Sikasil®-825
A low modulus, neutral cure silicone sealant
Sikasil®-825 is a low modulus, neutral cure, alkoxy, low odour silicone sealant that adheres to a wide range of both porous and non-porous surfaces without the need for priming.
- Excellent tooling and slow skinning properties for large scale construction and glazing applications.
- Excellent adhesion - adheres to most common surfaces including glass, metals, plastics and wood (painted or unpainted), uPVC and polycarbonate.
- Excellent external weathering properties (over many years exposure).
- High viscosity non-slump formula.
- Resistant to fumed hydrogen peroxide and fumed formaldehyde once fully cured.
Usage
- Perimeter pointing internally and externally around uPVC, wood and powder coated aluminium.
- Sealing and as an adhesive onto uPVC, plastic trims and components.
- Sealing soft metals such as lead, copper and zinc.
- Weather sealing and joint sealing to pre-formed panels and curtain walling, glazing sealing and draught proofing.
- Glass to glass and glass to aluminium sealing.
- Parapet and roof weather sealing applications.
- Ideal for precast concrete and masonry products, including brick, natural stone and terracotta.
- Suitable as an expansion joint sealant.
- Bedding and sealing of insulated glass units.
Advantages
- Excellent tooling and slow skinning properties for large scale construction and glazing applications.
- Excellent adhesion - adheres to most common surfaces including glass, metals, plastics and wood (painted or unpainted), uPVC and polycarbonate.
- Excellent external weathering properties (over many years exposure).
- High viscosity non-slump formula.
- Resistant to fumed hydrogen peroxide and fumed formaldehyde once fully cured.
Packaging
380 ml cartridge
600 ml foil pack
Colour
White, Black, Mid Grey, Dark Grey, Brick Red, Brown, Buff, Beige, Anthracite, Dark Anthracite RAL 7016, Magnolia, Portland Stone & Limestone White.
Product Details
APPROVALS / STANDARDS
- Certified to ISO11600 F25LM and G25LM.
- UKCA / CE marked under EN15651 for cold climate, façade, glazing and sanitary applications.
- ASTM C719 Class 35.
Chemical Base
Alkoxy silicone
Shelf Life
12 months from date of manufacture
Storage Conditions
Store in original unopened containers between +5 °C and +25 °C. Storage outside these parameters may dramatically reduce shelf life
Density
Colours: 1.33 - 1.37 g/cm3
Shore A Hardness
ca. 30
Modulus of Elasticity in Compression
0.35 MPa (ISO 11432, 100 %)
Shrinkage
<5 % (ISO 10563)
Elastic Recovery
>70 % (ISO 7389)
Tensile adhesion strength
0.5 MPa at break
Movement Capability
(ASTM C719) ±35 % (ISO 11600) ±25 %
Thermal Conductivity
0.10983 W/mK
Service Temperature
- 50 °C to + 150 °C
Joint Design
Maximum joint width 50 mm, max depth 50 % of joint width (from 10 mm)
Joint widths are calculated as in BS6213:
Width=(M x 100)/F + M
Where M = movement and F = movement accommodation Factor
For maximum movement accommodation, it is recommended that:
1. The sealant joint depth should be no less than 5 mm.
2. Joint depth should be 5 mm for joints up to 10 mm wide.
3. Joints above 10 mm in width should be half the width in depth up to 20 mm and minimum 10 mm for wider joints.
Joint depth may be adjusted to the correct size using JOINT BACKER ROD.
Elongation at break
>200 % (ISO 8339, +23 °C)
Application
Ambient Air Temperature
+ 5 °C to + 40 °C
Curing Time
mm/1 day approx 2
mm/3 days approx 6
mm/7 days approx 9
Skin Time
30 - 45 minutes (23 °C / 50 % RH)
Consumption
| Joint Size (mm) | Linear metres per 380ml |
| 5 x 5 | 15.10 |
| 5 x 10 | 7.60 |
| 10 x 15 | 2.52 |
| 10 x 20 | 1.90 |
| 12 x 25 | 1.28 |
SUBSTRATE PREPARATION
Sikasil®-825 does not require a primer on most common surfaces, although adhesion tests are recommended prior to full scale application. If the joint is likely to be immersed or if adhesion is poor (especially on porous surfaces) use Sika® Primer-3 N or Sika® Primer-115. To improve adhesion (if required) to non-porous surfaces, prime with Sika® Aktivator-205.
Surfaces must be clean, dry and free from dust, grease and other contaminants. Remove dust with compressed air. Degrease by using a solvent soaked pad, following by wiping with a clean cloth. The following cleaning procedure and materials are recommended:
| Glass | Degrease with alcohol or MEK |
| Aluminium, light alloys and stainless steel | Degrease with alcohol or MEK |
| Other Metals | Lightly abrade then degrease as above |
| Wood | Lightly abrade surface then remove dust |
| Plastics | Degrease using an agent recommended by plastics manufacturer |
| Concrete and other alkaline surfaces | Brush and remove dust |
| Polyester Powder Coated Aluminium (PPCA) | Sika® Cleaner P and Sika® Aktivator-205 |
CLEANING OF TOOLS
Uncured sealant - white spirit / Sika® Wonder Wipes.
Cured sealant - mechanically.