View Full Version : Wavy top below bridge?

09-07-2017, 06:15 AM
After two days in "Tech Forum" without reply, suggested to move question here.


Q: Just purchased this used Pono Baritone and noticed there is no glue (white area in photo) under part of the bridge. In addition, what cannot be seen is that there are two vertical lines below the bridge pushing upwards so there is a bit of a wave on the top under the bridge under the 1st and 4th strings. Two vertical lines push upward below bridge to base of instrument at 1st and 4th string with dip in between under strings 3 & 4. I incorrectly assumed there would be tone bars under these lifted areas but found only a center brace.

Action and truss rod function is fine.

Looks like it was over humidified (in HI for two years before receiving it). Hoping it will settle in the more desirable level I maintain here.

Q: Is this common on other Pono Baritones?

Q: Reason to be concerned?

Q: Suggestions? Seller said it was "excellent" and basically "New."

Michael N.
09-07-2017, 06:35 AM
Going by that photo it looks like the bridge is starting to come off. The white stuff is (perhaps) glue that is trying to fill a gap.

09-07-2017, 08:08 AM
We could do with more pictures, showing the view across the top at that point. From this picture I can't see the waviness. If one of the pictures had a straight edge across the waves, that would help.

From your description, it sounds as if the top has tried to swell (you mention high humidity) and, with nowhere to go, has distorted the best it could, opening up the glue line under the bridge.

It it were mine, I'd begin by sliding a feeler gauge into the gap to see how bad the separation was. If the gauge only slides in 1/4 inch, the bridge might stay on forever. If so, I'd just check it regularly and do nothing until it got worse.

If the separation was substantial I'd want to remove and re-glue the bridge. No point attempting this until the top is flat, so I'd slacken the strings right off and see what happened. There's a chance that without tension the top will slowly come back to near flat - if so, off with the bridge, out with the hot hide glue, and I'd have it sorted in a day.

The other thing I'd check is the fan braces (I'm assuming from your description that it has three fan braces) and the bridge plate (if it's got one). If these have come unglued it's a far more complex repair, and I'd get it off to someone with experience in that kind of repair. If it were a cheaper instrument I'd do it myself.

I'm guessing you're not a builder or repairer as you're asking questions and not giving the information I'd give and know a more experienced repairer would want. If so, the best you can do is use a feeler gauge to check how bad the bridge separation is. If minor, live with it and check regularly. If not minor, find a repairer to fix it for you.

09-07-2017, 08:31 AM
THANK you for the detailed reply. The fan braces are tight and no sign of wood degradation or swelling viewing it from inside with lighted mirror.

Very small gap on bridge - paper thin and goes under less than a mm. Maybe 1/2" wide.

Expert advice is sooo appreciated. I will follow advice given here and watch and wait. If problem worsens I will be sending it to one of you.

Major thanks!102883102884102885

Patrick Madsen
09-07-2017, 10:12 AM
Is the baritone ladder braced? I have a Webber with two slight "waves"; it's caused by using a ladder braced system along with a light build. Webber has changed his design to a fan braced system now.

09-07-2017, 10:56 AM
Good question. Fan braced with diagonals extending at approx. 45 degrees out below bridge to base. Only the center brace is any where near the wavy top of the lifting part of the bridge.

09-07-2017, 11:05 AM
I have a mini-concert ukulele with more wave and a larger separation than that, been fine since 2009.
Yes, a Baritone has more string tension, but if it plays nice, sounds good, I would not worry too much.
Provided the "waves" and the bridge separation does not get any worse, no reason it will not just stay like that.