This is the mistake most painters make. They economize when using paint. They end up 'scrubbing' the surface which forces the color in the brush hairs to mix with the surface paint on the canvas. The result often appears muddy or chalky.
The pigment clumping (chalkiness) you're seeing happens due to the drying time of the very wet mixture. If the paint dried more quickly, the pigments wouldn't have time to draw together like that (bearing in mind that the individual pieces of pigment are smaller than the chunks of texture you're seeing).
Remove all chalk residue by one of these methods: Excessive chalking requires pressure-washing or sand-blasting. If a pressure washer is not available, scrub the surface with a stiff brush and a mild detergent. Rinse thoroughly with a strong stream of water from a garden hose.
An easy way to restore/ fix this is to cut and buff with a cutting compound. Any brand will do, im using a generic brand available form my lcal automotive parts store SuperCheap Auto. This can costs under $20. A final polish and/or wax is also recommended to prevent any future chalky paint residue.
Just sand it enough to get it scuffed up; this should be enough for your primer and/or paint to adhere well. If you're trying to paint over chalk paint that has been sealed with was, it's going to take more prep work than a light sanding to get it ready for the new paint.
Remove paint chalking by washing or power-washing the surface with an appropriate cleaner. If some chalk remains after first washing, then wash again for complete removal; scrubbing may be necessary. Rinse well with water. Allow to dry thoroughly.
Why does it occur? Chalking occurs due to ultra violet (UV) radiation from sunlight interacting with the constituents within the paint film. Over time UV degradation of the binder or resin within the paint film will allow the exposed pigment particles to become more loosely bound to the surface.
One of the questions we get a lot is “Can you paint over Chalk Paint”? The simple answer to this is YES!
Chalky surfaces occur when a paint film breaks down, usually through exposure to excess moisture.
Solution: If the paint is still wet, try to dab or wipe with a damp cloth to remove the mess. Otherwise, allow the paint to dry completely, lightly sand the problem area, remove the dust with a cloth, and then touch up with a clean brush and paint.
Remove Chalking
Remove chalk residue by rinsing or power washing the surface with an appropriate cleaner. If some paint chalk remains after first washing, then wash again for complete removal. Scrubbing may be necessary.
This may be due to any of the following factors: Moisture trapped beneath the surface of the paint film. If the paint is applied over a powdery or friable surface. Surface contamination such as dirt, oil, and grease.
Chalk needs to be removed before repainting and can be considered to be in the same category as dust and dirt. The use of Resene Paint Prep and Housewash is recommended as part of the chalk removing process. Simply dampen the surface with fresh water, and scrub - ideally with a soft bristled brush or broom.
You can easily apply wax to your dried chalk paint by wiping it on with a dry cloth and buffing it in. A small amount of wax can go a long way so be cautious when using it.
To use vinegar to remove chalk paint, you should mix equal parts vinegar and water together in a spray bottle. White vinegar works best because it has the highest acidity, but cider vinegar works well, also. Spray this mixture all over the paint you want to remove, and then let it sit for at least 15 to 20 minutes.
Prepare a foam eraser and a window cleaner or natural chalkboard cleaner. Spray the eraser with the cleaning solution. Scrub off tough stains and marks using the foam eraser. Wipe the board with a dry microfiber towel.
Chalking is a loose, white powdery pigment residue on the surface of a coating accompanied by a loss of sheen and color. This can be expected to occur over time and is a normal way for paint film to wear. In some cases, this is a self-cleaning feature designed into the coating.
Both can work, but acrylic paint's elasticity and resistance to wear and tear make it better for high-touch areas and furniture. Latex paint works well for larger indoor projects where low toxicity and easy cleanup with a brush are priorities.