RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30) for Rectangular Mold Box Calculator
Pre-loads specific gravity (1.07) and 1:1 mix ratio to calculate exact Part A & Part B weights with cup scraping buffer.
A standard Rectangular Mold Box (15 × 10 × 6 cm minus 150 cm³ master) requires 867g (30.57 oz / 1.91 lbs) of RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30). Mix 433.4g Part A with 433.4g Part B (8% buffer included).
Casting Material & Volume Mode
Pre-loads specific gravity and 1:1 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 1.07
Ratio part: 1
Ratio part: 1
Net volume before buffer
Order RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30) Kit
High-tear strength RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30) with verified 1:1 ratio. Ideal for bubble-free casting.
RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30) 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 |
|---|---|---|---|---|
| RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30)ACTIVE | 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 |
| Table Top & Art Epoxy (1:1 Ratio) | 1.08 | 1:1 (weight) | 25 min | 12 hrs |
Step-by-Step Mix Ratio Derivation: RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30)
How displacement volume, specific gravity, and ratio split combine into final scale weights.
Calculates the empty fluid cavity by taking the gross 900 cm³ box containment volume and deducting the 150 cm³ displaced by the master model.
Multiplies fluid volume by the specific gravity of RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30) (1.07 g/cm³) plus an 8% buffer for cup scraping and pouring loss.
Distributes batch mass according to the exact 1:1 ratio by weight.
Engineering Specifications & Troubleshooting Guide: RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30)
Factory-tested parameters, common failure modes, and workbench best practices.
- Platinum cure silicone has near-zero shrinkage (<0.1%) and lasts for decades without weeping oils.
- Beware of cure inhibition: sulfur clays, latex gloves, condensation tin silicones, and uncured UV 3D resin will inhibit curing completely.
- Degas in a vacuum chamber at 29 inHg for 2-3 minutes, or pour in a long, thin stream from 18 inches above to pop micro-bubbles naturally.
Wearing latex gloves while handling molds; the sulfur vulcanizers in latex poison platinum catalysts, leaving sticky uncured slime.
Frequently Asked Questions: RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30)
Mix ratios, degas guidelines, cure times, and mold making tips.
Q1What is the mix ratio of RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30)?
Q2How much RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30) do I need for a Rectangular Mold Box?
Q3How long before I can demold RTV-2 Platinum Silicone (Smooth-On Mold Star 15/30)?
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