Momentive RTV630 Two‑Component Room‑Temperature‑Vulcanizing Silicone Rubber

Momentive RTV630 is a blue two‑component silicone rubber compound manufactured by Momentive, which cures at room temperature into high‑strength silicone rubber. Supplied as a matched kit, it consists of base (Part A) and curing agent (Part B) with a 10:1 weight‑based mixing ratio. The mixed material delivers moderate pourable viscosity for producing thin‑walled, long‑service‑life molds. Featuring high tear resistance and inherent release performance, it can precisely replicate complex and fine structural details. It is also suitable for prototype manufacturing, tooling for epoxy casting, rubber rolls, as well as potting of vibration‑resistant electrical circuits.

• 10:1 weight mixing ratio, compatible with both manual mixing and automatic dispensing equipment
• Good self‑leveling property to achieve precise reproduction of fine model details
• Solvent‑free formulation
• Long working time at room temperature, enabling casting and potting of large‑size components
• Cure rate can be accelerated by applying heat
• Capable of deep‑section curing and curing inside closed assemblies
• No cure by‑products generated during cross‑linking
• Low cure shrinkage

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1. Mold fabrication for intricate castings and precise replicas; thin‑wall durable molds
2. Fabrication of hand‑craft models and prototype parts
3. Production tooling for epoxy casting and manufacturing of rubber rolls
4. Potting and encapsulation for electrical circuits requiring superior vibration‑resistant performance

1. Mixing Ratio: Strictly follow the weight ratio A:B = 10:1. Always use Part A and Part B from the same kit. Select a mixing container with 4‑5 times the volume of the target material. Thoroughly scrape the wall and bottom of the container to obtain a homogeneous mixture.
2. Degassing: Apply vacuum degassing at approximately 25 mmHg after mixing. Maintain vacuum for around 2 minutes after surface frothing disappears. Secondary degassing after pouring is recommended for complex assemblies.
3. Curing Schedule: The material can be demolded and handled after 24 hours curing at 25℃. To obtain optimal final properties, cure for 2 days at room temperature or adopt heat‑accelerated curing. Reference curing duration: 7 days @25℃; 4 h @65℃; 1 h @100℃; 15 min @150℃.
4. Bonding: For adhesion to non‑silicone substrates, thoroughly clean the substrate. Apply SS4155 silicone primer in a uniform thin film and allow at least 1 hour of air‑drying before pouring mixed Momentive RTV630 compound.
5. Cure Inhibition Risk: Butyl rubber, sulfur‑containing substances, amines and certain materials may cause cure inhibition. Always perform a small‑scale patch compatibility test prior to full‑scale pouring work.

Q1: Can I mix Momentive RTV630 at a 10:1 ratio by volume? A: No. Mixing must be completed strictly by 10:1 weight ratio. Volume‑based mixing will result in incomplete curing, degraded physical properties and abnormal pot life. Components must be weighed before mixing.

Q2: Why does the silicone remain gummy or incompletely cured after pouring? A: Root causes may include: ①Incorrect A/B mixing ratio; ②Cure‑inhibiting contaminants (sulfur, amines, butyl rubber, etc.) on the substrate surface; ③Part A and Part B sourced from different kits; ④Low ambient temperature. Run a small patch test for fault diagnosis.

Q3: Can finished parts be directly put into service after 24‑hour room‑temperature curing? A: 24‑hour room‑temperature curing only allows demolding and manual handling. To achieve complete mechanical and electrical performance, cure for at least 2 days at room temperature or implement heat curing. Thicker sections require longer curing cycles.

Q4: Will Momentive RTV630 bond directly to metal or plastic substrates? A: Direct adhesion to non‑silicone substrates is not available. SS4155 primer is mandatory. Degrease and clean the substrate thoroughly; ensure full air‑drying of the primer before pouring silicone.

Q5: What are the safety precautions for Part B curing agent? A: Momentive RTV630‑B curing agent shall avoid contact with acidic, alkaline or oxidizing materials, as such contact may generate flammable hydrogen gas. Refer to the complete SDS prior to material handling.

Q6: What is the maximum curable cross‑section thickness? A: This product supports deep‑section curing and can cure within closed assemblies. Practical thickness is subject to curing temperature and material mass. Heat curing is preferred for large and thick components.

Q7: What are the storage requirements? A: Please refer to the original SDS and Certificate of Analysis. Store in a cool, well‑ventilated environment away from excessive heat. Keep Part A and Part B sealed in original packaging.