Finding the right RTV silicone rubber for mold making means balancing detail reproduction, cure time, ease of use, and durability. This guide highlights five popular, user-friendly options that perform well across resin, wax, soap, and craft projects. Each product is platinum-cured, offers easy 1:1 mixing, and provides reliable demolding with strong tear resistance. Read on to compare features, applications, and practical considerations for choosing the best silicone rubber for your molds.
| Product | Volume | Key Strength |
|---|---|---|
| LET’S RESIN Silicone Mold Making Kit — 140 oz | 140 oz / 1 gal | High volume, clear and flexible |
| SPRESIN Cast-A-Mold 25T RTV — 0.5 gal | 0.5 gal | Premium quality, versatile casting |
| SHORE RESIN 66oz Silicone Mold Making Kit | 66 oz | 15A hardness, detailed replication |
| JHKL RESIN Silicone Mold Making Kit — 1 gal | 1 gallon | Beginner-friendly, low viscosity |
| Nicpro 80oz Silicone Mold Making Kit — 80 oz | 80 oz | Food-grade safe, 30A hardness option |
Note: The vendors list a 1:1 mix ratio by weight for all kits, with varying cure times depending on size and thickness. All options are suitable for resin, wax, soap, and craft molds, and many offer additional accessories like gloves, sticks, and cups to streamline production.
LET’S RESIN 140 Oz Silicone Mold Making Kit
The LET’S RESIN kit uses platinum-cured silicone, delivering non-toxic, odor-free material that remains flexible and clear. It supports color customization with mica powders and uses a straightforward 1:1 mix by weight. Working time at room temperature is about five minutes, with bubbles reducing automatically within roughly two hours. Complete cure typically ranges from six to twelve hours depending on mold size and thickness. If the surface feels sticky, longer cure times may be needed.
Key details from features
- Translucent, flexible silicone with low odor
- 1:1 A:B mix; five-minute working time
- No vacuum degassing required
- 6–12 hour cure window (size dependent)
LET’S RESIN 20.46oz Translucent Silicone Kit
This smaller translucent silicone kit also uses platinum-cured, non-toxic rubber. It’s designed for ease of use with a 1:1 weight mix and a five-minute pot life. The kit prioritizes bubble reduction without vacuum degassing and cures within about 4 hours, depending on mold specifications. It’s well-suited for hobbyists making multiple, smaller molds or experimenting with color additives.
Key details from features
- Non-toxic, odor-free, clear material
- 1:1 ratio; five-minute working time
- Bubble management without degassing
- Four-hour cure window with mold size variation
Nicpro 80 Oz Silicone Kit — 80 oz
Nicpro’s 80 oz kit features a 1:1 mix by weight, with a 5-minute working time and a 3–5 hour cure window at room temperature. It uses platinum-grade RTV-2 silicone and emphasizes food and skin-safe properties, making it suitable for a range of crafts, including candy or chocolate molds (with caution for food contact scenarios). The kit includes gloves, sticks, cups, and accessories for a smoother workflow. Avoid UV resin as it may not cure in this formula.
Key details from features
- Food-safe, odorless platinum silicone
- 1:1 mixing; 3–5 hour cure at room temp
- Includes accessories for immediate use
- Not compatible with UV resin curing
JHKL RESIN 1 Gallon Silicone Kit
JHKL RESIN’s kit is designed for beginner-friendly use with a 1:1 ratio and low viscosity for easy mixing. The platinum silicone ensures high elasticity and fine detail replication, making it suitable for both 3D resin molds and flat molds. While it provides good de-molding, the kit may benefit from degassing if a vacuum champion is available. Curing time is contingent on mold size and thickness, with promising results for repeated use due to its durable silicone composition.
Key details from features
- 1:1 mix by weight or volume
- 15A hardness for detailed molds
- Low viscosity; beginner-friendly
- Suitable for repeated use and varied projects
Nicpro 80oz Kit — 2x40oz Bottles
This Nicpro offering pairs two 40 oz bottles for a total of 80 oz with a 1:1 ratio, five-minute working time, and a 3–5 hour cure window at room temperature. The kit emphasizes food-grade safety and low odor, making it versatile for arts, crafts, and confections. Accessories include gloves and mixing tools for immediate use. Avoid UV resin as a cure method for this formulation.
Key details from features
- Platinum RTV-2 silicone, 30A or 15A variants
- 1:1 mixing; quick working time
- Accessories included for convenience
- High durability and tear resistance for repeated use
Buying Guide: How To Choose The Right RTV Silicone Rubber
When selecting RTV silicone rubber for mold making, consider the following:
- Hardness and elasticity: A 15A-30A range suits most resin and craft molds, balancing detail capture with easy demolding. Higher hardness (closer to 30A) tends to be less flexible but more tear-resistant.
- Cure time and working time: Shorter working times speed up production but can raise the risk of air bubbles. Look for products with bubble management or degassing options if you’re molding fine details.
- Mix ratio and viscosity: A 1:1 mix is simplest, especially for beginners. Low viscosity helps air bubbles escape and reduces runny pours, improving edge fidelity.
- Volume and scalability: For large projects or multiple molds, higher volumes (e.g., 1 gallon) reduce stocking frequency. For starter projects, smaller kits reduce waste and cost.
- Food safety and skin contact: If molds will touch edible items or skin, choose food-grade options and verify resin compatibility. Some kits note food-safe claims, but always confirm with your end-use scenario.
- Compatibility with resins and additives: Most silicone rubbers work well with epoxy, polyurethane, wax, and concrete. If you plan to add mica powders or pigments, ensure pigment compatibility.
- Degassing options: Vacuum chambers or pressure pots can improve detail by removing air bubbles, particularly for intricate molds. Many entry-level kits perform well without degassing.
- Durability and reuse: Consider molds designed for repeated cycles if you need to produce multiple items. Platinum-cured rubbers generally offer better longevity than tin-cured options.
For best results, follow the manufacturer’s mixing instructions precisely, stir thoroughly to reduce air pockets, and allow adequate cure time in a stable environment. Store unmolded silicone away from direct heat and sunlight to preserve flexibility and color clarity.