The answer is: It depends on why the old paint is thick. If it's simply settled and can be properly mixed back to its original consistency, then possibly. However, if the thickness is due to damage or spoilage, then no, it is not recommended.
Here's a more detailed breakdown:
-
Settling vs. Spoilage: Paint often separates over time, with the pigment settling to the bottom and the liquid portion rising to the top. This is normal, especially for paints that have been stored for a while. However, if the paint has gone bad due to age or improper storage, the thickening may be a sign of irreversible damage.
-
Signs of Spoilage:
- Appearance: Look for a curdled, cottage cheese-like texture or an excessively thick, pudding-like consistency that doesn't mix back smoothly.
- Smell: A foul or rancid odor is a strong indicator that the paint has spoiled.
- Lumps: Hard, rubbery lumps that don't dissolve with stirring suggest the paint has deteriorated.
-
Reviving Settled Paint:
- Open Carefully: Old paint cans can be under pressure. Open slowly and carefully.
- Stir Thoroughly: Use a sturdy stirring stick (not a screwdriver) to mix the paint. Work from the bottom of the can to re-incorporate the settled pigment. You might need a paint shaker from a hardware store if stirring by hand doesn't work.
- Check Consistency: The paint should return to its original, smooth, liquid consistency. If it remains lumpy or thick even after thorough stirring, it's likely spoiled.
- Strain the Paint: If you managed to get the paint back to a good consistancy, consider straining it before using. This will remove any remaining small lumps.
- Test Patch: Before painting an entire project, apply a small test patch in an inconspicuous area to ensure the paint adheres properly and has the desired color and finish.
-
Why You Shouldn't Use Spoiled Paint:
- Poor Adhesion: Spoiled paint may not adhere properly to surfaces, leading to peeling or flaking.
- Uneven Finish: It can result in an uneven, streaky, or textured finish.
- Color Issues: The color may be altered or inconsistent.
- Health Risks: Some spoiled paints can release harmful gases.
- Clogging: Thick, spoiled paint can clog spray guns and brushes.
-
Proper Disposal: If you determine the paint is spoiled, do not pour it down the drain or into the trash. Check with your local waste management agency for proper disposal guidelines. Many communities have hazardous waste collection programs or designated drop-off locations.
In summary, if the thick paint is simply separated and can be restored to its original consistency with stirring, it may be usable. However, if it shows signs of spoilage, discard it responsibly.
