Why are aluminum sheets used?

Hello everyone.
Last month, one of the members of my favorite idol group announced her graduation, and I’ve been feeling a bit preoccupied these days.

Ok now, I want to talk about the aluminum sheet that you can see attached to the pickguard and control panel when they are removed. Why is there a sheet of aluminum?
The point of it is that It reduces noise.

But how does it reduce noise?
The materials used in the pickguard are the resin which acts as an insulator, and the metal is a conductor.
In other words, if the metal does not collect the high frequencies that cause noise, the elements of noise in the cavity will be carried to the output line and come out together.

The metal control panels on Fender’s Telecasters and Jazz Basses are also made to reduce noise, which is the weak point of single-coil pickups.

Therefore, the entire panel acts as a grounding, which saves wires by eliminating the need for wiring material because the pots or jacks don’t need to be wired using wiring materials for a grounding.
In addition, by not wiring to the grounding, the technician’s skill level doesn’t need to be high, and the work time can also be shortened.
In other words, using metal control panels is an innovative design that can increase production efficiency with part-time personnel with no manufacturing experience.

Many Japanese vintage guitars that have become popular in recent years also have aluminum sheets on the pickguard to leave out the wiring, and Gibson has done the same thing by placing an aluminum plate inside the control cavity.

However, despite the seemingly good points of aluminum sheets, of course there are drawbacks.
For example, if the ground wiring is left out as mentioned earlier, this can cause unstable continuity and noise if the pots become loose.
For this reason, although it varies from guitar maker to guitar maker, I think that many guitars with aluminum sheets on the pickguard or metal plates such as Telecaster also have the pots wired to ground.

Also, it is often said that there is a high drop-off, or a loss of sparkle in the high frequencies.
To be honest, I have never been concerned about it, but many people seem to care about it.
I can’t say for sure, since I have not measured the exact values myself, but theoretically, the high frequencies in the cavity are discarded, so there is no doubt that the sound is affected in some way.
However, the effects may vary in degree and there are some people who prefer that sort of sound, so I think it would be better to try it for now and if it is good, leave it as it is, and if not, remove it.
The cost of an aluminum sheet is not that expensive.

Now that I have talked about aluminum sheets, here are some points to keep in mind when using them.
First, the most important thing to do is to ground it.
If it is on the pickguard, it will be in contact with the pots and it should be fine, but the problem is when it is mounted on the control panel on the back of the body.
Like Les Paul, some guitars have the electrical parts directly attached to the body and the back of the guitar is closed with a plastic panel. In this case, the aluminum sheet is not in contact with the parts and must be grounded in some way or else in order to eliminate the noise.
The most common method used in products is to apply conductive paint inside the cavity and use copper or aluminum tape to make contact with the panel.
This method is the most standard, but...
“What is conductive paint?” For those who have no idea what conductive paint is, I will explain more about it and mention some precautions on it in the next issue.

Also, something that is equally important to do before mounting is to check the conductivity!

Why? You would think that conduction would be okay, but surprisingly, they are not.
Aluminum sheets are sometimes coated with a solvent to prevent corrosion, and this may be the reason why the conduction cannot be obtained.
Most of them will not be a problem, but in such cases, wiping with paint thinner, parts cleaners, or nail polish remover will remove the solvent and allow conduction to be restored.

Another note of caution is to use only one single aluminum sheet whenever possible.
I have seen some people use aluminum tape (about the width of packing tape) sold at hardware stores as a substitute to save money, but commercial aluminum tape is often coated with the corrosion-preventive solvent which I mentioned earlier.
The glue used in the tape is an insulator, so if the tape is adhered on top of each other, some aluminum tapes cannot obtain the conductions.

I tested the conductivity with two layers of random aluminum tape that I found in the office but unfortunately I couldn’t get it to work.
If this happens, working hard will be a waste of time and money, so I personally recommend using a single piece of aluminum sheet sold for musical instruments.

Finally, I would like to introduce some aluminum sheets sold at Sound House.

Montreux / Aluminum Shielding Tape [8641]

This is the most standard aluminum sheet, which can be cut to any size and used for pickguards and cavity panels.

Montreux / Montreux SC Aluminum Shield Plate [9173]

Fender / American Vintage 62 Stratocaster Pickguard Shield Aluminum

These products are aluminum plates that are thicker than aluminum sheets and can be inserted between the pickguard and the body.
It is a very convenient way to reduce noise just by inserting it between the pickguard and the body, but there are restrictions on the number and positioning of the holes in the pickguard, so please check the compatibility carefully when purchasing.

LOGOS / Non-stick Yakisoba Sheet

The last one is a non-stick, ultra-thick aluminum sheet from LOGOS.
Although this sheet is not for musical instruments, it can be used as a substitute for a griddle just by laying it on a grill, and because of its thickness, it can also be used as a pot if you can shape it into one and cook with it!
This product is recommended for those who like camping and BBQ.

How was it?
This time, I gave an explanation on the aluminum sheet attached to the pickguard.
As for noise reduction, I personally feel that it is quite effective, so I think it would be a good idea to try it once if you have a noise problem.
Well, because they are so effective, many guitar makers use them, and each maker uses different methods to install them.
I hope that those who read this blog will be interested not only in the performance aspect of guitars, but also in the structural aspect.
Thank you for reading to the end.
Come again soon to the Sound House Staff Blog.