---
product_id: 14093112
title: "Hardcast 304156 1 Gallon Duct Seal 321 Water Based Duct Sealant"
brand: "hardcast"
price: "R1721"
currency: ZAR
in_stock: true
reviews_count: 6
category: "Hardcast"
url: https://www.desertcart.co.za/products/14093112-hardcast-304156-1-gallon-duct-seal-321-water-based-duct
store_origin: ZA
region: South Africa
---

# Quick-setting liquid form Compact 1-gallon size Silicone-based durability Hardcast 304156 1 Gallon Duct Seal 321 Water Based Duct Sealant

**Brand:** hardcast
**Price:** R1721
**Availability:** ✅ In Stock

## Summary

> 🛠️ Seal the deal with Hardcast—where precision meets power!

## Quick Answers

- **What is this?** Hardcast 304156 1 Gallon Duct Seal 321 Water Based Duct Sealant by hardcast
- **How much does it cost?** R1721 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.co.za](https://www.desertcart.co.za/products/14093112-hardcast-304156-1-gallon-duct-seal-321-water-based-duct)

## Best For

- hardcast enthusiasts

## Why This Product

- Trusted hardcast brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Effortless Application Liquid:** Smooth liquid form ensures quick, precise sealing with minimal mess.
- • **Perfectly Portable 1-Gallon Size:** Compact and manageable, ideal for professional use without bulk or waste.
- • **Trusted by Pros, Loved by Reviews:** Highly rated for flawless performance—join the community of HVAC experts who rely on Hardcast.
- • **Silicone Strength for Lasting Seals:** Engineered with premium silicone for superior adhesion and flexibility in HVAC applications.
- • **Specialized for Air Duct Excellence:** Designed specifically for heating and ventilation systems to maintain airtight efficiency.

## Overview

Hardcast 304156 is a 1-gallon, silicone-based duct sealant designed for HVAC professionals seeking a reliable, easy-to-apply solution. Its compact liquid form ensures quick setting and strong adhesion, making it the go-to choice for airtight, durable duct sealing.

## Description

DS-321-GRAY-4-1 GAL

Review: Best stuff - Works perfectly
Review: Cool - 👍

## Features

- DS-321-GRAY-4-1 GAL

## Technical Specifications

| Specification | Value |
|---------------|-------|
| Brand | Hardcast |
| Item Form | Liquid |
| Item Weight | 4.8 Kilograms |
| Material | Silicone |
| Style | Compact |
| Water Resistance Level | Not Water Resistant |

## Product Details

- **Material:** Silicone
- **Brand:** Hardcast
- **Style:** Compact
- **Water Resistance Level:** Not Water Resistant
- **Item Form:** Liquid

## Images

![Hardcast 304156 1 Gallon Duct Seal 321 Water Based Duct Sealant - Image 1](https://m.media-amazon.com/images/I/31EaMwdWSXL.jpg)

## Customer Reviews

### ⭐⭐⭐⭐⭐ Best stuff
*by J***N on July 23, 2025*

Works perfectly

### ⭐⭐⭐⭐ Cool
*by S***F on September 1, 2025*

👍

### ⭐⭐⭐⭐⭐ Great stuff
*by S***G on September 3, 2021*

I needed this to seal some rooftop duct work it worked just as good now as it did 20 years ago when I was doing HVAC. it was listed at a fair price

## Frequently Bought Together

- Hardcast 304156 1 Gallon Duct Seal 321 Water Based Duct Sealant
- Rolled Mastic Duct Sealants Foils 3'' X100

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**Shop now:** [https://www.desertcart.co.za/products/14093112-hardcast-304156-1-gallon-duct-seal-321-water-based-duct](https://www.desertcart.co.za/products/14093112-hardcast-304156-1-gallon-duct-seal-321-water-based-duct)

---

*Product available on Desertcart South Africa*
*Store origin: ZA*
*Last updated: 2026-01-23*