Overview of casting resins

Which casting resin should I use? We are happy to answer that question. In this article you can read which casting resins are most suitable for your end goal. In the table below, you will find a clear overview of our different casting resins and the pros and cons of these products.

What is casting resin?

Casting resin is a fiber-reinforced plastic that consists of two components. You must mix these two components together before use. When this plastic hardens, it is a plastic that is stronger than 'normal' plastic. You can use casting resin for different purposes. For example, it is widely used for casting electronics, for the production of plastic products and for floors. Furthermore, the material is also widely used for coating and protecting wooden furniture.

In this article we will delve into the fascinating world of casting resins, exploring their various applications and unique properties that make them the go-to choice for so many artistic endeavors. We supply casting resins quickly from stock. Which casting resin is used for which applications? What are the advantages and disadvantages of each of these resins? Check the table below.

  Advantages Disadvantages
RESION UV Resin Art Epoxy (LV)
  • Low viscosity
  • Simple 2:1 mixing ratio
  • Very UV stable
  • Highly transparent
  • Adheres to almost all substrates
  • Very suitable for jewellery
  • Temperature resistance (40-45 °C)
  • Curing time (complete after 3-5 days)
RESION UV Resin Art Epoxy (MV)
  • Medium viscosity
  • Simple 2:1 mixing ratio
  • Very UV stable
  • Highly transparent
  • Adheres to almost all surfaces
  • Very suitable for paintings, coasters and jewellery
  • Very suitable in combination with Piñata Alcohol Ink
  • Temperature resistance (40-45 °C)
  • Curing time (complete after 3-5 days)
RESION UV Resin Art Epoxy (HV)
  • High viscosity
  • Simple 2:1 mixing ratio
  • Very UV stable
  • Highly transparent
  • Adheres to almost all substrates
  • Very suitable for geodesics
  • Very thick so more difficult to mix
  • Temperature resistance (40-45 °C)
  • Curing time (complete after 3-5 days)
Polyester casting resin
  • Fast curing
  • Casting of organic materials is possible
  • Can be coloured with many pigments
  • Can also be coloured with transparent pigments
  • UV resistant
  • Very good post-processing (grinding, drilling, polishing)
  • Easy processing
  • Shrinks
  • Stinks when processed
  • Flammable
  • Not suitable for casting in a wooden mould
Epoxy UV casting resin
  • Odourless
  • UV resistant
  • Very clear system
  • Can be coloured with glow-in-the-dark filler
  • Can be coloured with pigments
  • Transparent tinting with pigments
  • Relatively cheap
  • No shrinkage
  • Very good post-processing (grinding, drilling, polishing)
  • Long curing time (min. 24 hours)
  • Temperature resistance
Mastercart 1-2-1 ArtWork Resin
  • Odourless
  • Faster curing as epoxy casting resin
  • Ability to cast thick layers without dam
  • Very suitable as system for paintings
  • Clear casting system
  • Built-in UV stabiliser
  • Lower mechanical strength than epoxy casting resin
  • Temperature resistance of around 50 degrees
  • Costly


PU casting resin (polyurethan resin) 
  • Odourless
  • Clear available
  • Can be coloured with pigments
  • Available in different types and hardnesses
  • Long curing time for transparent PU
  • Sensitive to moisture
  • More difficult to finish
Silicone rubber
  • Easy to process
  • Relatively inexpensive
  • Takes on very detailed details
  • Limited lifespan
  • Cannot be post-processed

Polyester casting resin

Polyester casting resin is used for various applications, such as casting wedding bouquets, but also for repairing boats and other polyester products and various other objects. This casting resin is suitable for technical workpieces. The result of polyester casting resin is hard but slightly flexible.

Polyester casting resin shrinks slightly, this should be taken into account when pouring the resin into an object.

The colour is transparent. In very large castings, the colour may appear slightly purple (just as glass may appear slightly green). Polyester casting resin is UV resistant.

Polyester casting resin can be coloured with polyester pigments. These can be the standard pigments, but transparent polyester pigments are also available. Add a little pigment to the casting resin and determine whether the desired effect has been achieved before adding more pigment.

Processing polyester casting resin

Polyester casting resin is easy to process. Weigh a quantity of casting resin on a scale. Depending on the size of the object, add 1% to 3% MEKP hardener. For large objects (from approx. 2 kg) 1% is sufficient, for small objects (250 g and less) 3% is recommended. The temperature can also play a role in this. If the casting resin mixture is very warm, you can decrease the amount of hardener slightly. If the temperature is cold, please increase the amount of hardener slightly.

Mix the casting resin and hardener thoroughly. Also scrape the wall and bottom of the mixing bowl several times. Then pour the resin into the mould. Always start at the lowest point and let the casting resin flow gently into the mould. If necessary, tap the mould to release air bubbles to the surface. An unwilling air bubble can possibly be brought to the surface with a skewer.

Now allow the casting resin to harden slowly before removing it from the mould.

