Deep pour epoxy resin (also known as casting epoxy resin) and tabletop epoxy resin (also known as coating epoxy resin) both fall under the two-component epoxy resin system, yet they exhibit significant differences in physical properties, construction requirements, performance characteristics and application scenarios due to distinct core formulation designs and functional orientations. The most crucial difference lies in their working thickness, which in turn leads to a series of consequent differences.

1、Physical Characteristics: Variances in Viscosity and Flowability

Viscosity is the most intuitive difference between the two, directly determining their flow capacity and filling performance.

Tabletop epoxy resin: It has a relatively high viscosity after mixing, with a honey-like consistency and low fluidity. This property allows it to spread slowly and self-level on flat surfaces, ultimately forming a uniform coating of approximately 3 mm in thickness naturally. It can cover surface gaps without additional troweling, making it ideal for creating smooth surface finishes. Some low-quality tabletop epoxy resins only have a self-leveling thickness of about 1.5 mm and require multiple coats to achieve a durable thickness.

Deep pour epoxy resin: It features an extremely low viscosity, almost water-like, with exceptional fluidity. It can easily penetrate wood gaps and mold corners, while facilitating the natural floating and release of air bubbles to avoid bubble residue during thick-layer casting. Its low-viscosity property is the foundation for achieving thick-layer casting, enabling the formation of a relatively thick molded layer in a single application.

2、Construction Parameters: Pouring Thickness, Working Time and Curing Cycle

Tabletop Epoxy Resin: The recommended single pouring thickness is 5–10 mm. If the thickness exceeds this range, the heat generated during curing cannot dissipate in time, which will trigger thermal runaway, leading to surface yellowing, cracking, and shrinkage deformation.It has a relatively short working time, with an operational window of only tens of minutes to 1 hour after mixing. The curing speed is fast: it can achieve initial curing at room temperature in 12–24 hours and complete curing in 24–72 hours. It also supports repainting within a short time (3–6 hours).The mixing ratio is mostly 1:1 by volume, and it has a low operation threshold.

Deep Pour Epoxy Resin: Specifically designed for thick-layer pouring, it can achieve a single pouring thickness of 12–50 mm. To control heat release, its formula adopts a slow-curing system, resulting in an extremely long working time of 3–10 hours or more. For some large-volume pouring products, the working time can be as long as 10 hours, which is sufficient to complete complex mold filling and bubble treatment.Its curing cycle is relatively long: initial curing takes 24–36 hours at room temperature, and complete curing may take several days. It is not suitable for thin pouring; otherwise, it will cause incomplete curing, sticky surfaces, or insufficient hardness.The mixing ratio is mostly 2:1 or 3:1 by volume, with a high requirement for mixing ratio accuracy.

3.Performance Characteristics: Hardness, Heat Resistance, and Stability

Tabletop epoxy resin focuses on surface protection, while deep pour epoxy resin emphasizes molding strength.

Tabletop Epoxy Resin: After curing, it exhibits high hardness, with a Shore D hardness ranging from 70 to 85. It boasts excellent scratch and wear resistance, coupled with superior water and heat resistance, effectively resisting bumps, water stains, and high-temperature contact during daily use. Most products are formulated with UV-protective additives, which reduce yellowing and discoloration caused by sunlight exposure, making them ideal for surfaces exposed to indoor environments for long periods. However, it has poor flexibility and relatively high brittleness, which may lead to cracking under severe impact.

Deep Pour Epoxy Resin: Its hardness after curing is lower than that of tabletop epoxy resin—a deliberate design choice. The deep pour formulation requires a slower reaction rate to enhance toughness and reduce internal stress, resulting in a slightly “softer” yet more flexible material compared to tabletop epoxy resin. It typically has a Shore D hardness of 60 to 75. Its key advantages include low curing shrinkage, excellent dimensional stability after thick-layer molding, and resistance to deformation. Due to its slow curing process, the internal stress is evenly distributed, ensuring overall toughness that surpasses that of tabletop epoxy resin. It also offers good yellowing resistance, but its UV protection capability is generally weaker than that of tabletop epoxy resin, so it may still discolor when exposed to prolonged sunlight.

4、Applicable Scenarios: Functionality Determines Application Scope

The applicable scenarios of the two are strictly aligned with their performance characteristics and cannot be arbitrarily substituted, otherwise it will lead to project failure.

Tabletop Epoxy Resin: Its core application is surface coating protection, suitable for creating flat, high-gloss, and durable surface layers. Typical applications include sealing the surfaces of dining tables, bar counters, countertops, and solid wood furniture, as well as curing the surface layers of coasters, decorative panels, and mixed-media artworks. It can be mixed with pigments such as mica powder and alcohol ink to create colorful decorative surfaces, while also sealing wood and preventing deformation caused by moisture absorption. Note that if it is used outdoors, additional UV protection additives must be added or UV-protective tabletop epoxy resin should be purchased.

