Harmonica maintenance: A must have tool

Last autumn my jazz quartet had a fantastic gig in Eskilstuna, a short drive from Stockholm. We've been playing together for over a decade, so our musical connection runs deep. I really enjoyed the evening.

During our soundcheck, my harmonicas were performing flawlessly. But as we headed backstage and sat down, I noticed a peculiar rasping sound coming from a specific note in the high octave when continued to play. Despite trying different attacks and volumes, the issue persisted.

Luckily, I had a secret weapon in my arsenal: metal shims. These unassuming tools are essential for the survival of my harmonicas. I carry them in 0.02 and 0.05-millimeter thicknesses, and each package is a whopping 5 meters long. You can find them in well sorted hardware stores. (as you can see on the picture below, I have twisted off the end - it is way better to cut it but I was in a hurry to make new ones.)

So, how do I use these metal shims? Let me show you:

• Cleaning between the reed and the slot: Gently insert the shim between the reed and slot to remove any dirt or debris that might be causing the rasping sound. Drag it carefully back and forth. For this use the thinner one, 0.02 mm. Move it really careful - they shims break if you drag to fast and hard.

• Plinking: Use the shim to gently tap the reeds and see so they are alive, return to original position and remove dirt. For this use the 0.05 mm.

Same on chromatic

• Supporting tuning: The shim can be used to support the reeds while tuning them. Use 0.05 mm

I also use it as a multi support when chamfering reeds. Or when tuning a big set of reeds, like raising a harmonica from 442 hz to 444 hz.

As you can see, metal shims are a versatile tool for any harmonica player. They're small, easy to carry, and can save the day when unexpected issues arise. I usually cut a four or five cm pieces and put in harmonica kit. I also always have a few in my wallet. I think I payed around 80 USD for each metal shim pack (5 m). I bought these almost 10 years ago. 5 m of metal shim will last a long time.

Here is a picture of a well used shim:

Have you ever encountered a similar problem with your harmonica? If so - I hope this helps.
And be shure to buy some metal shims 😀
Best,
Filip