The Basics of Resin Casting in Woodworking

The Basics 

Resin is a material that works well for a variety of woodworking applications. Popular results of utilizing resin in woodworking projects include lamps impregnated with resin, jewelry boxes, river tables, and encasements. Encasements with wood combine to create lovely ornamental components. To give the sculpture more depth and character, colored resins can be used to fill in the fractures. An epoxy river that runs through the center of a hardwood slab is what creates river tables. In addition to creating a gorgeous visual display, this may be utilized to showcase accessories like jewelry and miniatures. You may choose softer woods like walnut or cherry, or more common hardwoods like oak for jewelry boxes.

While sealing and safeguarding any jewelry items stored inside, the resin produces eye-catching visual effects. Last but not least, resin-infused lamps are growing in popularity among woodworkers. Recent trends involve combining a variety of elements into the designs, including plants, pebbles, shells, and more. This gives the light a captivating and distinctive appearance.

What is resin casting?

In the standard industrial process of casting, liquid material, typically heated beforehand, is poured into a mold cavity. The liquid substance solidifies to form a new item in the mold’s shape as it cools. After being formed, the freshly formed item—called a casting—is taken out of the mold and either packaged and sold as a finished good or utilized for further manufacturing procedures. On the other hand, resin casting is a distinct casting technique distinguished by the use of synthetic resin.

Resin casting, as the name implies, is a casting technique that uses synthetic resin. You must first examine the synthetic resin utilized in this casting technique in order to have a better understanding of how it functions. Any kind of resin that cures to form stiff, strong polymers is known as synthetic resin. Put another way, it starts off liquid and, when cured, turns into a solid form.

Liquid synthetic resin and curing agent are combined in resin casting, usually at room temperature or slightly below. The two materials are then added to a mold cavity. The resin is subsequently effectively hardened by the curing agent, which changes it into stiff polymers. The hardened casting is extracted from the mold chamber and discharged after this chemical reaction is complete.

Types of resins used in woodworking

Resins are colorless, viscous materials made of two chemicals together. The two components must be combined exactly as directed in order to create wood epoxy resin, which is then poured into the appropriate mold to take on the required shape. Plant-based resins have long been used by humans to manufacture varnishes, fragrances, and other cosmetics. As a result, resins are now widely utilized and useful.

Epoxy Resin

Epoxy resin is a two-part resin system that is robust and frequently used for surface adhesion and sealing. Because of its exceptional strength, filling capabilities, and water resistance, it is frequently used as a bonding agent. Moreover, it may be used to waterproof wood for uses like lathe-turned wood and boat building.

Epoxy resin is a multipurpose resin with a wide range of uses and benefits. This makes it the best option for a lot of projects:

Epoxy resin is designed to be used as an adhesive for joining materials, including glass, stone, metal, concrete, and wood. However, its adhesive ability becomes weaker at temperatures exceeding 177 °F.

Epoxy resin can also be used as a surface coating to improve resistance to abrasion, solvents, and water. A little layer of epoxy coating can make flooring become glossy, smooth, and less brittle, or it can shield ships from corrosion and water absorption.

Epoxy resin is used to create molds, castings, furniture, and aviation parts because of its strong bond and light weight. Because of its insulating qualities, it is also often used in the fabrication of electrical industry products, including printed circuit boards, motors, generators, and insulating coverings.

Resin artwork, jewelry, and ornamental pieces may be made using epoxy resin due to its ability to generate glossy coats and crystal-clear surfaces.

Polyester Resin

With its great adherence to wood, clear finish, affordability, and ease of application, polyester resin is a popular choice for woodworking tasks. It performs better financially than most other varieties when producing huge quantities of intricate molds. It is most frequently used on outdoor furniture, but because it deteriorates with time, it should not come into touch with acidic or alkali surfaces.

Each kind of polyester resin is tailored to fulfill certain performance standards, it may be used in a wide range of sectors and contexts. To produce a fabric that is more resilient to ripping and does not shrink or wrinkle, polyester resin is frequently mixed with cotton. This material is also used to produce carpets, ropes, automobile interiors, and other consumer goods in addition to cloth.

Polyester resin is a popular material for arts and crafts projects, as well as for sculpting and manufacturing ornamental things due to its adaptability, durability, and shining finish. Polyester resin is also used to make parts for cars, including the body, windshield, and hood, because of its cost-effectiveness and ease of molding. Polyester resin is frequently used in the casting of hulls and decks because of its great durability and water-resistant qualities.