Deep Pour Epoxy Resin: Its core application is three-dimensional molding and thick-layer filling, suitable for the production of molded parts that require a certain thickness. Typical applications include river tables (filling wood gaps), resin castings, silicone mold molding (jewelry, pen holders, ornaments), large-scale artworks encapsulation, and building gap filling. Objects such as metal, wood, and flowers can be embedded and encapsulated within it to create a transparent and three-dimensional effect. Due to its insufficient hardness, large molded parts (such as river table tops) usually require an additional layer of tabletop epoxy resin to be applied on the surface, balancing thickness and surface durability.

5.Summary and Selection Principles

Essentially, tabletop epoxy resin is a “coating resin” focused on thin-layer protection and high-gloss decoration; deep pour epoxy resin is a “molding resin” designed for thick-layer filling and three-dimensional molding. The selection of the two must follow the “thickness matching” principle:

For thin-layer (1–3 mm) surface protection and high-gloss decoration, with a focus on fast curing and high hardness, choose tabletop epoxy resin.

For thick-layer (≥3 mm) molding, gap filling, and object encapsulation, requiring bubble and shrinkage control, choose deep pour epoxy resin.

For complex projects (e.g., river tables), a combination can be used: deep pour epoxy resin fills gaps to achieve the required thickness, while tabletop epoxy resin is applied to the surface to enhance hardness and wear resistance.

Color mixing is an extremely crucial process when using deep pour epoxy resin for creating large artworks, river tables and other pieces. It requires a balanced consideration of color uniformity, curing stability and visual effects. Due to the fluidity, bubble release characteristics of deep-pour epoxy resin, as well as the amplifying effect of its thickness on color presentation, the color mixing process differs significantly from that for surface coating. Below are some of Jinhua’s experiences in color mixing for deep-pour epoxy resin, provided for your reference.

1.Pigment Selection and Compatibility Testing

The chemical properties of deep-pour epoxy resin are sensitive, making pigment selection a critical step that directly impacts the curing performance. It is therefore essential to avoid non-specialized pigments in the first place and select the suitable pigment type according to specific requirements.

（1） Recommended Pigment Types and Their Applicable Scenarios

Specialized liquid resin dyes: Best suited for deep pouring, with excellent solubility that enables complete fusion with resin, delivering a uniformly transparent or translucent hue without any graininess. Ideal for creating gradient and transparent effects (e.g., simulating water bodies or amber textures). A single drop can color 20–100g of resin (standards vary by product; refer to the product instructions), offering easy dosage control and minimal impact on curing.

Mica powder pigments: Powder-form with natural mineral ingredients, they create pearlescent, metallic luster or a delicate frosted texture, ideal for crafting deep-pour artworks in retro and gorgeous styles (e.g., resin river tables, decorative ornaments). Note to disperse in advance to prevent clumping.

Specialized epoxy resin pastes/color gels: High in concentration and hiding power, they are suitable for projects requiring solid, opaque effects, such as custom color blocks and embedment encapsulation. Strictly control the dosage to avoid compromising the resin’s fluidity.

Alcohol inks: Ideal for creating artistic textures like marble and cell patterns, with vivid colors and excellent spreadability. For accent use only; excessive amounts will damage the resin curing system, leading to a tacky surface or cracking.

（2）Prohibited Pigments

Non-specialized colorants such as food colorings, regular nail polishes and low-cost craft pigments can easily cause incomplete curing of the resin (resulting in a tacky or soft finish), color bleeding or excessive bubbling, which completely ruins the effect of deep pouring. In addition, any colorants containing water or oil must be avoided entirely to prevent curing failures.

（3）Compatibility Testing

Regardless of the pigment used, a small-batch test must be conducted before official color mixing: Take 50–100g of resin (before mixing components A and B in the specified ratio), add the planned dosage of pigment, stir thoroughly and pour into a small mold. Observe the curing condition for 24–48 hours. Proceed with mass mixing only after confirming no abnormalities and that the color meets expectations. This step is mandatory especially when using a new brand of pigment or resin for the first time.

2、Standard Color Mixing Operation Procedure

Color mixing for deep-pour epoxy resin shall follow the principles of “Disperse First, Mix Later, Control Dosage, Prevent Bubbles”, with the procedures as follows:

（1） Preparations

Set up a clean, well-ventilated and constant-temperature workbench (20–25℃) to prevent dust contamination. Prepare dry mixing containers, stirring rods (silicone rods are recommended for easy cleaning and reduced bubble formation), measuring cups, pigment tools and test molds. Bring the deep-pour epoxy resin to room temperature in advance to ensure stable fluidity.

