ukulele bridge HHG issue

[charley erck]

The recent hide glue discussion has prompted me to get out this old uke, made probably in the 1930s of Koa, and try gluing the bridge again. Last year I carefully located and glued the bridge with hot hide. I played it a short while and the tone is magical !  Then the bridge came off again, to my dismay. This instrument had been sitting in it's box case for untold years with the bridge off when it was given to me.

When the glue gave out so readily , I got afraid there is something about the hard Koa curl in the top wood that resists sticking, and couldn't decide how to proceed. Anybody have a take on this?

I got my glue, by the way, from Frank Ford years ago.

Would appreciate any guidance on this.

[Paul Verticchio]

BEAUTIFUL UKE, Charley!!!!!  :)

I'd give it another try.  I know I'm likely preachin' to the choir, but pay special attention to scraping away the old glue so a fresh surface can be seen. Also a quick wipe with naptha before gluing will abate any oily wood issues. Also note Franks advice on pre-heating the bridge and alternatively using Fish glue instead of HHG.

If that is unsuccessful, I'd epoxy some non-oily wood veneer (1/64th max) to the bride's footprint on the uke's top and to the bottom of the bridge to eliminate the possibility of oil contamination.

Again, she's a beauty :)

[Jeff Highland]

I have not found koa to be oily or present any gluing issues.

It looks like you have glue adhered to both surfaces perhaps you did not get it together and clamped quickly enough or it moved during clamping.

HHG does have a bit of a learning curve and a bridge is not the easiest situation.

[Kerry Krishna]

 My goodness Charlie, this is a beautiful axe. How about a few detail shots? Fretboard/headstock/back/and the case looks super interesting!...

[jbbancroft]

When preparing a bridge for gluing I dry clamp first, then work a thin feeler gauge around the perimeter to make sure it is tight to the top and no gaps. If there are gaps I'll sand the bridge base or top until I get a tight fit.

When gluing with hot hide glue you need to mix the glue water thin, so that it doesn't setup quickly. Also make sure you warm the top and the bridge before gluing.

I don't recall ever having a bridge come loose using this procedure. Mixing the glue thin is the secret, just make sure it is still slippery when rubbed between your fingers. Also apply clamps quickly.

Jim

[charley erck]

Thank you all so much for responding. Looking back, I think it possible the glue was on the thick side, and maybe I was slow in assembly. I'm buoyed up and ready to try it again! 

Yes it is a beauty, koa fretboard and body.Crisp toned.

[jbbancroft]

Too thick a glue mixture will cause problems. Water thin, but yet slippery between your fingers is the correct consistency, for all glue jobs. Otherwise it sets up too quickly.

Looking at your pictures, I can see voids where the bridge appears not to be in good contact with the top.

Jim

[Jeff Highland]

I like it to be more like maple syrup than waterthin, especially for bridges.

But I do vacuum clamp and so have it together and clamped really quickly.