Novol N99423 Ultra Klarlack Harter – Hardener for Klarlack 300/400, 500ml
The Novol N99423 Ultra Hardener is a professional-grade activator designed specifically for use with the Ultra Klarlack 300 and Ultra Klarlack 400 acrylic clearcoat systems. This 500ml unit is the essential chemical catalyst required to transform the liquid clearcoat into a durable, high-gloss, and weather-resistant protective finish.
Formulated for a precise 2:1 mixing ratio, this hardener ensures that the clearcoat reaches its full structural hardness and chemical stability at standard workshop temperatures.
Key Features & Benefits
- Universal Compatibility: Specifically engineered to cross-link with the resins in both Ultra 300 and Ultra 400 clearcoats, ensuring a reliable and predictable cure every time.
- High Gloss Stability: Supports the clearcoat in maintaining its "mirror" finish throughout the drying process, preventing "die-back" or hazing as the solvents evaporate.
- Non-Yellowing Formula: Contains high-purity components that ensure the clearcoat remains crystal clear, preserving the true color of the basecoat underneath.
- Optimal 2:1 Ratio: This 500ml bottle is perfectly measured to activate a 1.0-litre tin of Klarlack, creating a total of 1.5 litres of ready-to-spray material.
- Balanced Curing Speed: Designed as a "Standard" speed hardener, it provides a comfortable "open time" for the clearcoat to flow and level out, which is critical for achieving a smooth finish on larger panels.
- Weather & Chemical Resistance: Once fully cured, it enhances the clearcoat’s ability to resist UV radiation, road salt, and fuel spills.
Professional Mixing & Handling
- The 2:1 Rule: Use a Novol 2:1 Measuring Stick or a graduated mixing cup. Acrylic systems are chemically precise; an incorrect ratio (too much or too little hardener) will lead to a finish that either never fully hardens or becomes prone to cracking.
- Stirring: After adding the N99423 to the clearcoat, stir thoroughly for at least 60 seconds, ensuring you reach the bottom and corners of the mixing container.
- Nozzle Selection: When using this mix with Ultra 400, a 1.3mm – 1.4mm gravity-fed spray gun is recommended for the best atomization.
- Airtight Storage: Hardener is highly sensitive to humidity. Always replace the cap immediately after pouring. If the liquid becomes cloudy or "chunky" in the bottle, it has reacted with moisture and should not be used.
Why Choose the Ultra 400 Hardener?
While some "universal" hardeners exist, using the dedicated Novol N99423 ensures that the chemical bond is exactly as the laboratory intended. It provides the perfect balance of "flow" and "fix," giving you enough time to walk around a car and finish a roof without the clearcoat drying too quickly and leaving a "dry spray" edge.
