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Pro-grade auto-body supply ยท Any quantity ยท 23,000+ SKUs in stock
23,000+ pro-grade SKUs in stock
US Chemical & Plastics

USC 12-4 Fast Activator, 1 qt Liquid, 4:1 Mix Ratio for Urethane Clearcoat

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$45.60
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Overview

Built for the booth.

A competitively-priced clearcoat that offers body shops a quality finish. With a 4:1 mix ratio, this clearcoat is easy-to apply and ideal for use on spot, panel, multi-panel and overall refinishing.

USCยฎ 12โ€‘4 Fast Activator is a 1โ€‘qt liquid activator formulated for use with US Chemicalโ€™s 10 Universal 4.2โ€ฏVOC urethane clearcoat. It is mixed at a 4โ€ฏparts activator to 10โ€ฏparts clearcoat ratio to initiate rapid crossโ€‘linking, delivering a fast, consistent cure for automotive refinishing applications.

The activator provides a pot life of 2โ€‘4โ€ฏhours at 72โ€ฏยฐF (22โ€ฏยฐC), allowing ample working time while maintaining a quick flash and cure schedule. At a film thickness of 1.0โ€ฏmil it covers approximately 480โ€ฏsqโ€ฏft, making it efficient for large panels. It is compatible with eโ€‘coat and plastic substrates, ensuring reliable adhesion and finish quality on a range of factoryโ€‘prepped surfaces.

Due to its classification as a Warningโ€‘level hazardous material, appropriate personal protective equipmentโ€”including eye protection, gloves, protective clothing, and a respiratorโ€”must be worn. Use in a wellโ€‘ventilated area and follow standard firstโ€‘aid procedures for inhalation, skin, and eye exposure.

Why Pros Choose US Chemical & Plastics Fast

  • A competitively-priced clearcoat that offers body shops a quality finish. With a 4:1 mix ratio, this clearcoat is easy-to apply and ideal for use on spot, panel, multi-panel and overall refinishing.

Application Guide

  1. Clean the substrate (eโ€‘coat or plastic) to remove all contaminants; ensure the surface is dry and free of oil.
  2. Mix USCยฎ 12โ€‘4 Fast Activator with 10 Universal 4.2โ€ฏVOC Urethane Clearcoat at a ratio of 1โ€ฏpart activator to 4โ€ฏparts clearcoat.
  3. Apply the mixed clearcoat using the recommended spray technique; work within the 2โ€“4โ€ฏhour pot life at 72โ€ฏยฐF (22โ€ฏยฐC).
  4. Allow each coat to flash and dry according to the clearcoatโ€™s specifications before applying additional coats.

Compatibility

Compatible paint systems: Urethane, Clearcoat.

Specifications

Technical specifications for USCยฎ 12-4 Fast Activator, 1 qt, Liquid, Use With: 10 Universal 4.2 VOC Urethane Clearcoat
Part No. 12-4
Product Line USC
MFR Model 12-4
Standard/Approvals California Pro65 Warning: Cancer and Reproductive Harm
Manufacturer US Chemical & Plastics
UPC 037307001249
Brand USCยฎ
Maximum Sale Quantity 12
Maximum Sale Day 7
Rubberized No
Color Clear
Container Size (qt) 1
Form Liquid
Type Fast
Mixing Ratio 4:1
Mix Ratio
4 parts 10 clearcoat
Pot Life
2โ€‘4โ€ฏhours @ 72ยฐF / 22ยฐC
Coverage
480โ€ฏsqโ€ฏft @ 1.0โ€ฏmil
Compatible Substrates
eโ€‘coat, plastic

About US Chemical & Plastics

US Chemical & Plastics is a trusted manufacturer of professional auto body and refinish products used by collision repair shops and restoration specialists across North America.

Frequently Asked Questions

What substrates are compatible with USCยฎ 12-4 Fast Activator?

It is formulated for use on eโ€‘coat and plastic substrates.

How much coverage does the activator provide?

One quart covers approximately 480โ€ฏsqโ€ฏft at a 1.0โ€ฏmil film thickness when mixed with the recommended clearcoat.

What personal protective equipment is required when handling this product?

Wear eye protection, chemicalโ€‘resistant gloves, protective clothing, and a respirator suitable for organic vapors.

What is the pot life of the mixed system?

After mixing with the 10โ€ฏUniversal 4.2โ€ฏVOC urethane clearcoat at a 4:1 ratio, the pot life is 2โ€“4โ€ฏhours at 72โ€ฏยฐF (22โ€ฏยฐC).

Documents & Safety

Warning: This activator is toxic if inhaled or swallowed, can cause serious eye injury, skin corrosion, and is flammable. It is also classified as a carcinogen, organ toxin, respiratory irritant, reproductive hazard, and oxidizer. Use eye protection, chemicalโ€‘resistant gloves, protective clothing, and a suitable respirator when handling. Keep the product away from heat, sparks, and open flame. Always refer to the full SDS before use.

Why Buy from autofxmart

  • Authorized distributor โ€” authentic, factory-fresh stock.
  • Fast US shipping โ€” most orders ship within 1 business day.
  • 30-day returns โ€” buy with confidence.
  • Pro-shop pricing โ€” bulk discounts available on request.
  • Expert support โ€” questions? Email us at support@autofxmart.com.
Get the mix right

Mix & coverage calculator

Locked to this product's ratio of 4:1 (clear : hardener).

Clearcoat to spray
5L
Your batch4:1
Clearcoat5
Hardener2.5 L
Ready to spray7.5 L
How to apply

Steps

1Clean and degrease the surface, then scuff as needed.
2Mask off surrounding panels and trim.
3Mix to the product's ratio and strain.
4Apply 2โ€“3 even coats, flashing between each.
5Let cure fully before sanding, buffing, or assembly.
Specifications

Full data

BrandUS Chemical & Plastics
Part #12-4
UPC037307001249
ApplicationA competitively-priced clearcoat that offers body shops a quality fini
Size1
ColorClear
OriginUS
ConditionNew
RubberizedNo
Frequently asked

Good to know

This listing ships US Chemical & Plastics USC in a 1 (QT) container. Check the autofxmart catalog for other sizes and bulk pricing.
US Chemical & Plastics USC uses a mix ratio of 4:1. Always measure activators and reducers accurately to maintain film properties and pot life โ€” deviating from the ratio can cause adhesion or curing problems.
Most in-stock orders for US Chemical & Plastics USC ship the same or next business day from our US warehouse. Expedited options are available at checkout. Freight-class items may require an additional 1โ€“2 days for carrier pickup.
Yes. autofxmart is an authorized distributor of US Chemical & Plastics products. Every unit is factory-fresh, sealed, and backed by the manufacturer's standard warranty. If you have a concern, contact support@autofxmart.com and we will make it right.
The MPN for US Chemical & Plastics USC is 12-4. Use this number when cross-referencing against TDS, SDS, or legacy supplier catalogs.

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