Martin Reynolds


Making a

For those of us who live in cold northern climates, keeping your guitar from going grossly out of adjustment or even cracking is a real problem. I make and sell a lot of these every winter. They are easy to make and are the best humidifiers you will find anywhere.

For parts you will need:

  1. Plastic soapbox, the type you would use while traveling.
  2. 3M Ocelo sponge or any good quality anti-bacterial sponge.

Here's the type of box I use.

I use a drill press and a locating jig, you can use a hand drill.

I drill two holes using a 1 1/8" spade bit but if your using a hand drill you should use a hole or lock set bit. Brace the box against something while drilling, this will give you better control.

The locating jig acts as a brace to keep the box stable. If your using a hand drill go slow and you will get a cleaner cut.

Even my nice drilling set-up leaves the holes a bit ragged.

This is a utility knife blade with a bit of tape for a handle.

Using it as a scraper you can clean off the rough edges leaving them nice and smooth.

Since I make several dozen of these at a time I use my band saw and cut the sponges two or three at a time. Scissors will work just fine if you cut one sponge at a time.

Cut the sponge to the outside diameter of the box. When fresh from the package the sponges are damp, if dry, wet and wring the sponge before measuring and cutting. This will insure a proper fit, too tight or too loose may cause leakage.

When properly fitted the sponge will have no lumps or wrinkles and will stay in the bottom of the box.

To fill, open the box and soak the sponge completely. Press both thumbs firmly into the sponge and invert while it drains.

In the winter you should have at least one of these per guitar case. In northern climates you may want two humidiboxes per case.

I have been developing these humidifiers for about six years, Yes they are just a box and a sponge but there is quite a bit of physics in the way they work. A few points to keep in mind when making these.

  1. Large holes work much better than small holes. Two 1" holes will do the job, One thousand holes with an icepick will not work well.
  2. Notice that the sponge does not fill the whole box, only the bottom half. You must leave an air space between the surface of the sponge and the lid.
  3. The box I choose is made of fairly soft plastic, not likely to cause damage if the case gets some rough handling.

Periodically the sponge should be cleaned by placing the wet sponge in the microwave for one minute This will kill bacteria and mildew.



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