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What kind of paint is Herculiner?

Herculiner is a popular do-it-yourself truck bed liner that provides a durable, protective coating to prevent damage to truck beds. But what exactly is Herculiner made of? Let’s take a closer look at the composition and properties of this unique coating.

Introducing Herculiner

Herculiner is a polyurethane-based coating that is designed to protect truck beds from wear and tear. It was first introduced in the early 1990s by Herculiner, Inc. as an affordable DIY alternative to professional spray-on bed liners. Since then, it has become one of the most popular truck bed liners on the market.

Herculiner comes in a two-part kit that contains a pigmented polyurethane resin and a catalyst. To apply it, you simply mix the two components together per the instructions and roll it onto your truck bed using the included roller. As it cures, it forms a thick, textured coating that adheres tightly to the truck bed.

Polyurethane Composition

The key to understanding what makes Herculiner so durable and protective is its polyurethane composition. Polyurethanes are polymers derived from reactions between polyols and diisocyanates. In the case of Herculiner, the specific chemistry includes:

  • Aromatic diisocyanates: Provide hardness and durability
  • Polyether and polyester polyols: Give flexibility and impact resistance
  • Pigments: Supply color and hide imperfections
  • Catalysts and additives: Control curing speed and modify properties

When these ingredients react, they form tough, rigid crosslinks and molecular chains. This is what gives cured Herculiner its hardness and abrasion resistance.

Performance Properties

Thanks to its specialized polyurethane formulation, Herculiner has excellent performance properties that make it ideal for protecting truck beds:

Property Performance
Hardness 85 Shore D hardness provides scratch resistance
Adhesion Bonds tightly to properly prepared surfaces
Abrasion Resistance Resists scuffing and abrasion from cargo
Flexibility Does not crack or peel from bed movement
Impact Resistance Absorbs shock without damage
Chemical Resistance Stands up to most chemicals and road salts
UV Resistance Minimal fading or chalking from sun exposure

These traits make Herculiner an ideal protective coating for truck beds and other automotive applications.

Herculiner Curing Process

One of the keys to getting great results with Herculiner is understanding its curing process. Here are the basic steps:

  1. Mix resin and catalyst – The isocyanate groups in the resin react with the catalyst to start curing
  2. Apply to surface – The liquid coating wets out and adheres to the truck bed
  3. Moisture cure – Atmospheric moisture triggers the curing reaction to accelerate
  4. Crosslinking occurs – Isocyanate groups bond with polyols and each other to cure and harden
  5. Full cure – Coating reaches complete cure in 5-7 days

During this process, Herculiner goes from a thick liquid to a hard, protective plastic coating. Understanding these steps helps ensure proper application and cure.

Herculiner Roll On Application

Applying Herculiner properly is essential to getting great results. Here is an overview of the roll on application process:

  1. Surface Prep – Clean and scuff truck bed so coating can adhere
  2. Mixing – Thoroughly mix resin and catalyst as directed
  3. Rolling – Use included roller to apply 2-3 even coats
  4. Texturing – While still wet, use included brush to add texture
  5. Curing – Allow 5-7 days for full cure
  6. Recoating – Apply additional coats as needed for repairs or touch ups

Following these steps helps ensure you get a thick, protective coating that fully cures. Rushing the job or skipping steps can lead to failure or underperformance.

Herculiner Professional Spray On Application

While the standard Herculiner kit is designed for roll-on application, the company also offers a professional spray grade version. This allows for professional-quality application using an airless paint sprayer. Here is an overview:

  • Surface is prepped in the same manner as the roll-on process
  • Special spray gun and compressor is used to apply the coating
  • Professional grade resin has lower viscosity for spraying
  • Allows for thicker, uniform coats in less time
  • Produces a smoother, more consistent finish
  • Still requires 5-7 days of curing time

For DIY enthusiasts the roll-on kit works well, but for fleet or commercial applications the professional spray grade allows for quicker, higher quality jobs.

Typical Herculiner Coating Thickness

One of the key factors in getting maximum protection from Herculiner is achieving sufficient coating thickness. Here are the typical wet and dry film thicknesses to expect:

Coats Wet Thickness Dry Thickness
1 coat 16 mils 12 mils
2 coats 32 mils 24 mils
3 coats 48 mils 36 mils

Most DIY applications use 2-3 coats. The product data sheet recommends a minimum dry thickness of 20 mils for proper protection. Applying multiple coats ensures you achieve this protective thickness once cured.

