Old paint cans cluttering your garage? You’re not alone. Many wonder if they can still use that leftover paint or if it’s destined for the hazardous waste bin. This guide provides clear answers about paint expiration, how to spot bad paint, and the risks involved in using it. We’ll also explore ways to potentially revive dried paint and offer tips for safe disposal.
So, Does Paint Expire?
Yes, paint does indeed expire, but its shelf life can vary depending on several factors. The lifespan of paint depends on the type of paint and whether it has been opened:
- Unopened latex paint typically lasts 2-10 years
- Unopened oil-based paint can last up to 15 years
- Opened paint generally lasts 1-2 years if properly sealed and stored
These periods of time relate to either interior paint or exterior paint.
How Can You Tell if Paint Has Gone Bad?
You can tell if paint has gone bad by looking for these signs:
- Odd smell (sour, rancid, or mouldy)
- Chunky consistency that doesn’t smooth out when stirred
- Gel-like texture
- Dried out or solidified
- Significant colour change
- Separated layers that won’t mix back together
- Visible mould or mildew growth
- Rust or corrosion on the paint can
- The colour has faded
What Happens if I Use Old Paint?
Using old paint can lead to several issues, depending on the paint’s condition and how long it has been stored.
Application Issues
- Difficulty spreading evenly
- Streaky or patchy finish
- Poor coverage requiring additional coats
Durability Concerns
- Improper adhesion to surfaces
- Peeling or flaking over time
Aesthetic Problems
- Inconsistent colour
- Visible lumps or texture on the wall
Health and Safety Risks
- Bacterial growth in the paint can lead to persistent odours
- Potential skin, eye, or respiratory irritation
What Are the Health Risks of Using Expired Paint?
Using expired paint can pose several health risks, so it’s generally not recommended. Here are the primary health concerns associated with using old or expired paint:
Bacterial and Mould Growth
Expired paint, especially water-based paints, can become a breeding ground for bacteria and mould. This can lead to:
- Persistent unpleasant odours
- Respiratory irritation
- Allergic reactions
- Potential infections, particularly for those with weakened immune systems
Chemical Degradation
As paint ages, its chemical composition can break down, potentially releasing harmful fumes:
- Volatile Organic Compounds (VOCs) may increase
- Toxic substances might be released during the application
Skin and Eye Irritation
Expired paint may cause:
- Skin rashes or allergic reactions upon contact
- Eye irritation or inflammation
Respiratory Issues
Painters exposed to solvent-based paints face significant respiratory health issues, including breathing problems, prolonged cough, exacerbation of existing respiratory conditions like asthma, and chest discomfort [1].
VOCs such as benzene, toluene, ethylbenzene, and xylene are prevalent in paints and pose both non-carcinogenic and carcinogenic risks [2].
Potential Toxicity
Older paints, especially those from before 1990, may contain hazardous substances:
- Lead-based paints can cause serious health issues if ingested or inhaled as dust
- Mercury, which was sometimes used in paint before 1990, can be toxic
Safety Precautions
If you must use old paint, take these precautions:
- Ensure proper ventilation in your work area
- Wear protective gear, including gloves, goggles, and a respirator
- Test the paint on a small area first to check for any adverse reactions
It’s important to note that while these risks exist, they are generally more pronounced with significantly expired or improperly stored paint. For the safest results and to protect your health, using fresh, high-quality paint for your projects is best.
How To Revive Expired Paint?
While it’s generally not recommended to use expired paint, there are some methods you can try to revive old paint if it’s not too far gone. Here’s how you can attempt to revive expired paint:
Water-Based Paints (Latex)
- Add water gradually to restore consistency
- Stir thoroughly to mix
- Avoid over-thinning by adding small amounts at a time
Oil-Based Paints
- Use paint thinner or mineral spirits
- Add small amounts and stir well
- Aim for the original consistency
General Techniques
- Use paint conditioners or rejuvenators specific to the paint type
- Filter out lumps and impurities with a strainer for smoother texture
- Consider using a paint mixer attachment on a drill for thorough mixing
Before Using Revived Paint
- Test on a small, inconspicuous area
- Check if it spreads evenly and adheres properly
- Observe the dried result for any issues
Important Considerations
- Don’t attempt to revive paint with signs of mould or severe spoilage
- These methods may not work for severely deteriorated paint
- Ensure proper ventilation when working with old paint
Remember, while these techniques can sometimes salvage old paint, it’s often safer and more effective to use fresh paint, especially for large projects or areas requiring a flawless finish.
How Do I Properly Store Paint To Extend Its Shelf Life?
To properly store paint and extend its shelf life, follow these guidelines:
Choose the Right Storage Environment
- Store paint in a cool, dry place with consistent temperature
- Ideal temperature range is between 50°F and 85°F (10°C to 29°C)
- Avoid damp areas like basements or outdoor sheds
- Keep paint away from direct sunlight
Prepare Paint for Storage
- Clean the rim and lid of the paint can to ensure a proper seal
- Mix the paint thoroughly before storage
- Transfer small amounts of leftover paint to smaller containers to minimise air exposure
Seal Containers Properly
- Ensure paint cans are tightly sealed to prevent air from getting in
- Place plastic wrap over the paint can opening before replacing the lid for an extra air-tight seal
- Consider storing cans upside down to create a vacuum seal
Label Paint Cans
- Label each can with the date, room/project used for, and colour code/name
- Include whether it was used for interior or exterior projects
Maintain Stored Paint
- Store paint cans on elevated shelves or pallets to protect from moisture
- Periodically check stored paint for signs of spoilage
- Stir paint thoroughly before use after storage
Additional Tips
- Add paint preservatives before storage to prevent mould and mildew growth
- For water-based paints, avoid freezing temperatures
- Consider climate-controlled storage for optimal preservation
By following these storage techniques, you can significantly extend the shelf life of your paint, keeping it usable for future touch-ups or projects while reducing waste and saving money. If you have any questions about an upcoming paint project don’t hesitate to reach out to the professional painters at Dupaint Sydney.
[1] Pandey, P., & Kiran, U. (2022). Exposure to Paints and Respiratory Health Ailments among Painting Workers in Commercial Sectors. Proceedings of the International Conference on Industrial Engineering and Operations Management. https://doi.org/10.46254/in02.20220454.
[2] Ghobakhloo, S., Khoshakhlagh, A., Morais, S., & Tehrani, A. (2023). Exposure to Volatile Organic Compounds in Paint Production Plants: Levels and Potential Human Health Risks. Toxics, 11. https://doi.org/10.3390/toxics11020111.
