Fire Mastic

Product Options

Gyprock Fire Mastic is available in a 600ml sausage and has a shelf life of 12 months from date of manufacture.

For product availability and to place an order, contact your nearest supplier.

Physical & Chemical Properties

Product Manufacture

FireMastic is manufactured for CSR Gyprock in Australia to stringent product specifications.

Storage 

Store unopened sausages below 30°C in a cool dry place away from direct sunlight. Opened sausages may skin and form a lump near the opening. Discard any lumps or skin and remaining product can be used.

Health and Safety

Safety Data Sheets are available on the Gyprock web site. They are important documents in the construction industry and assist in the continuing focus on occupational health and safety on and off work sites.

Surface Preparation

Ensure substrate surfaces are clean, sound, dry and free of oil, grease and surface contaminants such as dust, loose particles, release agents, silicone and water repellents.
This is particularly important regarding highly porous surfaces such as aerated concrete or cut edges of plasterboard. In circumstances where it is difficult to ensure completely dust free surfaces applying by brush a 1:1 solution of Fire Mastic and water as a primer will assist to improve the integrity of the substrate. Areas adjacent to joints may be masked to provide a neat finish. Masking should be removed immediately after tooling

Application

Apply Fire Mastic in ambient conditions between 5 and 35 degrees centigrade. Higher temperatures should be avoided to prevent the possibility of bubbling of the
sealant due to rapid moisture evaporation. Do not apply below 5 degrees centigrade.
Fill joint with trowel or caulking gun, then tool off with a spatula and clean off excess with a damp cloth.

Curing

Protect from water for at least 24 hours until a suitable skin has cured (will require significantly longer at temperatures below 15 degrees centigrade). Some shrinkage is normal during curing, and should be anticipated when measuring joints.

Clean up

After applying Fire Mastic, clean all tools and metal surfaces with warm water while the sealant is still wet. Cured sealant will need to be removed mechanically.

Painting

Firemastic sealant is suitable for painting when fully cured. To avoid paint cracking issue, Firemastic should be cured for at least 24 hours, longer under adverse drying conditions (cooler, high humidity) before painting where possible. In standard conditions (25 °C or higher) Firemastic may be painted after 6 hours, however, care should be taken to ensure a flexible acrylic coating is used and that a firm skin has developed.

Limitations

• Do not apply to wet surfaces, contaminated, dusty, loose substrate surfaces.
• Firemastic sealant may be used both for interior and exterior sealing, but not recommended for use in water retaining structures or water may be pooling.
• Firemastic is not recommended in exterior applications where non-porous substrates are to be sealed.
• Firemastic sealant has good servicing characteristics when unprotected in internal applications.
• For external use, Firemastic sealant must be protected from direct rain or water, until such time as the sealant builds up a thick skin to avoid washout. Therefore, do not apply sealant when rain exposure is likely before a thick skin has develop. This is typically 24 hours in summer (25 °C or higher), but will be significantly longer in cooler, high humidity conditions.

Resources

Gyprock makes available resources that provide comprehensive selection, design, installation and maintenance guidance.