---
product_id: 1871292
title: "Smooth-Cast Onyx Fast - Ultra-Black Urethane Casting Resin - Pint Unit"
brand: "smooth-on"
price: "$98.21"
currency: USD
in_stock: true
category: "Smooth On"
url: https://www.desertcart.us/products/1871292-smooth-cast-onyx-fast-ultra-black-urethane-casting-resin-pint
store_origin: US
region: United States of America
---

# Ultra-fast 10-15 min cure Deep, rich black finish Easy 1:1 mix ratio Smooth-Cast Onyx Fast - Ultra-Black Urethane Casting Resin - Pint Unit

**Brand:** smooth-on
**Price:** $98.21
**Availability:** ✅ In Stock

## Summary

> 🖤 Cast fast, cast flawless—own the black magic of molding!

## Quick Answers

- **What is this?** Smooth-Cast Onyx Fast - Ultra-Black Urethane Casting Resin - Pint Unit by smooth-on
- **How much does it cost?** $98.21 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/1871292-smooth-cast-onyx-fast-ultra-black-urethane-casting-resin-pint)

## Best For

- smooth-on enthusiasts

## Why This Product

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

## Key Features

- • **Effortless 1:1 mixing:** Simplify your workflow with a perfect volume ratio and low viscosity for smooth pouring.
- • **Lightning-fast curing:** Get from mix to mold in just 15 minutes—no downtime, all playtime.
- • **Durable & heat resistant:** Hard Shore 80D hardness ensures your castings withstand the test of time and temperature.
- • **Non-toxic & user-friendly:** Safe for your creative space with mercury-free, adult-friendly formulation.
- • **Striking ultra-black finish:** Achieve a sleek, professional look that stands out in any project or portfolio.

## Overview

Smooth-Cast Onyx Fast is a mercury-free urethane resin designed for rapid room-temperature curing into a deep black, solid plastic. Featuring a user-friendly 1:1 mix ratio and low viscosity, it enables quick, precise pours with a working time of 2.5 minutes and full demold in 10-15 minutes. With a Shore hardness of 80D, it delivers superior durability and heat resistance, making it ideal for professional-grade model casting and sculpting projects.

## Description

Shop Smooth-On at the desertcart Arts, Crafts & Sewing store. Free Shipping on eligible items. Save on everyday low prices.

## Features

- PRODUCT PURPOSE: Smooth-Cast ONYX is a mercury-free urethane resin that cures quickly at room temperature to a deep black, solid plastic
- KEY SPECIFICATIONS: mix ratio and has a very low viscosity, so it is easy t, working time 2, cure or demold 10-15 mins, hardness 80D
- VERSATILE APPLICATIONS: POT LIFE: 2.5 mins
- WORKABLE PROCESS: ONYX offers the convenience of a 1A:1B by volume mix ratio and has a very low viscosity, so it is easy to mix and pour
- FINISHED PERFORMANCE: , SHORE HARDNESS: 80D and offers higher physical properties and higher heat resistance vs

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B00IMIEP8K |
| Age Range Description | Adult |
| Best Sellers Rank | #130,239 in Arts, Crafts & Sewing ( See Top 100 in Arts, Crafts & Sewing ) #940 in Sculpture Molding & Casting Products |
| Brand Name | Smooth-On |
| Color | Black |
| Customer Reviews | 4.6 4.6 out of 5 stars (324) |
| Educational Objective | Creative Skill |
| Included Components | Sculpting Tool |
| Item Dimensions | 5.9 x 3.1 x 7.7 inches |
| Item Weight | 1 kg |
| Manufacturer | Smooth-On, Inc. |
| Manufacturer Part Number | SmoothCastOnyxFast |
| Material Type | Plastic |
| Model Name | Smooth-Cast Onyx Fast |
| Model Number | 4336899307 |
| Number of Items | 1 |
| Other Special Features of the Product | Non-Toxic |
| Recommended Uses For Product | Model Casting |
| UPC | 751635403413 |
| Unit Count | 1 Count |

## Product Details

- **Age Range (Description):** Adult
- **Brand:** Smooth-On
- **Color:** Black
- **Educational Objective:** Creative Skill
- **Included Components:** Sculpting Tool
- **Item Weight:** 1 kg
- **Material:** Plastic
- **Number of Items:** 1
- **Recommended Uses For Product:** Model Casting
- **Special Feature:** Non-Toxic

## Images

![Smooth-Cast Onyx Fast - Ultra-Black Urethane Casting Resin - Pint Unit - Image 1](https://m.media-amazon.com/images/I/718dd+OVBjL.jpg)

## Available Options

This product comes in different **Size** options.

## Frequently Bought Together

- Smooth-Cast Onyx Fast - Ultra-Black Urethane Resin - Pint Unit
- Mold Star 15 Slow - 1A:1B Mix by Volume Platinum Silicone Rubber - Pint Unit
- Smooth-Cast™ 300: Bright White, Low Viscosity, Liquid Plastic Casting Resin - Pint Unit

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**Shop now:** [https://www.desertcart.us/products/1871292-smooth-cast-onyx-fast-ultra-black-urethane-casting-resin-pint](https://www.desertcart.us/products/1871292-smooth-cast-onyx-fast-ultra-black-urethane-casting-resin-pint)

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*Product available on Desertcart United States of America*
*Store origin: US*
*Last updated: 2026-08-27*