DIY | Fill the f-holes on hollow-body guitars

If you ever amplified the signal of your hollow-body instrument you surely have met Mister Feedback. So you lower your volume so much the audience only hear the drummer while you were eager to show off some licks stolen from Robben Ford.

Some people put tape over the f-holes, others like BB King stuff them with paper…
While looking for a better solution to remove feedback, I came across this site which makes EVA foam plugs. Rather than breaking the bank I decided to put my shoulder to the wheel.
Of course if you already robbed the bank, pay a pro to do this. If you’re poor, read on.

The idea is to fill the hole with a material that lets the air flow as little as possible and which is also able to conform to the shape of the f-holes. Well, having something reliable and not too ugly.

EQUIPMENT :

  • EVA foam sheet. They can be found on children’s toys stores.
    I payed around 0,70€ for each sheet (dim : 20x30cm / thickness : 2mm).
  • Neoprene glue.
  • Double-sided tape. cutter, scissors…

HOW TO :

Tape a paper sheet around the f-hole to make sure it doesn’t move. If your afraid about the varnish of your guitar use painter’s tape instead or a slave to hold the sheet. Scribble above the hole to make the lines of the hole appear on the sheet. Here’s the exemple on my Hagström Viking :

Boucher les f-Holes d'une guitare

Then carefully cut the f-hole shape drawn in the paper and fix it with the doubled-sided tape on an EVA foam sheet.
As I only found 2mm thick EVA foam sheets, I previously glued 2 sheets together to be sure to fill the whole thickness of the f-hole and more :

Boucher les f-Holes d'une guitare

Next, cut the shape around the paper with a cutter or scissors. Once the foam is cut, test on your instrument.
I had to make some adjustments after the cut, the shape was too wide and didn’t came into the hole.
The foam has to be just a little compressed into it. Cut and test again several times. This is the most time consuming part.

For a nice finish & complete the airtightness, fix the paper shape on a piece of thin foam (2mm was ok for me) and cut between 1 and 2mm around the paper. This will be the visible and embossed part on the guitar so make the shape to suit your preferences.

Once cut, glue it on the piece of foam that will go into the f-hole. This will give you something like that :

Boucher les f-Holes d'une guitare

Then make the same work for the other f-hole. I used the same paper sheet for both holes as they were strictly identical.

My guitar with both plugs :

Boucher les f-Holes d'une guitare

In the end, those plugs are reliable, disrete, cheap and can be quickly fixed/removed.
With this solution, you’ll be tempted to put more distortion and your band will then play a jazz-grind-rockabilly-doom type of music. You’ll thank me.