Good type of filler

Mark presented the following explanation :

The idea is not to fix anything to the plaster, but to drill through it and into the brick or concrete under the plaster.

Indeed, but the plaster layers are very deep and I'm not sure what to use that would be deep enough to avoid the plaster layers.

Mark formulated on Monday :

Longer screws and a longer drill bit if necessary.

Polyfilla is actually quite strong. If you can get it keyed into something structural (like the laths in lath and plaster), or applied to good brick or blockwork, then it will take wallplugs, as long as the load isn't too silly. It would take net curtains on light rails, for example.

Car body filler might be another option, get a big tin from eBay, not a small one from Halfords. But you *do* have to make sure it is attached to something. Assuming your curtain rail is over a window (rather than a door, say) the plaster is almost certainly attached to bricks, blockwork, or possibly a wooden lintel. This should be strong enough apart from any areas of rot or woodworm. You may need quite long screws. Another good fix is to put a wooden batten behind the rail, then you can fix that at strong spots while being able to space the rail hangers evenly.

Somebody recommended 'One Strike Filler' to me and I'm quite impressed with it. It looks like a merengue but sets hard.

Red Devil is very good - much better than Polyfilla.

I do like it as a filler, but if I remember correctly the label says do not use it to nail or screw into ...

IME polyfilla & similar are just fine, as long as your wallplug goes into a hole that's filled partly with it. You can toughen it up a good bit by mixing it with PVA. Give it a couple of days minimum before drilling or fixing.

NT

bonding plaster

Don't be silly. Sets much too hard and cannot be sanded.

use Wickes fine surface filler. Strong as gypsum plaster but can be sanded smooth.

Yes, I think that's right but I think others are saying to use longer screws so I assumed the filler was for decorative purposes.

Oh yes it can

Then by your own words, it cant be as strong as bonding plaster.

Yes.

Previous owner here had uPVC windows fitted, including a bowed outwards window at the front and a patio door at the back. I had problems with curtain poles keep coming loose. Luckily, the work the previous owner had had done had necessitated catnics at both openings and the poles haven't moved since I drilled right into the Catnics and screwed to those!

SteveW

I get along with it fine but I only add enough water to make a stiff paste that only just doesn't stick to the filling knife. Spray water onto the existing substrate so that doesn't suck the water out of it. I also treat it like plaster, fill smooth and only a tiny bit proud. Then let it partialy set, a light water spray and polish flush with a flexible knife.

I guess you want something to refix the plugs/screws? Polyfilla will do that but use it to fix the plug back into the dust/loose material free hole. Well damped hole, very stiff mix, use something to push filler right to the bottom of the hole and partially fill so that the filler oozes back out as you push the plug in, might be a hard push with a stiff mix...

Bonding goes off pretty fast, even in 50mm layers. Skim with polyfilla for a smooth surface

You can't fix anything much to plaster. The fixing has to go through the plaster into the brick.

Maybe, but it's always worked for me before with "normal" plaster.

You've been very lucky, or only fixing light things. I'd not expect it to work for a curtain rail which can have quite a load on it.