A casting resin succeeds or fails on what you can see through it. For river tables, encapsulated objects, and clear castings, the resin has to pour deep, release its own bubbles, and stay colorless for years under light.

What a Casting Resin Is For

A casting resin is a two-part epoxy formulated for depth. It cures slowly enough to manage the heat a thick section generates and clear enough that embedded wood, objects, or pigment read sharply through the pour. This is a different job from a coating resin, which is built for thin, self-leveling topcoats and does not hold clarity in thick sections.

Incure’s clear epoxy casting resin is formulated for wood infills, molds, and encapsulation where visual depth and long-term stability matter.

Clarity and Color Stability

The resin cures water-clear, showing embedded objects and natural grain without cloudiness. A UV-resistant formulation holds that clarity under prolonged light exposure, where many resins yellow and degrade. For pieces intended for long display or partial outdoor use, that color-hold is the difference between a finish that ages well and one that discolors within a season.

Air Release

Bubbles are the common defect in deep pours. A self-degassing formulation lets trapped air rise and dissipate on its own, reducing reliance on vacuum degassing equipment. The result is a cleaner pour with less rework, though good practice still matters: seal porous wood first, mix without whipping air in, and pour at a controlled temperature.

Pour Thickness

Casting depth depends on the mold and the mass:

• Directly into wood: thick single-pour infills up to roughly 25 mm, useful for river tables and filling voids and cracks.
• Into silicone or plastic molds: up to roughly 50 mm in a single pour, with caution. Large volumes generate significant exotherm, so control ambient temperature and consider pouring in layers for the deepest or largest castings.

Runaway exotherm in an oversized pour can crack the casting, discolor it, or in extreme cases scorch. When in doubt, layer.

Where It Fits

• Furniture manufacturing: river tables, knot and void fills, and wood-and-resin hybrid panels.
• Wood and resin art: lamps, decorative panels, and turned pieces with clear resin elements.
• Clear castings: sculptures, figurines, and paperweights that show internal detail.
• Encapsulations: preserving dried botanicals, stones, or small artifacts in a clear block.

Working Characteristics

• Simple mix ratio with a forgiving working time for consistent results.
• Low odor, for a more comfortable shop environment.
• Self-degassing, cutting the need for specialized equipment.
• No specialist tooling required, which lowers the barrier for small shops.

Casting vs. Coating

The cured open face of a deep casting is rarely mirror-flat on its own and usually needs flatting and polishing to a gloss. For a perfectly smooth top surface, pour a thin coat of coating resin over the cured casting. Selecting the right resin for each role, depth clarity from a casting grade and a flat gloss from a coating grade, is what produces a finished piece that looks right from every angle.

Where a metal or stone inclusion sits inside a wood casting, the different expansion rates load the resin cyclically as temperature shifts. Our guide on how CTE mismatch causes adhesive bond failure covers that mechanism.

Email Us with your pour depth, mold type, and whether the piece will see sunlight, and Incure’s team can confirm the right resin and pour plan.

Getting a Clean Casting

• Seal the wood. A thin sealing coat stops air in the grain from bubbling up through the main pour.
• Condition the resin. Bring both parts to a stable room temperature before mixing.
• Measure exactly. Off-ratio epoxy stays soft, tacky, or hazy and cannot be corrected after cure.
• Pour at the right depth. Respect the per-layer maximum for your mold type and layer deeper work.
• Protect the cure. Cover against dust and drafts until the surface is firm.

For help choosing between epoxy and UV chemistries where clarity drives the decision, see our comparison of UV glue and epoxy for transparent bonding.

Managing Exotherm in Deep Pours

Epoxy cure is exothermic, and heat that cannot escape a thick section accelerates the reaction, which generates more heat. In a large mold this feedback can push the resin past 90 degrees C, causing yellowing, cracking, internal bubbles, or a scorched core. Controls:

• Pour in layers. Let each layer cool and gel before the next. This is the single most effective control for large volumes.
• Lower the mass temperature. Start with cool resin and a cool room, around 18 to 20 degrees C.
• Choose the geometry. A wide, shallow pour sheds heat better than a deep, narrow one of the same volume.
• Use a slow grade. Deep-pour casting resins are formulated with a long working time specifically to spread the exotherm over hours.

Common Casting Defects

• Bubbles rising from the wood: the substrate was not sealed. Apply a thin seal coat and let it cure before the main pour.
• Cloudiness or a milky cast: moisture contamination, cold resin, or condensation on a chilled mold. Keep everything warm and dry.
• Soft or tacky cured resin: off-ratio mix. Weigh both parts and mix thoroughly, scraping the container.
• Cracks radiating from an inclusion: exotherm stress or a sharp-cornered object concentrating stress. Layer the pour and radius embedded objects where possible.

Working With Incure

Incure supplies clear epoxy casting and coating resins with application support on substrate preparation, exotherm management, and finishing, for makers and production shops alike.

Contact Our Team to discuss a casting project and select the right resin.

Visit www.incurelab.com for more information.