i like cyanoacrylate (superglue, crazy glue, etc.), but I only trust it unquestionably for non-tension filling and some very light adhesion, on mostly cosmetic things.
I've repeatedly seen the mixture of baking soda and cyanoacrylate crumble under string pressure with bridges and nuts; as such I no longer trust that mixture.
If for quick and dirty emergency fixes where tension is involved, I'll only use cyanoacrylate with powdered hardwood or powdered bone shavings, and then, be prepared to fix it properly ASAP.
On an item like a nut or a bridge, it's necessary to "dam off" the area that needs to be built up. Usually masking tape can do this, but the cyanoacrylate, which is very thin, will probably still leak and be a mess to clean up, so be prepared for that; if possible separate the part being worked on away from the rest of the instrument, and use gravity to try to avoid getting cyanoacrylate all over any nice finished areas...
Of course if it's a viol-family bridge being worked on and if it is removed for this work, be aware of your sound post situation.
Shape the powdered hardwood or bone shavings inside the "dam", then drip a very few drops of cyanoacrylate over the shavings until they are minimally saturated. Keep in mind that the more cyanoacrylate you apply, the more will leak.
Cyanoacrylate mixes like this tend to shrink as they dry. As such, multiple layers may be desired to achieve an optimal effect.
Give it a few minutes to dry, and then remove the masking tape. Then get your needle files and fine sanding films out to do the final shaping.
Of course also be prepared to have your fingers stuck together, or to whatever you're working on.
