A high modulus, one part acetoxy curing sealant conforming to ISO 11600 F & G; Class 20HM. In its uncured state 5024A is a thixotropic paste which can be applied over a wide range of temperatures with no risk of slumping from normal joint widths.The paste cures rapidly on exposure to moist air to form a tough - rubber seal capable of repeated extension and compression during service with excellent resistance to:
- Ageing
- Shrinkage
- Cracking and Discolouration
5024A offers good adhesion to various non-porous substrates such as glass - glazed ceramic tiles and metals (including Aluminium). 5024A is recommended as a general purpose sealing and bonding agent and can be used to produce formed-in-place gaskets or as a space-filling rubber adhesive.
Joint Preparation
The joint should first be checked to ensure that the dimensions comply with the drawing. The joint faces to be bonded must be free from:
- Frost
- Loose debris
- Dust
- Oil and Grease
Non-porous surfaces should be cleaned with non-oily solvent (e.g. Ambersil Amberklene FE10). Flaking paint or lacquer should be removed.
Joint Design
The mean joint width should not be less than 4 times the total expected movement. For optimum movement accommodation:
- (a) the joint depth or width should not be less than 3mm
- (b) the joint depth should be 3mm up to a joint width of 6mm
- (c) above joint widths of 6mm the joint depth should equal half the width
Back-up Material
Back-up strips can be used to control the joint depth and minimise adhesion to the back of the joint. Expanded polyethylene in rectangular or rod form is recommended but polyurethane and neoprene can also be used. Some rubbers contain plasticises which may bleed into the silicone sealant and discolour it. A test on these backing materials should be made to ensure staining does not occur.
Uncured Compount
- Appearance: Smooth easily extruded translucent paste
- Sag and Flow: Nil
- Specific Gravity: 1.03
- Skin over time: 8 to 20 minutes
- Cure rate: 3 mm - 1 day, 5 mm - 3 days
Cured Compound
Results are based on a 3mm sheet cured at ambient conditions for 7 days.
- Hardness: 18 Shore A - minimum
- Elongation at break: 450% minimum
- Tensile Strength: 1.55 MPa - minimum
- Temperature Resistance: -50°C to +204°C (Short term 218°C)
Limitations
Silicone Adhesive Sealant 5024A is not recommended in situations where abrasion and physical abuse are encountered. It should not be applied to:
- Bituminous substrates
- Substrates based on natural rubber
- Chloroprene or EPDM
- Materials that bleed oils
- plasticises or solvents
Sealant 5024A is not recommended for bonding to porous substrates such as stone or marble or surfaces which could react with acetic acid - e.g. lime based cements and mortars and copper-based or Zinc coated (galvanised) metals. 5024A is unsuitable for aquarium applications.
Storage
Store the sealant in a cool dry place out of direct sunlight at temperatures not exceeding 30°C. Under these conditions the sealant in its original unopened package - has a storage life of 18 months.
Flammability
Flash point greater than 100°C (closed cup). Burns at high temperatures to form an ash without dripping.
Caution: On direct contact uncured sealant irritates the eyes. In case of contact - remove sealant, flush eyes with plenty of water and seek medical attention.