You can use a ``thick'' superglue to glue the pieces together. The watery superglues simply get absorbed by the plaster. Still, i would recommend vacuum/wetwipe the broken surfaces. Plaster tends to have a very thin layer of dust, preventing the glue to bond on the actual surface.
PVA glue – I use plain old Elmer's school glue. Plastic syringes or a spray bottle – Syringes work best. Construction adhesive – My favorite brand is Loctite Power Grab. The formula works for many applications, including plaster.
Your best bet is to pre-drill through the plaster and into studs (full fastener depth), and then screw into studs. Your next best bet (if things don't line up) is to drill and screw into existing trim - that's one reason the trim in older homes is so much larger and flatter than it is on modern construction.
However, a plaster filler like Polyfilla or a powder filler are probably the best options for filling plaster cracks, as alternatives such as caulk are best used for other purposes, like sealing gaps around pipes or tiles.
If the plaster is very old and damaged, it is important to fix any cracks and holes before plastering over it. Smaller holes and cracks in a wall can be filled using a sealant such as Caulk. Larger holes and cracks will have to be filled with plaster and mesh, which may be a job for a professional.
You can caulk over cracks in plaster but it's not the ideal solution if you want a smooth wall or ceiling. Typically the caulk will sink a small amount into a crack leaving an indent in the surface.
As mentioned earlier, avoid using nails on plaster wall because they will likely cause the drywall to crack. Instead, use a screw, because they won't break the plaster wall. Screws will also hold a lot better because they will fasten into the lath behind the drywall.
It's fair to say that it's pretty easy to fix cracks in plaster walls. The good news is that if you're lucky enough to only have a small section of blown plaster, you can easily fix it using a skim coat of PVA.
Toggle Bolts: Toggle bolts are among the most reliable anchors for plaster walls.
USG Plaster Bonder: Pink is a vinyl acetate homopolymer emulsion used to bond new plaster to any structurally sound interior surface. It provides enhanced plaster adhesion to surfaces like gypsum plaster, cinder block, stone, drywall panels, and other similar materials.
The problem of the crumbling plaster can also be resolved by applying a mixture made of water and vinegar to the defective area or region. It shall act as a shield against the dampness of the wall by making the surface area much stronger than before.
Small, minor cracks can be easily dealt with by a plasterer or general builder, but serious cracks need to be assessed by a structural engineer. To make your room 'good' again, hire a painter and decorator to give it a new lease of life.
Use a suitable plaster filler or patching compound to repair small cracks and bubbles. Ensure a smooth finish by feathering the edges of the repair, blending it seamlessly with the surrounding plaster.
Ready mixed plaster is plaster that does not required to addition of water to use. The plaster can be used directly out of the tub or tube. Our range of ready mixed plasters can be used on rough, smooth or tiled surfaces.
Browning plaster
It's very similar to bonding plaster, but more absorbent, and thus most useful with more absorbent surfaces. They are used by professional plasterers as an undercoat for paint and adornments. It's a versatile base for painting, good mouldings and decorations.
From below, drive 1-1/2 to 2 inch gyp-board screws, fitted with plaster washers, through the plaster and lath up into the joists. Space every 4 inches on each joist where sagging is apparent, or as often as necessary, and 1-1/2 inches from the edge of the loose section (only screws that hit lath will hold).
For lighter items, screwing into the plaster with a 1 1/4” drywall screw can get the job done. For heavy items, you can opt screws with masonry anchors.
Framing nail guns are also excellent for projects involving plaster, as hand hammering can crack and loosen plaster.
Sheetrock® Brand Durabond® Setting-Type Joint Compounds and Sheetrock® Brand Easy Sand™ Lightweight Setting-Type Joint Compounds are the best products to use for repairing cracks. If you want to use a ready-mixed joint compound, Sheetrock® Brand All Purpose Joint Compound works well.