100% Silicone Sealant Industrial Grade
Technical specification for 100% silicone sealant used in Canadian fabrication, woodworking, and machining operations. Covers properties, sizing, machinability, defects, and storage guidelines.
Material Overview & Common Uses
100% silicone sealant is a one-part, moisture-curing, non-sag elastomeric sealant formulated from polydimethylsiloxane (PDMS) polymers. It contains no solvents, no isocyanates, and no acrylic modifiers, ensuring maximum flexibility and adhesion to non-porous substrates. In Canadian fabrication and woodworking environments, it is the standard for sealing joints in metal framing, glass assemblies, composite panels, and wood-to-metal transitions where movement is expected. It is also used for gasketing, vibration damping, and as a temporary or permanent adhesive in jig and fixture assembly. Its resistance to UV, ozone, and extreme temperatures (-60°C to 200°C) makes it suitable for both interior and exterior applications, including cold storage and heated production floors.
Core Technical Properties & Sizing
| Property | Value / Standard |
|---|---|
| Base Chemistry | 100% polydimethylsiloxane (PDMS), moisture-cure, neutral (oxime or alkoxy) system |
| Cure Mechanism | Moisture-activated; tack-free in 15–30 minutes at 23°C / 50% RH; full cure in 24–48 hours (3 mm depth) |
| Hardness (Shore A) | 20–30 (typical for general-purpose sealants) |
| Tensile Strength | 1.5–2.5 MPa (ASTM D412) |
| Elongation at Break | 400–600% (ASTM D412) |
| Service Temperature Range | -60°C to +200°C continuous; intermittent to 250°C |
| UV & Weather Resistance | Excellent; no significant degradation after 5000 hours QUV (ASTM G154) |
| Adhesion | Bonds to glass, aluminum, steel, stainless steel, PVC, polycarbonate, and most painted or coated surfaces without primer (primer recommended for porous substrates like concrete or wood) |
| Standard Packaging (Canadian Stock) | 310 mL cartridges (standard sausage pack), 600 mL sausage packs, 20 L pails, 200 L drums |
| Cartridge Dimensions | 310 mL – 51 mm diameter x 215 mm length (nominal) |
| Shelf Life | 12 months from date of manufacture when stored at 15–25°C in unopened containers |
| VOC Content | < 20 g/L (compliant with Canadian VOC regulations) |
| Color Options | Clear, white, black, grey, bronze, and custom RAL matches (minimum order quantities apply) |
Machinability, Tooling & Feeds
100% silicone sealant is not machined in the traditional sense, but it is applied and finished using pneumatic or manual caulking guns, extrusion nozzles, and profiling tools. For high-volume fabrication, automated dispensing systems (e.g., Nordson, Graco) with positive displacement pumps are used. Below are the standard tooling parameters and guidelines.
| Parameter | Specification / Guideline |
|---|---|
| Application Method | Pneumatic/manual caulking gun, automated dispenser (e.g., Nordson, Graco) |
| Nozzle Diameter | 1 mm – 10 mm |
| Application Pressure | 2 – 6 bar |
| Extrusion Rate | 5 – 20 g/s (bead size dependent) |
| Nozzle Travel Speed | 50 – 200 mm/s |
| Tooling Window | 5 – 10 minutes (before skin formation begins) |
| Tooling Lubricant | 1% dish soap solution or PTFE-coated tool |
| Rework (Uncured) | Wipe with mineral spirits |
| Rework (Cured) | Cut or abrade (e.g., razor blade, abrasive pad). Do not use solvents like acetone or MEK. |
Feeds and speeds are not applicable; instead, focus on extrusion rate and nozzle travel speed to achieve the desired bead geometry.
Common Defects & Quality Control
| Defect | Cause | Mitigation |
|---|---|---|
| Skin-over before tooling | High temperature / low humidity | Work faster or use a slower-cure variant |
| Bubbles or voids | Entrapped air during extrusion | De-aerate cartridge properly; ensure nozzle is fully immersed in the bead |
| Stringing or tailing | Nozzle lifted too quickly | Reduce travel speed or use a cut-off nozzle |
| Poor adhesion | Oily or wet substrates | Clean with isopropyl alcohol (99%) and ensure surface is dry |
| Cracking after cure | Excessive joint movement beyond design limits (>25% of joint width) | Verify joint design per ASTM C920 |
| Discoloration | Contact with certain plastics (e.g., polycarbonate) or chemicals | Test compatibility before full production |
Quality control checks: Measure bead dimensions with a profile gauge, perform a 90° peel test on a sample joint, and verify cure time with a tack-free test (ASTM C679).
Storage, Handling & Racking Guidelines
| Guideline | Specification |
|---|---|
| Storage Temperature | 15°C – 25°C (cool, dry environment) |
| Max Temperature / Environment | Avoid > 30°C and direct sunlight |
| Freezing | Do not freeze; if frozen, thaw at room temperature for 24 hours and test before use |
| Racking | Use sturdy shelving rated for weight (310 mL cartridge ~0.4 kg; 20 L pail ~22 kg) |
| Stock Rotation | First-in, first-out (FIFO) basis |
| Opened Cartridges | Use within 24 hours or seal with a cap and store nozzle-down to prevent skin formation |
| Bulk Pails | Use a pump or scoop; reseal tightly after each use |
| Disposal (Cured) | Dispose of as non-hazardous waste |
| Disposal (Uncured) | May be classified as hazardous depending on local regulations (check with your waste hauler) |