Rawlplastic ?

If you have a hot-melt glue gun, fill the holes with glue and push a plug in while it's molten. Then run your thumb under a cold tap for a minute or so.

This works very well and is quick.

I think this is the same stuff I have an ancient packet of, which was good for filling then re-drilling quickly afterwards

part of the description on the wilko website seems to belong to a different product? "Can be used as a two product system For use on heavily rotten wood and large areas of decay."

I gave up after having to do that a nuymber of times over the years. Whatever I used came loose again after a while. The offending rail is now held up with far longer screws, screwed right into the catnic - it's going nowhere!

If the plaster is from possibly 50+ years ago I've found that it's better to make the hole much larger, seal round the inside with PVA and letting it dry before filling. Then after drilling for a new plug select a better quality one and possibly not one of those generic red/yellow/brown/blue that that you often find in pound shops.

Blow the dust / debris out of the holes.

No More Nails in the holes, then new plugs. Leave 24 hours- longer if possible.

Before injecting hot melt glue in there, heat up the local area of the wall and hole with a hot air gun and temprarily blank off, flush with the wall surface with some kitchen silicone bakeware material, with a hole in it to take the plug, and alignment markings.

Car body filler

But will it hold a wood screw? Rawlplastic would hold the screw even before it set, due to its fibrous nature.

The fibres being asbestos though.

Just use filler with added pva, then redrill for new plugs. Key is to make the scews deep enough to fix into the masonry.

IIRC mainly asbestos. The GPO banned it.

Hmm, I've used all sorts of things, from an epoxy resin like car body filler, to the old item you mention, Plastic wood it used to be called. The main issue I nearly always encountered was that the plaster itself further away from the jagged hole had blown and not fixing that first meant in a short while a bigger hole was created in the wall. I have one at the moment where a speaker bracket pulled its top screw out.

that was a proper rawl bolt too, and part of the underlying brick of the party wall has come off with it.

Brian

Cut back to firm plaster (at least a couple of inches) and soak with PVA, then fill with Polyfilla-type stuff. You can either push plastic plugs in while it's still soft or drill when it's thoroughly hard.