Two-component RTV silicone
Frequently asked questions
Can Two-component RTV silicone be laser cut?
No: Two-component RTV silicone is not suitable for laser cutting. However, it releases toxic fumes — machining is not recommended.
Can Two-component RTV silicone be CNC machined?
No: Two-component RTV silicone is not suitable for CNC milling.
Is Two-component RTV silicone food safe?
No, Two-component RTV silicone is not considered food safe.
Physical properties
| Density | 1000.0–1400.0 kg/m³ |
|---|---|
| Tensile strength | 6.0 MPa |
| Thermal expansion | 300.0 µm/m·K |
| Moisture absorption | Negligible |
Laser processing
Thermal decomposition of RTV silicone releases crystalline silica (SiO2) dust, highly abrasive to laser lenses and mirrors and irritating to the respiratory tract with repeated exposure. Chronic inhalation of fine silica is a well-known occupational hazard (silicosis). In addition to operator toxicity, the damage to optics can render the machine unusable within minutes.
CO₂: Strongly advised against. Silicone decomposition under the laser beam generates extremely fine white powder of silicon dioxide (SiO2), a very hard mineral that deposits on the machine optics, scratching them irreversibly within minutes of exposure.
Diode: Strongly advised against for the same reasons as the CO2 laser.
Fiber: Not applicable.
CNC / milling processing
Elastomer: cannot be milled or cut with CNC in a controlled manner. The material deforms elastically around the bit without removing useful chips.
Post-processing
Sanding: Not sandable. Flash and imperfections must be removed exclusively with a scalpel or sharp blade.
Primer: Nothing chemically bonds to cured silicone without a specific silicone adhesive primer.
Gluing: Repairable or bondable only with fresh silicone of the same type or with one-component silicone sealant. Specific silicone adhesive primers (e.g., Dow Corning 1205) improve adhesion on rigid substrates.
Over time: Excellent long-term stability: resistant to UV, ozone, moisture, extreme thermal cycling (–50 °C to +200 °C), and most common chemical agents. This is the defining characteristic of silicone as a material class.
Common defects
- Cure inhibition by sulphur (plasticine, modelling clay), latex, or not-fully-cured cyanoacrylates (for platinum silicone)
- Variable dimensional shrinkage depending on chemistry (addition: <0.5%; condensation: 1–3%)
- Catalyst segregation in poorly mixed systems — uncured spots, sticky surface
Safety
Recommended PPE: gloves_nitrile, mask_p2
Cured RTV silicone is essentially inert. During mixing and pouring in the liquid state, the catalysts (stannous for condensation, platinum complexes for addition) require adequate ventilation and nitrile gloves. The main hazard is thermal processing: do not heat, do not laser-process.
Availability and formats
Commercial formats: two-part A+B pourable liquid kit, two-part paste for industrial applications, shore A from 10 (very soft) to 60 (rigid for gaskets)
Related materials
Sources
- Dow Corning — Silastic RTV Silicone Rubbers Technical Manual
- Momentive — RTV615 Technical Data Sheet
- Smooth-On — Technical Overview: Addition Cure vs Condensation Cure Silicones
Information on compatibility, processing parameters and safety is purely indicative. MakerSpecs accepts no liability for damage to persons or property arising from the use of this data. Always check the safety rules and the manufacturer's official manuals before carrying out any processing.