Keris with elephant-headed blade.

[Athanase]

Since I received it, the ivory has given way.

In fact, the handle had already been completely broken in two (or even three pieces), then glued back together. And it might not have been the first time it had been glued in that spot, because on the side I can see an older repair with a small ivory nail to help hold the two glued parts together.
On one side there's also a missing piece that's been filled with a piece recarved from bone.
Now that I've removed the two parts of the handle, I'm thinking of trying to remove the old glue with acetone and then attempting a clean re-glue using the glue we use for fossils at my work (acrylic glue: Paraloid B72).

[A. G. Maisey]

I thought that might have been the case when I followed the cracks.

I have repaired more than a few hilts in many different materials, my adhesive of choice is 5 minute Araldite. The joining surfaces must be absolutely clean & dry, I like to roughen the joining surfaces with cabinet paper or a sharp pointed tool before applying the adhesive & this adhesive can be tinted with artist's powder colour. Hold firmly in place by hand until the adhesive sets, before that adhesive hardens I go over the hilt using a 2x or 3x loupe & dentists picks and clean away any excess adhesive. Sharpened bambu sate sticks are also good for this purpose.

Re roughening surfaces, it is best to leave the one or two millimeters adjoining the visible edge of the crack without roughening in order to make it easier to get a tight fit of those visible edges.

[Sajen]

Originally Posted by Athanase

Since I received it, the ivory has given way.

In fact, the handle had already been completely broken in two (or even three pieces), then glued back together. And it might not have been the first time it had been glued in that spot, because on the side I can see an older repair with a small ivory nail to help hold the two glued parts together.
On one side there's also a missing piece that's been filled with a piece recarved from bone.
Now that I've removed the two parts of the handle, I'm thinking of trying to remove the old glue with acetone and then attempting a clean re-glue using the glue we use for fossils at my work (acrylic glue: Paraloid B72).

Please show us the result! Maybe also pics of the broken hilt.