Epoxy resin is a synthetic resin with multiple industrial applications which offers higher thermal, chemical, and mechanical properties than other resins. Epoxy resin is applied in liquid form to a mould or painted in layers over a material to create a protective outer coating. The material becomes durable and structurally stable after curing. This combination of properties makes epoxy resin extremely useful for several applications, including industrial tooling, art projects, and automotive production.

The chemical compounds and polymerization processes that go into epoxy resin will affect its physical properties.

The following are some characteristics of epoxy resin formulas:

  • Strong Adhesive Bond
  • Thermal Resistance
  • Chemically Stable
  • Corrosion-Resistant
  • Electrical Insulation
  • Minimal Moisture Absorption
  • Excellent Flexural and Fatigue Properties
  • Minimal Shrinkage Post-Curing
  • Free Of VOCs (Volatile Organic Compounds)

Co-reactants or hardeners, packaged separately from the epoxy resin, are mixed with the epoxy resin during the application process. A chemical reaction occurs when the two materials are mixed. Depending on the formulation, resins can solidify quickly or slowly. The ratio of epoxy to hardener is specified in the instructions provided with the product to ensure optimum strength and performance.

View the FibreGlassDirect range of Epoxy Resins

Some uses for epoxy resins:

  • Quick repairs, filling and sealing woods & metals
  • Repairing and gluing small parts together
  • Waterproof epoxy sealants for garage, concrete, and cement floors
  • Resin countertops and bar tops
  • Penny Tables & Resin River tables
  • Stabilizing wood with resin 
  • Cutting boards
  • Resin jewellery
  • Resin art paintings & crafts
  • Epoxy moulds and figures of all kinds
  • Decorations
  • Resin shelves for shower trays
  • Resin casting of artefacts and materials in synthetic resin
  • Construction of aquariums & model building
  • Synthetic for boat building & boat repairs

Casting or Coating Epoxy Resins?

There are unique but related compounds used in casting and coating epoxy resins. The choice between the two influences how the end-product looks and functions. 

Casting Epoxy Resin

A casting resin is used to make clear encasings and suspensions. It is also referred to as deep pour resin or pouring plastic. It is poured into a mould and then cured to maintain its shape. Crafts, jewellery, sculptures, and memorabilia are frequently made using casting resins. Casting resin can also manufacture aggregate, moulded plastics, and electrical insulation. Epoxy resin is used to make many products, including automotive parts, aerospace devices, and sports gear.

Coating Epoxy Resin

By contrast, coating resins are aptly named: they are used to coat materials such as metal, concrete, or wood to help them become stronger, chip-resistant, easier to clean, water-resistant, and resistant to rust.

Casting epoxy resin differs from coating epoxy resin in several other notable ways besides application:

  • Casting resins have a thinner viscosity than coating resins.
  • Due to the thick layers of liquid casting resin, it takes longer for them to cure to avoid shrinkage and heat build-up.
  • Resins used for coatings are typically stiffer and more rigid than resins used for casting.
  • Casting resin formulas can vary, such as 2:1, but most coating resins use a 1:1 mix ratio.

Despite significant similarities between both formula types, it's usually easier to use the right formula for your application. Pouring casting resin onto a surface instead of using some thin coating resin will cause the resin to run off the edges and be very slow to harden. Furthermore, if you pour coating epoxy into a mould, you will need to pour multiple thin layers and wait for each layer, as pouring a large amount of resin into a container will accelerate the chemical reaction, which could lead to cracking or yellowing.

Epoxy Resin: What You Need to Know

Consider the following when choosing the most suitable epoxy resin:

  • Will the epoxy resin be used to suspend materials?
  • What mould or frame is needed to prevent dripping and hold the epoxy while it cures?
  • What is the thickness of the epoxy layer needed for this project?
  • What is the cure time for epoxy?
  • How hard should this material be to withstand wear and tear?
  • Do you intend to expose this material to high temperatures, water, chemicals, UV rays, or other potentially damaging elements?
  • What unique properties does the epoxy need to have?
  • What viscosity does the resin need to have?

