What is Tru Oil and What Makes It Toxic?
Before discussing the finished product's safety, it is essential to understand what Tru Oil actually is. Often mistaken for a simple oil finish like tung oil, Tru Oil is a proprietary blend manufactured by Birchwood Casey, consisting primarily of polymerized linseed oil, modified oils, and petroleum-based solvents, such as mineral spirits. These solvents are the main source of toxicity during the application and curing process.
Toxicity in the Liquid State
During its wet stage, Tru Oil is hazardous. The MSDS explicitly lists several risks associated with direct exposure and inhalation of its vapors:
- Ingestion: Harmful or fatal if swallowed, with risk of lung damage if aspirated during vomiting.
- Inhalation: High concentrations of vapors can irritate the respiratory tract and cause central nervous system effects like dizziness and headaches.
- Skin and Eye Contact: It can cause serious eye irritation and mild skin irritation, potentially leading to redness, itching, and dermatitis with prolonged or repeated exposure.
- Combustibility: The liquid is combustible and requires storage away from sparks and open flames.
Safety of Cured Tru Oil
Once Tru Oil has fully cured, the solvents have evaporated and the polymers have hardened. In this state, the finish is an inert solid and is generally considered safe for human contact. The curing process takes a significant amount of time, often weeks or even months, for the finish to reach its maximum hardness and safety level. For projects like gunstocks, musical instruments, and decorative wood items, the cured finish is durable and poses no significant health risk from handling.
Is Tru Oil Food Safe? The Crucial Distinction
While a fully cured Tru Oil finish is considered safe for incidental contact, it is not certified or recommended as a food-safe finish. This is a critical distinction for woodworkers to understand, especially when considering finishes for items like cutting boards, bowls, or utensils.
Why Tru Oil Isn't Ideal for Food Contact
- Taste and Odor Transfer: Some users report a lingering chemical taste or odor even after the finish has cured for a long time. For items meant for food, this is highly undesirable.
- Solvent Residue: There is a possibility that trace amounts of solvents or their byproducts may remain trapped within the finish, especially if the curing process is not complete. While this might be negligible for decorative items, it is a risk not worth taking for food surfaces.
- Durability and Wear: Tru Oil provides a durable finish for many applications, but it is a film-forming finish that can eventually wear away. If a food surface is regularly used and washed, the finish will degrade, and you risk ingesting small particles of the finish or exposing the food to potentially contaminated wood.
Comparison of Wood Finishes: Tru Oil vs. Food-Safe Alternatives
To highlight the difference, here is a comparison table outlining Tru Oil against truly food-safe options.
| Feature | Tru Oil | Pure Tung Oil (Polymerized) | Mineral Oil / Beeswax Finish |
|---|---|---|---|
| Toxicity (Liquid) | High (contains solvents) | Low (all-natural) | None (Food-grade) |
| Toxicity (Cured) | Generally safe for handling | Non-toxic, food-safe | Non-toxic, food-safe |
| Food Safety | Not recommended | Yes, if 100% pure | Yes, food-grade safe |
| Application | Wiped on, builds layers | Wiped on, penetrates deeply | Wiped on, simple process |
| Curing Time | Weeks to months | Longer than Tru Oil | Instant, but requires reapplication |
| Durability | Hard, protective film | Durable, water-resistant | Low, requires maintenance |
Ensuring Safety During Application
For anyone working with liquid Tru Oil, following proper safety precautions is non-negotiable. These steps protect against exposure to the hazardous components before they cure.
- Ensure Proper Ventilation: Work in a well-ventilated area, preferably outdoors or in a space with powerful local exhaust ventilation. This is crucial for avoiding the inhalation of harmful vapors.
- Use Personal Protective Equipment (PPE): Always wear appropriate PPE, including chemical-resistant gloves (polyvinyl alcohol or natural rubber are recommended) and safety glasses or goggles.
- Protect Your Skin and Eyes: Avoid all skin and eye contact. In case of accidental contact, flush immediately with water and seek medical attention if irritation persists.
- Handle Flammable Materials with Caution: Keep the work area free of sparks, open flames, and other ignition sources, as the liquid is combustible.
- Manage Oily Rags: Rags or cloths soaked with Tru Oil can be prone to spontaneous combustion. After use, immediately immerse them in a water-filled, sealed metal container to prevent fire hazards.
The Final Verdict on Tru Oil Safety
So, is Tru Oil non-toxic? The answer is nuanced. In its liquid form, it is toxic and requires strict safety measures during application. However, once it has fully cured and hardened over time, the finish becomes inert and is generally safe for handling projects like musical instruments and gunstocks. Crucially, due to its composition and potential for lingering solvents, it is not considered safe for food-contact surfaces. For these applications, natural, food-safe alternatives should be used. The ultimate safety of Tru Oil depends entirely on its state (liquid vs. cured) and its intended purpose.
Conclusion
Tru Oil is a powerful and versatile wood finish, prized for its durability and ease of application, particularly for gunstocks and musical instruments. However, its non-toxic status is conditional. Users must respect the hazards of its liquid state by employing proper ventilation and protective gear. While the cured finish is safe for handling, it should not be used on items intended for direct food contact. By understanding this key distinction, woodworkers can use Tru Oil effectively and safely, choosing the right finish for the right project.
