Epoxy resin has become extremely popular in crafting, decoration and technical applications. It’s no surprise — it allows you to achieve impressive, durable and aesthetically pleasing results. However, to get the outcome you expect, it’s important to take care of a few key aspects.
Several common problems can appear when working with resin — especially for beginners, though not only. Air bubbles, uneven, cloudy or contaminated surfaces are just some of the issues that can ruin the final look. To avoid disappointment and achieve a satisfying effect — regardless of your experience level — it’s worth learning a few proven rules.
Make sure you work in a well-ventilated space and protect your skin and eyes — epoxy should always be handled while wearing gloves, avoiding contact with the skin and inhalation of fumes. When working with resin, it is recommended to use protective masks and safety glasses. Safety comes first. Once cured, epoxy resin becomes a harmless, non-toxic surface.
Your workspace is very important for achieving a good final result. Although cured resin is resistant to weather conditions, the ambient temperature during work plays a crucial role — it affects the time and quality of curing. Too low a temperature can slow the reaction or prevent the resin from curing properly. Too high a temperature accelerates the reaction, which may cause overheating, air bubbles or deformation. Resin cures best at a stable temperature above 18°C, ideally between 20–25°C. Recommended values may vary depending on the resin type.
Low humidity is just as important. Excess humidity can cause the surface to become cloudy and interfere with the curing process, especially in thick-pour resins. It is best to keep indoor humidity at 50–60%. Poor conditions may also cause the material to yellow during work.
Prepare your workspace well: protect the floor and work surface (e.g., with foil or a protective sheet) to avoid spills. It is crucial to have a perfectly level surface for your molds — otherwise, the resin will flow toward the lower side. The base must be flat and stable. Cleanliness is equally important: dust, lint and small particles easily settle on freshly poured resin and may become permanently embedded. During curing, it’s a good idea to cover the piece with a plastic container or cardboard box to protect it from contamination. Make sure the cover leaves enough space for air circulation. Resin cures slowly, so choose a place where the mold will not be moved during that time.
The curing process of epoxy resin is the result of a chemical reaction between the resin and the hardener. This reaction is exothermic — it produces heat. For this reason, it is essential to follow the manufacturer’s recommendations for maximum — and, in some cases, minimum — casting thickness.
For most epoxy resins, pouring a single layer that is too thick can cause excessive heating, overheating of the mixture and the resin boiling effect. A layer that is too thin, below the recommended minimum, will cure much more slowly because the reaction occurs less intensively.
The ratio depends on the product and the manufacturer. Many systems are available on the market — some require weight ratios like 60:100 or 40:100. It’s important to pay attention to this — a 2:1 ratio is much easier to use and helps avoid mistakes that can affect the final outcome.
It is very important to check the units on the packaging. Make sure the ratios refer to weight or volume — this is crucial because resin and hardener have different densities. Manufacturers may also label the product in grams or milliliters.
Keep in mind that measuring by weight and by volume gives different results.
When measuring by weight, you can use a single container — weigh Part A, then add Part B. Part A is thicker, while Part B has a density similar to water.
When measuring by volume, things get more complicated. Volumes are not additive — the total will not equal the simple sum of the parts. Because resin and hardener have different densities, volume ratios will not match weight ratios. If you use a measuring cup with milliliters, be sure to use a separate cup for resin and a separate one for hardener.
Air bubbles are one of the most common problems in resin casting, and they can appear for several reasons.
When casting porous materials such as wood, it is recommended to start by applying a thin sealing layer (0.2–0.5 mm). This layer laminates the surface, closes the pores and prevents trapped air from escaping. If this step is skipped, the air inside the wood may be released during curing, creating unsightly bubbles in the final product.
Bubbles can also form during mixing and pouring. To avoid them, mix slowly and thoroughly, without rapid movements, and pour the mixture from a low height — ideally along a stir stick or spatula. Cold resin is harder to mix, so make sure it is at room temperature before starting, which ensures the proper consistency.
The mixing stage is crucial not only because of bubbles. Even more important is ensuring that both components — resin and hardener — fully combine. After joining the two parts, mix very thoroughly, scraping the sides and bottom of the container. Then pour the mixture into a new, clean container and mix again. Because the components have different viscosities, resin tends to stick to the walls, which may result in unmixed areas if you use only one container. Transferring and remixing ensures that the components blend evenly and the resin is fully prepared for use. The more times this process is repeated, the more certain you are that the components are completely combined.
If bubbles appear despite careful mixing, you can remove them with a heat gun or torch, gently warming the surface right after pouring — briefly, without touching the resin.
To achieve maximum clarity and a crystal-clear finish, both proper preparation and choosing the right product are essential. Keep in mind that not all resins have the same color purity — some may have a slightly yellow tint or lower UV resistance, which affects long-term clarity. It is also important to remember that any resin exposed to prolonged sunlight may yellow to some extent.
Once the casting is fully cured, it is good practice to lightly sand the surface with fine-grit sandpaper (e.g., 1000–2000), then apply a high-clarity clear varnish. The varnish creates a perfectly smooth finish, enhances shine, deepens optical clarity and masks minor sanding marks — and most importantly, it prevents yellowing.
Technicqll epoxy resins for thin and thick castings offer excellent clarity and a crystal-clear appearance. Thanks to their high UV resistance, they maintain transparency for a very long time. The 2:1 weight ratio makes dosing and mixing precise and convenient. The extended working time — up to 50 minutes — allows you to arrange all elements comfortably without rushing. The resin has enough time to cure evenly, without the risk of overheating, wave formation or the “boiling” effect. It is suitable for both beginners and experienced users who seek top-quality epoxy resin.
