Resin art has taken off in Indian homes and small studios, from coasters sold on Instagram to river tables in Jaipur workshops. Nearly every beginner loses at least one piece to a sticky surface or a cloud of bubbles. Most epoxy resin mistakes come from measurement, mixing or temperature. Here are the common ones, why they happen, and what to do differently.
1. Sticky or soft resin that never cures
Cause: the wrong ratio, ratio by volume when the label said by weight, or not mixing long enough. Fix: read whether the ratio is by volume (2:1, 1:1) or by weight (for example 100:45). Mix slowly for the full time on the label, usually 3–5 minutes, scraping the sides and bottom. Soft spots can't be rescued by adding more hardener later; scrape them off and re-pour.
2. Too many bubbles
Cause: whipping while mixing, cold resin that is too thick, or porous materials (wood, dried flowers) releasing air. Fix: stir slowly, warm the bottles in a bowl of warm water before mixing, seal wood with a thin coat first, and pass a heat gun or torch briefly over the surface after pouring.
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3. Cracks, smoke or a hot cup
Cause: pouring too thick for the product. Epoxy cures by an exothermic reaction; a deep pour of coating resin can overheat. Fix: keep coating resin to about 3–6 mm per layer, use deep-pour resin for thick castings, and pour in layers where the label's maximum depth is less than the mould's depth.
Why does my resin cure much faster in summer?
Heat speeds up the reaction. In a 35 °C room the working time can be roughly half of what the label states. Mix smaller batches, work in the cooler morning, and keep the mixed cup in a shallow tray rather than a tall cup.
4. Yellowing
Cause: UV exposure, overheating during cure, or a resin without UV stabilisers. Fix: choose a UV-resistant resin for pieces near windows, avoid over-thick pours, and keep finished work out of direct sun.
5. Running out mid-pour
Cause: estimating by eye. Fix: calculate the volume first. A rectangle in centimetres gives millilitres directly: length × width × depth. A 25 × 25 cm coaster set at 0.6 cm deep needs 375 ml; add about 10% for the cup and stirrer.
Volume (ml) = L × W × D (cm) Round mould = 3.1416 × r² × D Weight (g) ≈ ml × 1.1
6. Skipping safety
- Wear nitrile gloves; uncured epoxy can cause skin sensitisation over time.
- Work with ventilation and keep resin away from food areas and children.
- Use a respirator when sanding cured resin; the dust is fine and irritating.
Epoxy resin mistakes at a glance
| Symptom | Usual cause | Fix next time |
|---|---|---|
| Sticky or soft | Wrong ratio or under-mixing | Follow the label (volume vs weight); mix 3–5 minutes |
| Bubbles | Fast stirring, cold resin, porous inserts | Warm bottles, stir slowly, seal wood, heat gun |
| Cracks or smoke | Pour too deep | Respect the maximum depth; pour in layers |
| Yellowing | UV or overheating | UV-resistant resin; keep out of direct sun |
| Ran out mid-pour | Guessed quantity | Calculate L × W × D in cm; add 10% |
The resin calculator gives the total volume for rectangular, round and other moulds, splits it into part A and part B for 1:1, 2:1 or 3:1 kits, and converts to grams.
Frequently asked questions
Why is my epoxy resin still sticky?
Usually a wrong ratio, measuring by volume when the kit needs weight, or under-mixing.
How do I stop bubbles in resin?
Warm the bottles, stir slowly, seal porous materials first and pass a heat gun briefly over the surface.
Why did my resin crack?
It was poured too thick for the product and overheated while curing.
How much resin do I need?
Length × width × depth in cm gives ml; add about 10% extra.
Does heat affect epoxy resin?
Yes. High room temperatures shorten working time significantly.
Keep reading
- Resin Calculator: the free tool this guide explains.
- All construction calculators
- RHS vs SHS: Rectangular or Square Hollow Section, Which to Use
Sources: epoxy manufacturers' technical data sheets (mix ratio, pot life, maximum pour depth); 1 cm³ = 1 ml.