Latex paint will hide hairline cracks in plaster, at least temporarily. The coverup, though, may last only a few hours or a few months. Small plaster cracks have an annoying way of showing up again and again. It may be smarter to enlarge them and fix them properly once and for all.
No that's bullshit. Paint won't prevent plaster from cracking. If it's done cracking, and they really are just hairline cracks, the paint will probably cover it well enough where you'll no longer notice.
There are specialist paints on the market like Bedec Interior-Flex, which are designed to not only bridge hairline cracks, but they also resist the cracks opening up again.
Hairline cracks of less than one millimetre in width or slight cracks of between one and five millimetres are generally not a cause for concern. If you begin to notice these, they can generally be filled and painted over as they're a crack in the plaster but not in the wall itself.
On average, plaster casts stay on for about six weeks. This time is sometimes longer or shorter, depending on your age, general health and type of fracture. During this time, x-rays are done to check that the bone is healing well.
For surfaces with hairline cracks, when the wall is repaired, choose the flexible primer system that can cover up hairline cracks to make the wall smooth.
KILZ OVER ARMOR® Textured Coating is a lightly-textured, solid color coating designed to bridge cracks, hide imperfections and give a uniform look to old, weathered wood. KILZ OVER ARMOR Textured Coating can also be used over cracked and weathered concrete. Available in a variety of “wood stain” and “concrete” colors.
Most cracks can be dealt with using patching plaster or a specialist wall/ceiling filler like Toupret interior filler powder which provides a good finish to paint over.
If there are any cracks in the wall surface, these should be filled with spackling paste before proceeding with the skim coating process. Once this is done, use sandpaper to lightly scuff up any glossy surfaces so that they have more texture for better adhesion of the joint compound.
Flat or matte finish paint will not be as easy to clean and will show scuffs much easier than satin paint, but the lightly textured finish can be very useful for hiding minor imperfections in the underlying plaster.
One of the best ways to fix cracks in plaster walls is to start by scoring the crack. This will help to remove any loose plaster and create a larger surface for the joint compound to adhere to.
To fix cracked paint, remove loose and flaking pieces with a scraper or wire brush. Then sand the surface and feathering the edges. If the flaking occurs in multiple layers of paint, you may need to use a spackling compound to create a uniform surface.
Polycell Crack-Free Ceilings is a great way to restore cracked ceilings to a smooth 'good as new' finish. This flexible matt paint formulation uses uses Polyfilla technology to not only cover cracks but prevent them from reappearing.
KILZ Mold & Mildew Primer prevents mold and mildew growth on the primer film/primer surface. It is important to ensure that the surface is mold and mildew free before the primer and topcoat paint is applied. It is however, not supposed to be applied directly to mold (especially the black or yellowish, wet, slimy type).
Zinsser Peel Stop - Unique Clear, Water-Based Binding Primer
Stops peeling, cracking, and flaking on a variety of surfaces.
Besides cement grout, you can go with any other filler material or sealant to fill out the cracks. Keep in mind that an ideal adhesive needs to have low surface tension and viscosity. These properties help the adhesive to penetrate deep into the gap to fill it.
Cracks in plaster
Simply enlarge the cracks slightly using a scraper (fillers don't work well in hairline cracks), dust off and fill with a suitable product such as Polycell Trade Interior filler. Dampen the hole or crack with water - this will help the filler to bond.
Small cracks in plaster ceilings can be easily repaired by applying new plaster and repainting the ceilings. Larger cracks should be dealt with by a professional to ensure there are no structural concerns.
Treatment. If you are diagnosed with a hairline fracture, it is important to rest the injured area to give the fracture a chance to heal. For the first 24 to 48 hours, keep the area elevated and apply ice to reduce the swelling. After around two weeks you can begin gradually introducing weight-bearing activities again.
Generally, a plaster should stay on for about 24 to 48 hours to allow the wound to start healing and help protect it from infection and further injury. Make sure the wound is dry within at least two days. If the plaster becomes wet from blood or any other liquid, it should be changed immediately.