Red Devil F-Seal 181 Duct Sealant 1 Gallon Water Based HVAC Mastic

SKU: NB841DW

Weight	13 lbs
Dimensions	13 × 12 × 12 in
Condition	New
Manufacturer Part Number	NB841DW
Brand	Red Devil

$30.26

In stock — available to order.

Sold individually. Each quantity ordered is one unit. Kits are one complete kit; products sold by length use the stated length unit.

Same-item volume pricing

Quantity	Unit price	Saving
1–4	$30.26	0%
5–9	$28.75	5%
10+	$27.23	10%

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Red Devil F-Seal 181 Duct Sealant 1 Gallon Water Based HVAC Mastic

Specifications & product details

Red Devil F-Seal® 181 Water-Based HVAC Duct Sealant – 1 Gallon

F-Seal® 181 by Red Devil is a professional-grade, water-based HVAC duct sealant designed for sealing high, medium, and low-pressure duct systems in both indoor and outdoor applications.

This white, brush-on mastic provides excellent coverage, dries quickly, and remains flexible after curing. It is UL 181 A-M and B-M listed, making it suitable for sealing metal and fiberglass ductwork in residential and commercial HVAC systems.

🔧 Key Benefits:

Easy brush-on application
Fast drying, flexible finish
UV resistant for outdoor exposure
Low odor, water-based formula
Helps improve system efficiency & airflow

🏗️ Common Applications:

Supply & Return Duct Sealing
Air Handler & Plenum Connections
New HVAC Installations
Energy Efficiency & Weatherization Projects

F-Seal 181 is trusted by HVAC professionals for durable, code-compliant duct sealing that helps reduce air leakage and improve overall system performance.

⚠️ Apply to clean, dry surfaces. Follow manufacturer cure time recommendations.

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