How do I fix this hole in a plaster wall corner?

[ArchieDBunker]

Help would be appreciated - what do I need to do here?

 

[Wayners]

Scrape lose off. Got any wood glue? 50 / 50 with water and lash on right in gaps.
Let it dry for a few hours.
Toupret powder mix real thick (bread dough like) and poke in and around and let it set. You don't want enough filler that it sags with weight. Just put some in best you can, right in. When set (but don't leave to dry) so 90 ish mins and do again. When set 90mins do again and smooth off. So you are building up a bit at a time.
Take a few days to dry. Sand 120 grade.
Could then run lining paper over its up to you

 

[ArchieDBunker]

Thanks @Wayners - exactly the info I needed. Just one question if you don't mind - why mix the glue with water? Is it easier to apply that way?

 

[Wayners]

Glue needs to be thinned a little or like plastic. I say wood glue as pva and saves buying loads for such a small job

 

[ArchieDBunker]

@Wayners Thanks for the reply!

 

[JP_]

Expanding foam!

 

[ArchieDBunker]

@jonbey - Thanks, I though about that,but I'm going to need to drill and hang a heavy curtain rod afterwards and I'm worried the expanding foam won't be strong enough to support it?