Quick Answer: Calculate volume (L × W × T), convert to fluid ounces, add 10-15% waste factor, then divide by 2 for 1:1 mix ratios. For a 24"×16"×0.25" coating: you need ~31 oz each of resin and hardener.
Professional Calculation Method
Follow these 4 precise steps used by professional resin workers
1Measure Your Project Dimensions
Accurately measure length, width, and desired thickness in consistent units (inches or centimeters).
Formula:
Volume = Length × Width × Thickness
Example:
For a 24" × 16" × 0.25" coating: 24 × 16 × 0.25 = 96 cubic inches
2Convert to Volume Units
Convert cubic inches to fluid ounces or cubic centimeters to milliliters.
Formula:
Cubic inches ÷ 1.805 = Fluid ounces
Example:
96 cubic inches ÷ 1.805 = 53.2 fluid ounces
3Add Waste Factor
Add 10-15% extra resin to account for mixing containers, spillage, and measurement variations.
Formula:
Total = Base Volume × 1.15
Example:
53.2 × 1.15 = 61.2 fluid ounces needed
4Account for Mix Ratio
Consider your resin's specific mix ratio (typically 1:1 or 2:1 resin to hardener).
Formula:
For 1:1 ratio: Total ÷ 2 = Amount of each component
Example:
61.2 ÷ 2 = 30.6 oz resin + 30.6 oz hardener
Project-Specific Calculation Guidelines
Project Type | Typical Thickness | Waste Factor | Special Notes |
---|---|---|---|
River Tables | 1.5" - 2" | 20% | Account for irregular river channel shape |
Coating/Finish | 1/8" - 1/4" | 10% | Even coverage, minimal waste |
Art Pieces | 1/2" - 1" | 15% | Variable thickness, moderate waste |
Casting Molds | Variable | 25% | Complex shapes, higher waste factor |
Professional Tips
Temperature Matters
Resin expands when warm. Calculate at your working temperature for accuracy.
Surface Preparation
Properly sealed surfaces require less resin. Porous wood may absorb 10-20% more.
Batch Mixing
For large projects, calculate total need but mix in smaller batches for better working time.
Common Calculation Mistakes to Avoid
❌ Don't Do This:
- • Forget the waste factor
- • Mix units (inches with centimeters)
- • Ignore surface porosity
- • Calculate at different temperatures
✅ Do This Instead:
- • Always add 10-15% extra
- • Use consistent measurement units
- • Test absorption on scrap pieces
- • Calculate at working temperature