Polyester resins come in a variety of forms that don’t react with food or drink, which makes them perfect for packaging. It may be made into a film or a preform for molding, which can then be used to make things like plastic cups, boxes, and bottles.

Urethane Resin

Urethane resins are perfect for finishing boat hulls and external molding projects because of their extreme durability and UV resistance. They are available in two forms: solvent-borne and water-borne. The latter is considered to be a more ecologically friendly option because of its lower levels of toxicity than the former. Furthermore, urethane resins are superior to epoxy resins in some situations because they provide superior scratch resistance while having a lower hardness rating.

This resin has several exceptional qualities, including its liquid texture and low viscosity, which make it ideal for molding, crafting, creative projects, and material preservation. It may be used with colorants to get the desired color and permits elaborate elaboration.

Many materials, including concrete, metal, plastic, and wood, are frequently coated with polyurethane resin for protection. It forms a strong, glossy shield that is impervious to UV rays, chemicals, and abrasion.

Varnish Resin 

When a durable finish that is excellent at withstanding wear and tear over time is required in furniture applications, varnish resin is frequently used. It is composed of solvents and oil-based compounds, which offer further defense against peeling and cracking in damp or extremely hot environments. Finally, varnish offers better UV protection than typical lacquer, which, if left untreated, tends to yellow with time.

varnishing a table

Silicone Resin 

Because of its great adherence to wood, clear finish, affordability, and ease of application, polyester resin is a popular choice for woodworking tasks. It performs better financially than most other varieties when producing huge quantities of intricate molds. It is most frequently used on outdoor furniture, but because it deteriorates with time, it should not come into touch with acidic or alkali surfaces. 

Due to its numerous exceptional qualities, silicone resin has grown in importance and is utilized extensively across a wide range of sectors and businesses. Surfaces can be made heat, UV, water, and weather-resistant with silicone resin coatings. 

To guard against adverse environmental conditions, the construction sector frequently employs it for buildings, bridges, and industrial structures. In addition, it is used in the manufacturing of paper and textiles.

Silicone resin is used for craft molds and plastic molding because of its flexible and resilient qualities. It is particularly useful for molds that have a lot of tiny, angular features since it is simple to remove from the mold.

Natural resins 

Conifers including pine, birch, and many palm plants are the source of natural resins. These trees’ sap is made up of volatile terpenes that are removed in a viscous form and eventually solidify. Impurities are common in natural resins, and it can be challenging to anticipate how they would react when exposed to heat.

Synthetic resins 

Molecular polymerization creates very stable viscous materials that resemble those found in trees, which is how synthetic resins are made. Because of this synthetic resin’s purity and more consistent behavior, it has become more and more popular. Prior to curing, the clear low viscosity resin available at craft supply stores has to be combined with hardening catalyst.

For more on the safe use if this resins click this link:

2.1 Understanding the Resin Casting Process

Resin casting is a plastic casting technique in which a liquid synthetic resin is poured into a mold and allowed to solidify. Dentistry and industrial prototypes are the two main industries that employ it for small-scale manufacturing. It is utilized in small-scale jewelry manufacture as well as the creation of collectible toys, figurines, and figures by amateur enthusiasts with low initial expenditure.

Before the resin hardens, it is contained in a mold while casting resin. Since resin is a dangerous substance when liquid (but not harmful when cured), creating resin art calls for a few unique items that you might not already have in your craft supply closet in addition to safety gear. Making resin art isn’t hard, but it does need some patience because each process needs to be done carefully.

The role of molds

liquid resin being poured into a half body mold

Using casting resin molds, you may create a precise mold of an object you want to show off or duplicate. After that, resin is put into the mold to precisely duplicate its shape. You may then display the resulting 3D object wherever you choose.

A special kind of epoxy, or more precisely, casting resin, is typically needed for casting molds. Another name for this is deep pour resin. Because this kind of resin cures more slowly, thicker pours may be made with it.

However, molds may also be utilized with coating and tabletop epoxies. Just remember that since they normally only permit up to 1/4 inch thickness per application, it will probably need several pours.

Almost anything may be made with casting molds. To preserve and show important artifacts, people create a mold to hold the resin and then insert the objects into the mold. A very creative item may be made by applying dye or spray painting a duplicate of an object.

Types Of Molds

Molds for casting resin can be manufactured by hand or bought. You may select from a variety of mold types to fit the needs of your project. Numerous materials, such as silicone rubber and latex rubber, can be used to create flexible molds. A lot of casting resin professionals utilize glass jars and store their finished product inside for consumption. This is a lovely feature that gives your project more security. Putting some modest items on display in a small glass container with space for a tea light on top is one of my favorite crafts!

