Waterlox, a popular tung oil-based finish known for its durability and water resistance, presents a unique challenge when considering its application: the container. While many woodworkers swear by metal cans, the question of using a plastic cup for Waterlox arises, especially for smaller projects or touch-ups. This article delves into the complexities of using a plastic cup for Waterlox, exploring its pros, cons, and best practices.
The Chemistry Conundrum: Waterlox and Plastics
The key lies in understanding Waterlox's composition. It's not just a simple oil; it's a complex mixture including tung oil, solvents, and potentially other additives depending on the specific formula (Original, Satin, etc.). These solvents can react differently with various plastics. Some plastics might be completely unaffected, while others could be degraded, warped, or even dissolved, leading to a messy situation and potentially contaminating your finish.
Identifying Compatible Plastics
Unfortunately, there's no simple "yes" or "no" answer. Determining compatibility requires knowing the specific type of plastic. Look for a recycling symbol on the cup with a number inside (e.g., #1 PET, #2 HDPE, #5 PP). Polypropylene (#5 PP) is generally considered more resistant to solvents than other types of plastics. However, even with PP, prolonged exposure or high concentrations of solvents in Waterlox could still cause degradation over time.
Important Note: Even if the plastic seems resistant initially, it's crucial to test a small amount of Waterlox in an inconspicuous area of the cup before committing to using it for your entire project. Observe for any signs of warping, softening, or discoloration.
Practical Considerations: Pros and Cons
Using a plastic cup for Waterlox presents a trade-off between convenience and potential risks.
Advantages:
- Convenience: Disposable plastic cups are readily available and easily discarded after use, minimizing cleanup. This is particularly beneficial for small projects or touch-ups where cleaning a metal can might seem excessive.
- Cost-effectiveness: Plastic cups are significantly cheaper than dedicated metal containers for Waterlox.
Disadvantages:
- Chemical Compatibility: The risk of plastic degradation remains the most significant drawback. A compromised cup could release plastic particles into your finish, affect the curing process, or simply create a messy cleanup.
- Disposal: While convenient, ensure responsible disposal of the used cup. Do not simply throw it in regular household waste; check your local guidelines for proper disposal of solvent-contaminated materials.
- Potential for Odor Absorption: Some plastics might absorb the odor of Waterlox, leaving a lingering smell even after the cup is cleaned.
Best Practices for Using Plastic Cups with Waterlox
If you decide to use a plastic cup, take these precautions to minimize risks:
- Choose Polypropylene (#5 PP): Opt for polypropylene cups whenever possible. They're generally more solvent-resistant.
- Perform a Test: Always test a small amount of Waterlox on the cup before using it for the main project.
- Short-Term Use: Use the plastic cup only for immediate application. Don't store Waterlox in a plastic cup for extended periods.
- Thorough Cleaning (If Reusable): If you're tempted to reuse the cup, clean it immediately and thoroughly with a suitable solvent (check the Waterlox manufacturer's recommendations) and ensure it's completely dry before storing.
- Avoid Heat: Don't expose the cup and Waterlox to excessive heat, which could accelerate any potential chemical reactions.
Conclusion: Weighing the Risks
While using a plastic cup for Waterlox might seem convenient, the potential risks associated with chemical incompatibility must be carefully considered. The best approach is often using a metal container specifically designed for finishes. However, if you must use a plastic cup, follow the best practices outlined above and prioritize safety and responsible disposal. Prioritizing the longevity and quality of your finish should always outweigh the minor cost and convenience of using a plastic cup.
