Novol 35824 Protect Hardener H5520 (700ml) – The "Standard" Activator for Novol Fillers
The Novol H5520 is the versatile, "Standard" speed hardener designed to activate the wide range of Novol 2K acrylic fillers. This 700ml unit is the essential chemical partner for the Protect 300, 310, 330, and 350 series, ensuring a consistent cure and a stable foundation for your topcoat.
Formulated for optimal performance at room temperature (approx. 20°C), the H5520 offers a balanced working time that allows for smooth application without the product "flashing" too quickly in the spray gun.
System Compatibility & Mixing
This hardener is specifically matched to the 5:1 and 4:1 ratios found in the Novol Protect filler range.
- The "Perfect Pair": This 700ml bottle is exactly measured to pair with a 3.5 Litre tin of Protect 330 (37333) to achieve the required 5:1 mixing ratio.
- Mixing Ratios (Check your Filler TDS):
- 5:1 System: 5 parts Filler to 1 part Hardener.
- 4:1 System: 4 parts Filler to 1 part Hardener.
- Pot Life: Once mixed at 20°C, you have approximately 45–60 minutes of usable spraying time.
Key Features & Benefits
- Universal Versatility: One hardener covers multiple filler types (300, 310, 330, 350), simplifying your workshop inventory.
- Optimal Flow: Works with the filler resins to provide a smooth, level finish that reduces the amount of block-sanding required.
- Standard Curing Speed: Ideal for general workshop conditions, providing a predictable dry-to-sand time of 3 hours at 20°C.
- Anti-Shrink Stability: Ensures the acrylic filler reaches full chemical cross-linking, preventing "sandpaper marks" from reappearing weeks after painting.
- Easy Sanding: Contributes to a crisp, dry-sanding surface that won't clog fine-grit abrasives like P400 or P500.
Professional Mixing Strategy
Hardeners are highly reactive. To ensure your primer cures perfectly:
- Seal the Cap: Isocyanates in the hardener react with moisture in the air. Always wipe the rim and tighten the cap immediately after use to prevent "skinning."
- Stirring: Pour the filler first, add the H5520 Hardener, and stir thoroughly for 60 seconds before adding any thinner.
- Thinning: Once activated, you can adjust viscosity with Novol Thin 850 (approx. 10–20%) depending on whether you want a high-build filler or a primer-surfacer.
- Temperature Tip: If your shop is below 15°C, consider using the "Fast" version (H5521); if above 30°C, the "Slow" version is recommended to avoid "dry spray."
