Short answer: cloudiness usually comes from tiny bubbles (mixing too fast or cold resin), moisture (humid room, wet molds or inclusions), cold resin or room, an off ratio, or, after sanding, fine scratches that scatter light. Warm the bottles, mix slowly, keep everything dry and measure exactly. A sanded surface turns clear again with finer grits and polish or a thin top coat.
| Scale | 0.01 g digital scale → | Accurate ratio |
| Torch | Heat gun / butane torch for bubbles → | Surface bubbles |
| Gloves | Nitrile gloves & organic-vapor respirator → | Keep moisture & oils out |
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| When | Likely cause | Fix |
|---|---|---|
| While mixing | Micro-bubbles, cold resin | Warm bottles in a water bath, stir slowly, let it rest (bubble fixes) |
| After curing | Moisture, humidity, cold room, ratio | Dry molds and inclusions, stay within label temp and humidity, measure by the label |
| After sanding | Scratches | Sand through finer grits and polish, or brush a thin coat |
| On one side only | Mold surface or contact with a cold/damp surface | Check the mold, pour on a warm, dry surface |
Planning in a cold room? See curing resin in the cold. Comparing products? Resin vs epoxy.
Common causes are moisture (humid air, damp molds or inclusions), a cold cure, or an off ratio. Keep materials dry and within the label's temperature range.
Usually micro-bubbles from cold resin or fast stirring. Warm the bottles and mix slowly; it often clears as bubbles rise.
Continue through finer sandpaper grits and polish, or apply a thin top coat of resin to restore clarity.
More tools: resin calculator · mix ratio by weight · cure time · mold volume · tabletop coating · pouring too thick
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