If the paint is too thick straight out of the can, it may need to be thinned using the appropriate thinner (water for latex paint, mineral spirits for oil-based paint, etc.) to reach the right consistency. Additionally, using the right tools and techniques for application is crucial for achieving a smooth, even finish.
Signs of damage: If the paint has gone bad, it will look curdled like cottage cheese or overly thick like a pudding. If you dig out an old can of paint and you have either of these, it's best not to use the paint and dispose of it properly.
Add a bit of water to the paint and then mix it together with a palette knife. You may have to use a grinding motion a few times for the water to mix in with the paint. You can also use a palette knife if you add an acrylic additive, as described above.
You might notice the consistency of your paint has changed. There may be a “skin” on the surface or lumps that won't stir out. If either of these is present, your paint has most likely expired.
Thicker layers of paint take longer to dry because the solvent takes more time to evaporate from the deeper layers, and the curing process is slower. It's important to apply paint in layers of recommended thickness. Safety Considerations: As paint dries, it can release volatile organic compounds (VOCs) into the air.
The texture and finish of the painted surface can be negatively impacted by overly thick application. For instance, it might obscure details on textured surfaces or woodwork. To avoid these issues, it's important to follow the manufacturer's instructions regarding thinning and application.
Make dried paints liquid again with water
As acrylic paints are water-based, you can make these paints liquid again by adding water. Hot water is best for this, which you pour drop by drop into the pot. Then stir the dried paint thoroughly and wait for the water and dried acrylic paint to mix thoroughly.
Is it lumpy? Paint should be creamy and smooth. If you stir it and it's full of lumps – it's bad – get rid of it.
The bottom line is that watery paint is unusable. So if your paint is too watery and you attempt to use it to paint your home, you will notice that the paint won't adhere to surface correctly. It will be 'thin' and therefore will perform poorer than expected.
"Paint that is beyond its shelf life can develop a rancid, sometimes rotten-egg odor," says Edrosa. If you open a can and find either of these problems, dispose of the paint and buy new.
Things You Should Know
Only use water to thin latex paint since it's water-based. Adding chemical paint thinner or other solvents will ruin latex paint. Gradually stir in about ½ cup (118 mL) of water per gallon (3.8 L) of paint until the paint is the desired thickness (don't dump in large amounts of water at once).
If the paint feels lumpy, strain it before working on your project. You can also add somewater or a paint thinner to restore its consistency. You can use a pair of scissors to remove any lumps while the paint is still dry. After the paint has dried, you can smooth out the canvas using sandpaper.
It may look different when you first open the lid but use a suitable paint stirrer to mix everything together and check the consistency again. It should flow freely but not run like water or have lumpy globs. If it looks thick and lumpy, don't try and paint with it.
For one, the expired paint will have adhesion issues. More importantly, it can be hazardous by giving off excess VOCs or paint fumes. In this case, it's best to get new paint. However, the paint may still be good if the water has separated from the solids.
While it's tempting to splash your second coat as soon as you've applied the first, you will be doing more harm than good. Painting over wet paint that hasn't thoroughly dried can cause bubbling, cracking, streaks, or clumps, resulting in an undesirable finish.
Don't store the paint too long.
Even with the lid over the can, latex paint will thicken if it isn't used for multiple months or even years. The condensation within the paint will still manage to escape and you'll be left with a thick putty-like substance.
Chunky Consistency
Old paint is likely to separate. This is also a good opportunity to check the consistency of the paint. If, after stirring the paint, the consistency is chunky, lumpy, or has a cottage cheese-like texture, the paint has expired.
Add a half cup of room temperature water for each gallon of paint. Stir the paint thoroughly. Be sure all the water is incorporated. Watch how the paint runs off the stir stick.
If your acrylic or house paint has dried up, don't worry – you can bring it back to life. Simply add a bit of water or a paint conditioner to the dried paint and stir it well. Start with a small amount, mix, and check the consistency. Repeat until it reaches the desired smoothness.
Go slowly and be careful when adding water because this is only a one-way process: You can always add more water to the paint to further thin it out but you cannot thicken the paint again.