Double Bass Scroll/Headstock Crack Repair

[robobass]

Tbh, when I posted this, I was thinking of using CA Glue for the project. When I started reading up about creep though, I found this link (Invalid Link Removed) and got worried when I read the following:

“Curing requires that the moisture found on most surfaces is neutral or slightly alkaline. Any acidic substrate, such as many hardwoods (e.g. oaks), will tend to inhibit the cure and in extreme cases prevent curing altogether. ...

The mention of creep worried be, but in hindsight, by “elevated temperatures” and then following it up with 110 deg C, I don’t believe that they’d claim 40 deg C as “elevated temperatures” but I don’t know. I also don’t like the bit about it not curing to acidic woods…

I do of course appreciate that you did a similar repair and it was fine for at least 10 years of course. CA Glue would be a lot easier for me, but I do like that HHG can be reversed if I should ever need it (even though I don’t know why I would).

One general thing I should mention is that I probably won’t be able to do this repair for a few weeks. I may opt to continue with HHG, but if I don’t have that prepared yet and I notice the cracks spread, then I’ll just put CA glue in there, as I already have some, and could get more within an hour.

I wouldn't worry about it. Lots of luthiers/woodworkers use CA to bond hardwoods. The only thing is that they work better if the parts are slightly moist. I spend much of my week bonding wood to leather, metal to leather, and leather to leather. It all goes best if I spray a water mist on the leather before applying the glue.

If you brought this job to me then CA would be what I would choose. When you remove the tuner rings I'll bet that the gap closes significantly. You will want to find a way to open the crack in order to apply glue.
"Just put blue masking tape right next to the crack on both sides to keep the glue from running all over"? [/QUOTE] Well, I find this rather dubious advice. Painter's masking tape isn't going to contain the flow of thin CA.
Anyway, Maybe enlist two friends to hold the gap open using needle-nosed pliers in reverse while you apply some Super Glue. If you can do it quickly enough and get the clamps on then you can wipe away the residue before it sets. It might be the case that you don't even need clamps.