How do I measure and mix epoxy resin correctly?
Measuring Accurately
Most epoxy kits specify a ratio by volume (e.g., 1:1 or 2:1) or by weight. Use separate, clean measuring cups for resin and hardener to avoid cross-contamination. For small batches, a digital scale that reads to 0.1 grams is more accurate than volume cups, especially for ratios like 100:42. Always follow the manufacturer's ratio—do not adjust it to make the resin thinner or thicker.
If you measure by volume, pour to the same level line each time and check at eye level. For larger batches, mix at least 100 grams total to minimize measurement errors. Avoid mixing tiny batches under 30 grams unless you have a precise scale.
Mixing Technique
Pour the hardener into the resin (or as directed) and stir slowly for at least 3 minutes. Scrape the sides and bottom of the container frequently, and use a flat stick or spatula rather than a whisk to reduce bubbles. Mix until the liquid looks completely clear and streak-free—usually 3 to 5 minutes for a 100-gram batch.
After mixing, let the resin sit for a few minutes to let bubbles rise, or use a heat gun or torch quickly over the surface to pop them. Work in a warm room (75–80°F / 24–27°C) for best results; cold resin is thick and hard to mix thoroughly.
- Use separate cups for resin and hardener.
- Measure by weight for best accuracy, especially with non-1:1 ratios.
- Mix slowly for 3–5 minutes, scraping sides and bottom.
- Avoid whipping—it introduces bubbles.
- Let mixed resin rest before pouring to reduce bubbles.
- Work in a warm, dust-free area.
Common mistakes
- Eyeballing the ratio instead of measuring—this leads to uncured or sticky resin.
- Mixing too fast or for too short a time, leaving unmixed streaks that never cure properly.
- Using the same cup for both parts without cleaning, which can throw off the ratio.