Epoxy casting resin 

Epoxy casting resin is a transparent casting resin that is virtually shrink-proof. This makes this resin very suitable for casting objects. The resin can be used for decorative purposes, such as jewellery, table tops, bar tops and paintings, but also for technical purposes, such as casting electronics, filling junction boxes to protect against water, filling cavities and flat casting foundations for machines.

Epoxy casting resin can be combined with various fillers, such as dry sand, gravel, pieces of metal (punch caps) or other fillers.

The colour of epoxy casting resin is virtually transparent. Do you want a highly UV-resistant casting resin? Then choose RESION UV Resin Art Epoxy or RESION UV Epoxy.

Epoxy casting resin can be coloured with epoxy pigments. When you add a very small amount of pigment, you are left with a transparent epoxy casting resin.

Glow in the dark

An epoxy casting resin that should be mentioned separately is the glow in the dark epoxy casting resin. This casting resin is yellow or white in colour and will absorb energy during the day. As soon as it gets dark, the casting resin will light up in green or blue. The afterglow time is about 8-12 hours, depending on the conditions. The possibilities of this resin are endless, just think of house numbers, jewellery, art objects, light switches, etc.

Epoxy resin casting

Epoxy casting resin must be weighed accurately. Use a scale for this and do not deviate from the specified mixing ratios (2:1 for the resin art epoxy and 100:60 for the UV epoxy casting resin) when pouring the resin. Place a mixing bowl on a scale and tare the scale (reset to 0). Now pour an amount of A-component into the mixing bowl and read the weight. Now determine the amount of B component that needs to be added. Tare the scale again and add the correct amount of B component. Then mix the A-component and the B-component carefully. Scrape the sides and bottom of the mixing bowl several times. For critical pours it is advisable to pour the mixture into a second mixing cup and then mix again. This will ensure proper mixing and a tack-free cure.

Then start pouring resin over or into the object. Make sure you always pour at the lowest point and pour no more than 3 cm thick at a time. Air bubbles will rise to the surface. After about 10 minutes most of the air bubbles will have disappeared. For a perfectly smooth finish, you can briefly wave a gas burner over the surface. This will break air bubbles and the surface will flatten completely.

If possible, you can place a container over the object to prevent dust from falling into the resin. The next day the resin is hard enough to continue working. The casting resin will harden further in the following days.

Polyurethane casting resin 

PU casting resin is a popular casting resin for making objects such as cars, aircraft or military equipment in model making. The resin takes over every detail of the mold (often a silicone mold) and is easy to process with simple tools. The resin is easy to paint.

PU resin is hard but also impact resistant and therefore also suitable for technical products such as machine parts. The fast curing time ensures that multiple products can be made per mould in 1 day. 

Polyurethane casting resin is beige in colour and can be coloured with special pigments for polyurethane.

Working with polyurethane casting resin

Polyurethane casting resin is easy to process. The casting and processing of the resin is virtually the same as that of polyester casting resin and epoxy casting resin. Pay close attention to the mixing ratio with the PU casting resin. This may vary per product and must be strictly followed. Use a scale for this.

Carefully weigh the A and B components on the scale and carefully mix the two components. Make sure that the packages are closed again after pouring out the A and B components. PU casting resin is very sensitive to moisture. This causes air bubbles in the result.

Pour the PU resin into the lowest part of the object. Tap the mould to release any air bubbles and then leave the PU resin alone. This will harden faster or slower depending on the type of casting resin. After curing, the casting resin can be removed from the mould.

Silicone rubber

Silicone rubber can hardly be called a casting resin, but we will not leave it out of this overview. Silicone casting rubber is mainly used for manufacturing flexible moulds. These moulds are then used to cast products. Silicone muolds are also used for casting soap, chocolate, sugar, etc.

Our casting silicone is flexible, tear-resistant and very strong. The silicone is available in four hardnesses (Shore 8Shore 15Shore 25 and Shore 40) and can be mixed together for intermediate hardnesses.

thickener is available for the silicone rubber. When this is added to the silicone rubber, a thicker paste will be created that can be used as ironing silicone, which can be applied to a surface with a brush or spatula.

Working with silicone rubber

Weigh both components well and mix them carefully. Pour the mixture into a second mixing bowl and mix thoroughly again. This prevents unmixed silicone from entering the workpiece. Then pour the silicone with a thin stream into the deepest point of the workpiece and let the silicone find its own way. The silicone can be processed for 2 hours. During these two hours, air bubbles will rise. The relatively low viscosity of this silicone rubber ensures a bubble-free result.

After approximately 8 hours, the silicone has hardened sufficiently to be further processed.

More information on casting resin?

After reading this article, will you start casting resin or are you looking for the right products? At Polyestershoppen.nl you will find a wide range of casting resin and associated products. Our specialists are happy to help you with information about these products and their use. Do you have any questions or can we help you with anything else? No problem! Please contact us, we are ready to help you!


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