Double Bass gluing fingerboard, what did i do wrong

[Blaine]

i glued up my fingerboard. fresh hide glue. clamped it. seemed to be fine but today, about a month later it popped off. first at lower third but then i was able to pop the rest off very easily. the neck is coated with glue and seems good but the fingerboard looks like there has never been any glue on it at all. any ideas on what i did wrong? i'll try to add a couple pics.

 

[flint]

my guess would be that you applied glue to the fingerboard, and it "went off" before you could get it clamped to the neck.

 

[1st Bass]

Heat both pieces before applying the glue-- they should be uncomfortably warm to the touch when you apply the glue. The glue will then stay liquid long enough to get the clamps on, etc. and complete the bond after you are exactly where you want to be.

I use a heat gun-- in the past I used a clothes-iron. Both work.

 

[GriffithLea]

IANAL but I think in addition to the pieces needing to be warm, they need to fit together extremely well. Hide glue depends on a good fit, if I am properly remembering my Bollbach.

 

[Jake deVilliers]

Good points above, plus hide glue really seems to like a freshly prepared surface.
A quick scrape or sand with 320 will help it bond well.

You have to move really quickly with hide; it won't tolerate lollygagging.

 

[Uncletoad]

It sounds like it set up before it bonded to both surfaces.

The set up time is really quick. If it's gelling your too late. I'm talking 30 to 60 seconds from when it leaves the glue pot.

Make sure you're pot is hot enough. 155 to 170 deg F depending on the glue.

Don't use crap glue. Buy the good stuff.

I use this guy's stuff [Invalid or Expired Link Removed]

Many use 5% urea in their mix to slow the set time and get a bit more clamping time before it sets up. That can buy you as much as twice that setup time in exchange for a bit of reduced glue solidity.

As has been said prep work is key. Heating the surfaces is a great idea to buy a bit more time. I usually set up my procedure and have the clamps/jig ready in as complete a system as I can. I usually do a dry run or two if it's not something I do every day. Heat things up, apply the glue and get clamped up as fast as possible. Cleanup only after the jig/clamp system is set, any wasted time kills the joint.

Anytime I'm doing that around the shop and somebody tries to ask me a question while the glue is open they have to clean the bathroom from edge to edge.

 

[arnoldschnitzer]

If you glued the fingerboard just as it came from the manufacturer, that may have been the problem. Most fingerboards are dipped in a vat of black dye, which is not compatible with glue. It is necessary to plane or scrape the mating surface of the fingerboard to get the dye off and to make it flat.

 

[1st Bass]

I was wondering what that nasty stuff was! Thanks, Arnold!

 

[robobass]

Just curious. Is it a good idea to moisten the surfaces as well during prep? I always do this with very hot water just before I apply the glue, and then get the clamps on with same the kind of expedience I would exhibit were I flushing dope down the toilet while cops were busting down my door. No one ever told me to do this, I just have always done it, and anyway it doesn't not work.
Robobass