（2）Pigment Pre-dispersion (Critical Step)

For powder pigments (e.g., mica powder), first mix a small amount of Resin Part A (without hardener) with the pigment and stir into a uniform, particle-free slurry, then pour the slurry into the remaining Part A and stir thoroughly. This step prevents pigment clumping and avoids defects such as color spots and streaks after deep pouring. Liquid pigments can be directly added to Part A in small, separate portions without pre-dispersion, but the addition must be done dropwise and slowly.

（3）Resin Mixing & Color Tuning

Accurately weigh Resin Parts A and B in accordance with the ratio specified in the resin manual (usually 2:1 or 1:1 by volume). First, stir Part A with the pre-dispersed pigment thoroughly to ensure uniform color throughout (stir slowly in a circular motion along the container wall to minimize bubble generation).

Add Part B and continue stirring for 3–5 minutes until the mixture becomes completely transparent and free of floccules. Scrape the bottom and side walls of the container repeatedly during stirring to avoid residual unmixed resin, which may cause local color unevenness or poor curing.

Color fine-tuning: Follow the principle of “small amounts, multiple additions”. Stir for 30 seconds after each pigment addition before checking the color. Since deep pouring amplifies color concentration (the color of a thick layer is 30%–50% darker than a thin layer), leave room for lighter color during fine-tuning to prevent the final color from being overly dark.

（4） Bubble Treatment & Settling

After color mixing, let the mixing container stand for 2–5 minutes to allow bubbles generated by stirring to float up naturally. Then, quickly sweep the surface with a heat gun (low temperature setting, 15–20cm away) or a butane torch to eliminate residual bubbles. Deep-pour epoxy resin has high inherent fluidity, so minor bubbles can float up on their own—avoid overheating to prevent interference with the resin’s curing reaction.

3、Key Techniques and Dosage Control

（1） Golden Rule for Dosage

The total dosage of pigments must be strictly controlled at 1%–5% of the total weight of the mixed resin (Parts A + B), with a maximum limit of 10%. Excessive pigments will disrupt the chemical balance of the resin, leading to slow curing, a tacky surface, insufficient hardness, and even shrinkage and cracking. A small amount of pigment is sufficient to achieve deep coloring—especially for liquid dyes, just 1–2 drops can create a pale color effect.

（2） Tips for Optimizing Color Effects

Transparent effect: Select liquid dyes and control the dosage at 1%–2%. Combined with transparent deep-pour epoxy resin, it can create a glass or gem-like texture, ideal for embedding specimens and metal parts.Pearlescent/metallic effect: Control the dosage of mica powder at 2%–3%, add it after pre-dispersion, and lightly sweep the surface with a heat gun after pouring to enhance the layered sense of luster.Artistic textures: When adding accents with alcohol inks, first pour a solid-color resin base. After the surface slightly gels, drop a small amount of ink, gently guide the texture with a toothpick, and then use a heat gun to assist in diffusion to prevent excessive ink penetration.Color calibration: The cured resin color may differ from its liquid state (usually slightly darker). Record the color comparison between liquid and cured states during the testing phase for precise control in bulk color mixing.

（3） Troubleshooting Common Issues

Color unevenness/streaks: Mostly caused by inadequate pigment dispersion or incomplete stirring. The solution is to enhance the pre-dispersion step, extend stirring time during mixing and scrape the dead corners of the container to avoid local pigment accumulation.Residual bubbles: In addition to static settling and heat defoaming, a small amount of specialized defoamer (dosage ≤ 0.5%) can be added during color mixing. However, the compatibility between the defoamer and pigments must be tested first to avoid color distortion.Color fading after curing: Choose UV-resistant pigments and avoid ordinary red and purple pigments that are prone to oxidation. If the finished product needs long-term exposure to sunlight, a UV protective coating can be applied.

4.Safety and Post-Procedure Notes

Wear gloves and a mask during color mixing and pouring to avoid direct skin contact with pigments. Meanwhile, keep the area well-ventilated to reduce inhalation of volatile fumes from resin and pigments. Pour the remaining colored resin within the working time (usually 30–40 minutes, subject to the resin instructions) to prevent operational failure due to resin thickening.

Maintain a clean and constant-temperature environment during the curing stage, and avoid vibration and extreme temperature differences. Deep-pour epoxy resin typically requires 24–72 hours for full curing. Do not touch or move the resin before complete curing to ensure stable color and a smooth surface.