Epoxy Resin Viscosity

Viscosity measures a fluid's propensity to flow; it relates to the fluid's resistance (liquid or gas) to changes in shape or movement within it. Relative to Epoxy resins the viscosity will determine its ability to drip or spread evenly and whether it should be poured, dipped, or painted over the material. Moreover, the viscosity influences how much epoxy perforates the substrate and what physical properties are produced.

Low Viscosity Resin: 

Low-viscosity epoxy resins are thin and work well for making deep penetrations and filling small gaps. As a result of the consistency, the epoxy adheres to the substrate better, preventing air bubbles. A low-viscosity epoxy resin can be used for potting, sealing, and encapsulation.

Advantages of Low Viscosity Epoxy Resins:

  • Great for Beginners
  • Long shelf life
  • Resistant to mould
  • Can be used on fine cracks
  • Repair and Filling of Concrete Gravity Cracks
  • Overlay of interior surfaces
  • Repairs & Patching
  • Fillers & Sealers
  • Primer for industrial coatings
  • Indoor and outdoor concrete slab crack repair
  • Excellent adhesion
  • Suitable for damp environments
  • Highly penetrating for low surface tension
  • Resistant to shrinkage

Moderate Viscosity Resins

A medium-viscosity epoxy has a thick consistency, and as a result, it is less permeable and more durable than low-viscosity formulations. As well as being able to withstand moderate temperatures, this material is often used for filament winding, vacuum bagging, and tooling.

High Viscosity Resins

High-viscosity epoxy is the most resilient and has a paste-like consistency. It has excellent adhesion, and it is heat and shock resistant. This epoxy is ideal for projects requiring extreme toughness and durability.

How to Use Epoxy Resin Safely?

When using epoxy resin, a variety of safety precautions should be taken.

In the first place, you should wear gloves to protect your hands from resin and hardener liquids. Nitrile gloves are recommended since they are unlikely to react with the skin or resin. If resin does come in contact with the skin, baby wipes can be used to remove resin with any remaining removed with a mixture of soap and water. An exfoliant is a particularly effective option for removal.

It is advisable to wear safety goggles to protect your eyes. In case of contact with the eyes, you should repeatedly flush the eyes with water for 15 minutes without rubbing. Seek medical attention as soon as possible.

A plastic apron or overalls should be worn to protect clothing, allowing any spilt resin to be easily removed. Finally, it is essential to ensure sufficient ventilation by opening windows or using an extractor fan whenever working with epoxy resin. In the event of poor ventilation, you may need to wear a respirator.

What is the Best Epoxy for River Tables?

There is an increasing demand for epoxy resin tables. Epoxy and wood can be combined to produce beautiful tables in all shapes and sizes. However, the process itself takes some practice. Depending on the table's size, it takes over 10kg of resin or more to cast a tabletop of 5cm thickness.

The thickness of this layer is also critical. The casting resin must be specifically formulated for this application to provide such a thick layer after one pour.

The exothermic reaction caused by a commercially available, inexpensive resin can cause a lot of heat and damage to the wood and the surrounding area. For this reason, patience is a virtue, and several thin layers must be poured on top of each other, which must dry for several hours to work.

The following properties are particularly relevant to epoxy resin tables:

  • A layer height of up to 5cm should be achievable, and the resin must be processable in large quantities without overheating
  • We recommend a longer pot life to allow air bubbles to escape more efficiently as well as UV protection to prevent yellowing.

Suitable for resin river tables, penny floors and bar tops, TriCast Epoxy Clear Cast Resin is an advanced, hard-wearing resin. The resin is fast curing and leaves a tack-free finish, and it doesn't require any additional sanding or compounding once it has cured.

Multiply the height (in metres) by the width (in metres) by the depth (in millimetres) to determine the volume of resin needed.

For example, to cover a table, 1-meter-high x 2 meters wide x 5 mm deep = 10litres/kg resin.