My local bit of soft, large grained, somewhat crumbly sandstone is losing a half tip (vital) flake. Currently it's flexing slightly, I think if it comes away it will also fall apart. Advice needed, is their a way I could reinforce, re build the hold a bit (it's already broken once)? I've successfully in the past used the sika stuff to stick broken holds, but this didn't work on the section that's broken already, I suspect it's too grainy.
It's not a popular spot at all, and it's in France so their are no ethical issues involved