PUR Black NF - Black Straw Foam 16oz

PUR Black NF is a black expanding foam specifically designed for pond and waterfall construction. This 16-ounce self-dispensing can with attached straw makes it easy to fill voids between rocks, direct water flow, and create natural-looking waterfall effects—no foam gun required. The black color blends seamlessly with rocks and disappears in shadows for a professional, natural appearance.

Key Features:

• Black color blends naturally with rocks and stone
• Self-dispensing can with attached straw—no foam gun needed
• Perfect for DIY pond and waterfall projects
• Fills voids and gaps between rocks
• Directs and optimizes water flow over waterfalls
• Expands to fill irregular spaces
• 16-ounce can for single-use applications
• Easy to use for beginners and professionals

Why Black Foam for Ponds:

• Natural Appearance: Black color disappears in shadows and blends with wet rocks
• Professional Results: Looks far better than tan or yellow foam in water features
• Hides Imperfections: Dark color conceals foam in crevices and behind rocks
• Water Feature Specific: Designed for pond and waterfall construction

Common Uses:

• Filling voids between waterfall rocks to direct water flow
• Sealing gaps to prevent water from disappearing behind rocks
• Creating water channels and directing spillways
• Building up areas to optimize water sheet flow
• Securing rocks in place during waterfall construction
• Filling spaces around skimmers and plumbing
• Creating natural-looking rock formations

How to Use:

1. Shake can vigorously for 30 seconds before use
2. Attach included straw to dispensing valve
3. Hold can upside down during application
4. Insert straw into void or gap between rocks
5. Dispense foam in short bursts—foam will expand 2-3 times
6. Allow foam to cure (typically 24 hours for full cure)
7. Trim excess foam with knife if needed
8. Cover exposed foam with rocks or gravel for natural appearance

Application Tips:

• Use less foam than you think—it expands significantly
• Fill voids in layers for deep gaps, allowing each layer to cure
• Keep rocks wet during application for better adhesion
• Work from bottom to top when building waterfalls
• Use foam sparingly—you can always add more
• Clean straw immediately after use to prevent clogging

Self-Dispensing Convenience:

• No expensive foam gun required
• Perfect for small projects or occasional use
• Attached straw provides precise application
• Ideal for DIY homeowners and first-time pond builders
• Single-use can—use entire can once opened

Specifications:

• Size: 16 ounces
• Color: Black
• Type: Single-component expanding polyurethane foam
• Application: Self-dispensing with attached straw
• Expansion: Approximately 2-3 times original volume
• Cure time: Tack-free in 30-60 minutes, full cure in 24 hours
• Use: Pond and waterfall construction

What's Included:

• 1 can of PUR Black NF expanding foam (16 oz)
• Attached dispensing straw

Coverage:

• Coverage varies based on void size and foam expansion
• 16 oz can is suitable for small to medium projects
• For large waterfall projects, multiple cans may be needed

Important Notes:

• Use entire can once opened—foam will cure in can if stored
• Work in well-ventilated area
• Wear gloves—uncured foam is difficult to remove from skin
• Foam is permanent once cured
• Not paintable—black color is permanent
• For fish safety, allow foam to fully cure before filling pond with water

Note: This is a single-use, self-dispensing foam can with attached straw—perfect for DIY projects and occasional use. For professional contractors or large projects requiring multiple cans, consider professional foam gun systems with refillable cans for better economy and control. Once opened, use the entire can as foam will cure inside if stored.

Frequently Asked Questions

Q: Why should I use black foam instead of regular tan or yellow foam for my pond?
A: Black foam is specifically designed for water features because it blends naturally with the environment. In ponds and waterfalls, rocks are often wet and appear dark, and shadows are common in crevices and behind rocks. Black foam disappears in these conditions, creating a natural appearance. Regular tan or yellow foam stands out like a sore thumb in water features—it's highly visible and looks artificial. Even small amounts of exposed foam can ruin the natural aesthetic you're trying to create. Black foam gives you professional-looking results and is worth the small additional cost for the dramatic improvement in appearance.

Q: How much foam should I use, and how much will it expand?
A: PUR Black foam expands approximately 2-3 times its original dispensed volume, so use less than you think you need. Start with small amounts—you can always add more, but you can't remove cured foam easily. For a gap that's 2 inches wide, dispense only about ¾ inch of foam and let it expand to fill the space. Dispense foam in short bursts rather than continuous streams. For deep voids (more than 6 inches), fill in layers, allowing each layer to cure before adding the next. Over-foaming is a common beginner mistake that wastes product and creates messy cleanup.

Q: Is this foam safe for fish, and when can I add water after using it?
A: Once fully cured, PUR Black foam is inert and safe for fish and aquatic life. However, you must allow the foam to cure completely before filling your pond with water or adding fish. The curing process releases gases that could be harmful to fish. Allow at least 24-48 hours for full cure before introducing water. You'll know the foam is cured when it's firm to the touch and no longer tacky. For best results, cure for 48 hours, then rinse the foamed areas thoroughly before filling the pond. The black color is permanent and won't leach into the water.