Casting is a delicate process where specific guidelines must be followed to achieve high-quality and error-free results. Here’s a step-by-step guide on the key points to keep in mind during casting:
1. Surface Cleaning
Before starting the casting process, the surface where silicone will be poured must be thoroughly cleaned.
- Dust, dirt, or residues from previous castings may stick to the mold surface.
- This can lead to defects in the mold and undesirable outcomes.
2. Equipment Compatibility
When using platinum-based RTV2 silicone (Addition type):
- All equipment must be new or should not have been in contact with tin-based RTV2 silicones (Condensation type).
- Otherwise, curing will not occur on the mold's surface that comes into contact with the model.
3. Amount of Hardener - Excess Usage
The amount of hardener (catalyst) must be carefully measured, and excessive amounts should not be added.
- Too much hardener causes the silicone to thicken and form lumps during mixing or pouring.
- The silicone becomes too viscous to penetrate the model's details, leading to inaccurate replicas.
- Air bubbles will not have enough time to rise and pop, resulting in a mold with bubbles.
- Rapid curing weakens the bonds, reduces physical durability, and causes the silicone mold to stick to the model.
4. Amount of Hardener - Insufficient Usage
The amount of hardener must be carefully measured, and too little should not be added.
- Insufficient hardener causes the mold to cure very slowly or not at all.
- Incomplete curing can contaminate the model and require extensive cleaning.
- Weak bonds and low physical durability will make the mold prone to sticking to the model.
5. Mixing Process
Silicone and hardener should ideally be mixed at low-to-medium speed using a paint mixer.
- If no mechanical mixer is available, use a spatula to scrape the bottom and sides of the container while mixing.
- The mixing process should be completed within 1-2 minutes, and the casting process should begin immediately.
- Failure to mix properly will result in uneven curing, reducing efficiency.
6. Reducing Air Bubbles
Carefully control the amount of hardener and use a vacuum chamber to remove air bubbles.
- If a vacuum chamber is unavailable, vibration can be applied to minimize bubbles.
- Air bubbles must be kept to a minimum.
- Otherwise, the surface of the cast object will have imperfections, making it impossible to create a precise replica.
- Over time, bubble bursts in the mold will lead to cracks, shortening its lifespan.
7. Use of Mold Release Agents
Always use appropriate mold release agents.
- Without a release agent, the object may stick to the mold, causing the mold to tear or break during removal.
- Proper release agents ensure optimal performance and protect the mold.
Conclusion
For the best results when using RTV2 mold silicones, it’s essential to follow these guidelines. Should you need assistance during the casting process, feel free to contact our expert team for technical support.
Contact Information:
? +90 216 349 09 90