. You can see how much space has been allowed for the body of the controls, as well as the small countersink next the hole for the orientation tab on the controls.

 Another modification I haven't mentioned before is the tiny bit of extra routing made for the switch. This allows the switch to be placed where I wanted it, but also for either a back-forward or up-down action. I'll make that decision after the wiring is finished, much later.