Newly carved Guitar shaped Octave Mandolin top Buzzing

**Matthew Jenkins** · Aug-05-2019, 3:21am

Hi
I'm currently building an Guitar Shaped Octave Mandolin with a carved top. I used X-Bracing and whilst tuning the braces I noticed a buzz when tapping. I couldn't get rid of the buzz so decided to strip the braces and re do them. However, the unbraced top still buzzes when tapped.
It seems to be coming from one of the f-holes which I have bound with black fibre veneer (although I'm not certain this is where the buzz is coming from).
I wondered if reinforcing the f-hole with cloth tape would be a good idea?
I'm a bit worried that the top will continue to buzz when I have completed the instrument which would be a disaster.
Any ideas on what might be going on??
Thanks in advance for your help.
Matthew

**John Bertotti** · Aug-05-2019, 6:41am

A void in the wood? Maybe inspect it with a bright light behind it might find a small check or crack somewhere as well.

**Matthew Jenkins** · Aug-05-2019, 2:13pm

Thanks John
I'll have a good look tomorrow. On first inspection I can't see anything but I will get a stronger light and have a better go.

**John Bertotti** · Aug-05-2019, 3:09pm

I’m no instrument pro but it’s a place to start especially if you have already removed any bracing. I would be inclined to rig a jig with a set of strings attached so I could put the top under string pressure before even using it. It would be a shame if it failed when under pressure or even a few months after having a completed instrument.

**Charles E.** · Aug-05-2019, 5:22pm

Could be a hidden sap pocket or a hairline crack. Hopefully you can locate it with a strong back light. It would be a shame to have to start over with a new top.

**Harmon Gladding** · Oct-23-2019, 10:34am

Try tapping it in a different room.

**Marty Jacobson** · Oct-23-2019, 1:48pm

Originally Posted by inangaman

Try tapping it in a different room.

And holding it and tapping it in different places, including damping the fiber inlays with your fingers. Possibly it's a dry glue joint along the inlays somewhere.
Could also be a split somewhere in the wood.. sometimes they'll sneak up on you.

**HoGo** · Oct-24-2019, 12:55am

Is the top attached to rim or free? As previous posters suggested you may have loose centerjoint or tiny crack at perimeter that is not visible. You can try flexing the plate edges slightly to see if any crack opens. The edges of fholes are especially fragile and such crack can occur during cutting of f holes and go unnoticed.