Herculiner Skid Resistance

In addition to protection, Herculiner also provides excellent skid resistance thanks to its thick, textured finish. Skid resistance is important for securing cargo and providing traction inside the truck bed.

Herculiner achieves its skid resistance through:

  • Textured finish – Provides grip and traction
  • Gritty surface – Created by embedded aggregates
  • Thick coating – Prevents metal-on-metal contact
  • Stiff formulation – Does not become slippery when wet

Tests have shown Herculiner can provide a coefficient of friction over 0.6, comparable to professional spray-on bed liners. This high level of skid resistance prevents tools, cargo, and other items from sliding around in the bed.

Common Applications for Herculiner

While truck beds are the most common use for Herculiner, its durable polyurethane formulation makes it suitable for a variety of applications including:

Application Benefits
Truck beds Protects against dents, rust, scratches
Trailers Provides skid resistance and impact protection
Boat decks Slip resistant and waterproof coating
Ramps Grippy texture prevents slips and falls
Floors Durable and chemical resistant
Equipment Great for ATVs, tractors, implements, etc.

Herculiner bonds well to wood, metal, fiberglass and other common materials, allowing it to protect and add traction to a wide variety of surfaces.

Herculiner Roll On vs. Spray On

When deciding which Herculiner product to use, consider these differences between the roll on and spray on options:

Roll On Kit Spray On
Method Rolled on with brush Sprayed with professional equipment
DIY friendly Easy for home use Requires professional sprayer
Speed Slower application Much faster coverage
Finish More pronounced texture Smoother, more uniform finish
Performance Slightly thinner coats Thicker coverage possible
Cost More affordable Higher material and equipment costs

For most DIY applications, the roll on kit provides great results at a reasonable price. Professional installers may benefit from the spray on product.

Herculiner Reviews

With decades on the market, Herculiner has been tested by countless truck owners. Here are some common thoughts from Herculiner reviews:

  • Provides excellent protection from dents, rust, scratches
  • Easy to apply roll-on kit for DIY use
  • Provides a thick, durable coating when applied properly
  • Not the most attractive finish for show trucks
  • Can be prone to peeling if surface isn’t properly prepped
  • Textured finish can make sliding items in/out difficult
  • Notable odor during application requires good ventilation

Overall, reviews indicate Herculiner performs well when applied properly to a properly prepared surface. Taking the time to correctly prep and coat the truck bed leads to great results.

Herculiner vs. Other Top Coatings

Herculiner is one of the most popular DIY truck bed liners but faces stiff competition from other top brands. Here’s how some other leading options compare:

Brand Type Key Features
Herculiner Polyurethane Thick protective coating, textured for traction, popular roll-on application
Rust-Oleum Epoxy/Urethane Good value, multiple finish options, less messy than Herculiner
Line-X Polyurea Professional spray-on installation, rigid high density, smooth/textured options
Rhino Liner Polyurethane Softer formulation, professional spray-on, textured matte black finish

Herculiner is a great choice but these competitors also offer quality DIY and professional alternatives depending on your needs and preferences.

Is Herculiner Worth It?

Given its strong reputation, Herculiner is worth considering if you need to protect your truck bed or another surface from wear. The main advantages of using Herculiner include:

  • Affordable DIY kit for home use
  • Thick, durable polyurethane coating
  • Excellent adhesion and abrasion resistance
  • Textured finish provides good skid resistance
  • Easy to touch up and recoat over time

Just keep in mind proper surface prep and application technique is crucial to getting great results. Taking the time to correctly roll or spray on multiple coats ensures maximum protection and durability.


Herculiner polyurethane truck bed liner has remained a popular choice for over 25 years thanks to its protective performance, textured finish, and simple roll-on application. Its unique formulation provides a thick, durable coating that protects against dents, rust, abrasion, and other damage. While professional spray-on options exist, the Herculiner roll-on kit provides a budget-friendly DIY solution for coating truck beds and other surfaces when applied properly. If you’re looking to coat and protect your truck bed from the rigors of work and play, Herculiner remains a top option to consider.