How Much Resin for 3 Inch Depth
A 3 inch deep epoxy pour is a significant undertaking — common for thick slab river tables, deep bookend molds, and large decorative castings. At this depth, volume is substantial and product selection is critical. This page covers exact volume estimates and the safety requirements for 3 inch pours.
Enter your exact dimensions and depth to get a precise resin volume in fluid ounces or gallons.
Use the Volume Calculator →The Formula
1.805 converts cubic inches to fluid ounces. Add 10% waste to the result.
Example: a river channel 8 inches wide × 48 inches long at 3 inches deep:
8 × 48 × 3 = 1,152 cubic inches ÷ 1.805 = ~639 fl oz (~5 gallons)
Volume Table — Common Areas at 3 Inch Depth
| Area (L × W) | Volume (fl oz) | Volume (gallons) |
|---|---|---|
| 6 in × 12 in | ~120 fl oz | ~0.94 gal |
| 6 in × 24 in | ~239 fl oz | ~1.87 gal |
| 6 in × 48 in | ~479 fl oz | ~3.75 gal |
| 8 in × 48 in | ~639 fl oz | ~5 gal |
| 10 in × 72 in | ~1,196 fl oz | ~9.3 gal |
| 12 in × 12 in | ~239 fl oz | ~1.87 gal |
| 12 in × 24 in | ~479 fl oz | ~3.75 gal |
| 12 in × 48 in | ~958 fl oz | ~7.5 gal |
Add 10% to all volumes above for cup residue, mixing loss, and fill variance in irregular mold shapes.
Epoxy Type and Safety for 3 Inch Pours
Only use deep-pour casting resin rated for 3+ inches. Pouring 3 inches with coating or tabletop epoxy creates a fire hazard — the exothermic reaction in a thick, confined pour generates enough heat to crack the mold, yellow the resin, and in extreme cases start a fire.
If your deep-pour resin is only rated to 2 inches, split the 3 inch total into two pours:
- Pour 1: 1.5 inches — allow to fully cure (48–72 hours)
- Pour 2: 1.5 inches — pour on top of the fully cured first layer
The seam between layers is essentially invisible in clear pours. See: how many layers of epoxy for guidance on multi-layer pours.
Cure Time at 3 Inch Depth
Deep-pour resins cure more slowly than surface coatings. At 3 inches:
- Initial gel: 18–36 hours depending on temperature and product
- Demold: 48–72 hours minimum for most deep-pour resins
- Full cure: 7–14 days before sanding, cutting, or applying a surface coat
Warmer rooms accelerate cure but also increase internal heat — stay between 70–80°F for 3 inch pours.
Frequently Asked Questions
How much resin do I need for a 3 inch deep pour?
Multiply your area (length × width in inches) by 3, then divide by 1.805 to get fluid ounces. For an 8×48 inch channel at 3 inches: 1,152 ÷ 1.805 ≈ 639 fl oz (~5 gallons). Add 10% waste. Use the volume calculator for any custom size.
Can any epoxy be poured at 3 inches in one shot?
Only deep-pour casting resins rated for 3 or more inches per layer. If your product is only rated to 2 inches, pour in two 1.5-inch layers with full cure in between. Never use tabletop or coating epoxy for 3 inch pours — overheating and cracking will result.