Clear Water-Resin Polyurethane (Clear Flex 50) for Hemisphere / Dome Mold Calculator
Pre-loads specific gravity (1.08) and 1:2 mix ratio to calculate exact Part A & Part B weights with cup scraping buffer.
A standard Hemisphere / Dome Mold (Ø10 cm minus 150 cm³ master) requires 130g (4.6 oz / 0.29 lbs) of Clear Water-Resin Polyurethane (Clear Flex 50). Mix 43.5g Part A with 86.9g Part B (8% buffer included).
Casting Material & Volume Mode
Pre-loads specific gravity and 1:2 ratio by weight.
Geometry determines the container-volume formula. Use water displacement when the cavity is irregular.
Volume displaced by your master object inside the box.
Compensates for resin clinging to mixing paddles and cup walls (8% recommended).
Includes 8% waste buffer at SG 1.08
Ratio part: 1
Ratio part: 2
Net volume before buffer
Order Clear Water-Resin Polyurethane (Clear Flex 50) Kit
High-tear strength Clear Water-Resin Polyurethane (Clear Flex 50) with verified 1:2 ratio. Ideal for bubble-free casting.
Clear Water-Resin Polyurethane (Clear Flex 50) vs Alternative Casting Compounds
Compare specific gravities, mix ratios, working times, and cure speeds across casting compounds.
| Material / Specification | Specific Gravity | Mix Ratio | Pot Life | Demold Time |
|---|---|---|---|---|
| Clear Water-Resin Polyurethane (Clear Flex 50)ACTIVE | 1.08 | 1:2 (weight) | 20 min | 16 hrs |
| RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30) | 1.07 | 1:1 (weight) | 30 min | 6 hrs |
| RTV-2 Tin Cure Silicone (Condensation Cure) | 1.12 | 10:1 (weight) | 45 min | 12 hrs |
| Jesmonite AC100 (Eco-Resin) | 1.75 | 2.5:1 (weight) | 12 min | 2 hrs |
| Jesmonite AC730 (Stone Casting) | 1.85 | 5:1 (weight) | 15 min | 4 hrs |
| Deep Pour River Epoxy (2:1 Ratio) | 1.11 | 2:1 (weight) | 90 min | 48 hrs |
Step-by-Step Mix Ratio Derivation: Clear Water-Resin Polyurethane (Clear Flex 50)
How displacement volume, specific gravity, and ratio split combine into final scale weights.
Calculates the empty fluid cavity by taking the gross 261.8 cm³ hemisphere containment volume and deducting the 150 cm³ displaced by the master model.
Multiplies fluid volume by the specific gravity of Clear Water-Resin Polyurethane (Clear Flex 50) (1.08 g/cm³) plus an 8% buffer for cup scraping and pouring loss.
Distributes batch mass according to the exact 1:2 ratio by weight.
Engineering Specifications & Troubleshooting Guide: Clear Water-Resin Polyurethane (Clear Flex 50)
Factory-tested parameters, common failure modes, and workbench best practices.
- Water-clear flexible urethane elastomer with extreme UV resistance and non-yellowing characteristics.
- Requires pressure casting at 60 PSI to crush micro-bubbles for optical transparency.
- Always pre-heat silicone molds to 40°C before casting to prevent surface cure inhibition.
Casting without a pressure pot; clear urethanes will cure with a cloudy, champagne-bubble haze without pressure.
Frequently Asked Questions: Clear Water-Resin Polyurethane (Clear Flex 50)
Mix ratios, degas guidelines, cure times, and mold making tips.
Q1What is the mix ratio of Clear Water-Resin Polyurethane (Clear Flex 50)?
Q2How much Clear Water-Resin Polyurethane (Clear Flex 50) do I need for a Hemisphere / Dome Mold?
Q3How long before I can demold Clear Water-Resin Polyurethane (Clear Flex 50)?
Next Step In Your Project (Companion Fabrication Tools)
Pair your current build with companion engineering calculators: