- Thermoplastic should not be heated more than 3 times.
- Thermoplastic should not be heated to 190 - 200 degrees Celsius for more than 4 hours.
- Colour change is clear indication that the material has been overheated.
- Thermoplastic should never exceed 230 degrees Celsius.
- Pre heater stirrers should be set between 30 - 60 RPM – excessive stirring will cause aeration on the surface similar to a milkshake.
- If material remains in preheaters and machine, stirrers should remain on until material cools to 150c and material should be drained from extrusion arm to avoid settlement.
- It is advisable to sieve preheated material upon transfer to reduce blockages.
Correct Application of Thermoplastic:
- Extrusion thermoplastic must be applied between 185 - 200 degrees Celsius to ensure adequate bonding to the substrate.
- Surface applied beads should be achieving an approximate embedment of around 60%, with quantity and type specified by state / contract.
- Test plates should be used regularly, checking that conforming thickness of 2 - 3mm is achieved.
- Material should be ‘blown out’ into a tray prior to a run, until material is flowing correctly without tears and at correct application temperature.
- Ensure crews are regular checking material temperature.
Application temperature is the primary cause of bond failure and operators should be checking both machine gauges and testing material temperature when blowing initial material into trays and on point of application.
To avoid the risk of delamination, thermoplastic should be applied at temperatures above 10 degrees Celsius.
- Surface must be above 10 degrees Celsius and should be checked with infrared thermometer prior to linemarking.
- Primer must be applied when extruding onto aged asphalt where aggregate is exposed or oxidized and MUST be applied to all concrete surfaces. This can be obotained in 20L drums from Crystalite.
- Surface must be free of all dirt and debris. Remove any residual poorly adhered markings and curing compounds.
- Heavy build up of existing pavement markings and temporary traffic tapes will require removal.
- For the above two points, surface may be cleaned with air blower, brooming, grinding or waterblasting, depending on situation.
- Surfaces must be completely free from moisture as thermoplastic will not bond when moisture is present. For concrete, water must not have been present for at least 3 days prior to marking.
- Circulating oil is critical to a machines performance and should be scheduled to change per manufacturers recommendation.
- Poor circulating oil can result in loss of heat and can lead to adhesion issues. Head temperature can be observed by an infrared thermometer and should be monitored when checking material temperature prior to starting run.
- Machines thermometers should also be calibrated regularly and checked by infrared thermometer.
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RYAN WALKER CAN BE CONTACTED ON 0407 766 796