If the mold is formed by hand, it is crucial to make sure that all required components are available. A razor or x-acto knife, mold putty, the object to be duplicated, a timer, and some casting resin are among the necessary supplies. Even though most molds are formed in the same way, it is best to use the mold putty according to the instructions on the box. It immediately transforms into a substance like to putty or clay when the mold-making process begins.

Mixing and curing

Wear nitrile gloves and make sure the workstation is well-ventilated before combining the resin and hardener. It is advised to use nitrile gloves when mixing resin since latex gloves might impede the chemical reaction.

Calculating quantities

When learning how to effectively mix resin, it’s important to keep in mind that the right amount of hardener and resin must be calculated. The type of resin used can affect the measurements required for each part. Always carefully follow the directions, regardless of the tool used.

The most crucial factor to keep in mind while casting resin is that incorrect measurements might result in the resin not setting properly. Re-agent and hardener should always be measured out individually for maximum accuracy; add or subtract as necessary.

It is important to remember that measuring and eliminating bubbles might be facilitated by preheating the resin. Use a dish filled with warm water or preheat the bottle over a heater.

Get mixing

After the resin and hardener have been added to their respective cups in the appropriate amounts, take the hardener and begin to pour it into the resin-filled cup. Next, begin blending using a stirring stick. Mix with a constant motion. When the mixture is whipped, bubbles may form that will eventually solidify in the mold. Being as thorough as possible without hurrying is the secret to stirring resin. Maintaining that degree of precision requires precise measuring in addition to being careful to remove any traces of hardener from the plastic cup.


The hardener’s cure time determines how long the stirring should take. Stirring for up to two minutes is good, but if you’re using a fast-curing recipe, you should stir a little bit faster. Use the mixing stick to scrape along the edge of the cup to ensure that all of the hardener has been properly mixed through and that no hardener remains missing.


For resin to cure correctly, precise measurement and thorough mixing are required. For information on the proper resin-to-hardener mix ratio, consult the technical data sheet or the label of the hardener.

Pour the appropriate amounts of hardener and resin into a sanitized paper, metal, or plastic container that is free of wax.  Glass and foam containers should not be used due to the risk of exothermic heat accumulation. Never try to change the mix ratio to shorten cure time. For resin to properly cure and acquire its physical qualities, a precise ratio is necessary.

When resin and hardener are mixed, a chemical process takes place that solidifies the liquid materials. The moment to heal is during this metamorphosis. Resin goes through three states throughout the curing process: liquid, gel, and solid.

Curing is a crucial step in the resin application process, and there are a few different approaches to take: 

UV light- With UV light curing, resin may be hardened in as little as 30 seconds using a UV lamp. But just as no two resins are the same, neither are UV lights made equally strong. It is noteworthy that UV light curing units can cost anything from $500 to $1000. For a particular product, ask the manufacturer about UV light curing.

Heat- By using heat, the curing process of the resin can be sped up using the hot curing technique. Depending on the resin being used, hot curing might take five to ten minutes. A consistent heat source, such as an epoxy curing blanket, radiant heater, or oven, is required.

Heat Guns – A hair drier, infrared lights, or heat gun can be used to partially cure resin, although their effectiveness is not guaranteed. It might be difficult to verify that the parts have been heated to the proper temperature for the advised amount of time if they don’t heat the part uniformly. It is necessary to examine the cured product’s hardness.

Curing happens more quickly at higher temperatures. The temperature of the resin is influenced by three factors:

  • The ambient temperature, which is the overall temperature of the place where you are working.
  • The ambient temperature also includes the temperature of the surface on which you have applied the epoxy.
  • Exothermic heat is the heat that the epoxy produces while curing.

Use a slower hardener to extend or sustain your open time in response to rising temperatures. Smaller amounts can also be mixed and consumed rapidly. Alternatively, to lengthen the open time, pour the epoxy mixture onto a larger surface area container (like a roller pan) and let the exothermic heat disperse. The longer the mixture’s available open time for coating, lay-up, or assembly, the sooner it is transferred or applied (after full mixing).

In cold weather, increase the temperature over the minimum application temperature specified by the hardener by using a quicker hardener or applying more heat. Before mixing or after applying the resin, warm it by using a hot air cannon, a heat lamp, or another heat source. Hardeners should not be heated before being mixed with resins. Using extra heat in curing shortens the resin’s cure period.