Knowde Enhanced TDS
Identification & Functionality
- Composite Materials Functions
- Technologies
- Product Families
Applications & Uses
- Applications
- Application Method
- Application Method
Do not overmix POLYCOR® 947 gel coats. Overmixing breaks down gel coat viscosity, increasing tendencies to sag, and causes styrene loss, which could contribute to porosity. Gel coats should be mixed once per day for 10 minutes. The gel coat should be mixing to the sides and bottom of the container with the least amount of turbulence possible. Air bubbling should not be used for mixing. It is not effective, and serves as a potential for water or oil contamination.
SFP gel coats are generally formulated for both airless and conventional spray application. Brushing or rolling is not recommended. Refer to PB-16 (Application Guide) and PB-3 (Equipment Selection) Bulletins for additional, specific recommendations.
Polynt Composites recommends a gel coat delivery rate of no more than 2.5 pounds per minute with conventional air-atomized equipment, and no more than 4 pounds per minute with airless equipment.
For optimum results, uniform catalyst mix must be achieved. Even with the equipment properly calibrated, potential problems can occur due to: poorly atomized catalyst; surging problems (gel coat or catalyst); poor tip alignment (catalyst to gel coat mix); contamination; and poor application procedures, which will quickly negate all benefits of calibration. The equipment and application procedures must be monitored on a routine basis to ensure proper application and cure of the gel coat. Adhere to all equipment manufacturers’ recommendations.
Avoid overspray settling on mold surfaces by starting the spray pattern closest to the vapor/air exhaust and progressing to the opposite mold end. Maintain recommended spray distances from the mold surface. Closer spray distances or larger tips may be required in hot weather to avoid dry spray buildup.
For best overall performance properties, a wet film thickness of 18 ± 2 mils is recommended as ideal. Films less than 12 mils may not cure properly, may be hard to patch, have more print-through, and are more susceptible to water blisters. Films above 24 mils may pre- release, trap porosity, crack and are more subject to weathering discoloration.
Proper mold maintenance is important. Although POLYCOR® 947 gel coats have excellent patching properties, minimal repair work is always desirable. Sanding and compounding can hasten the chalking and loss of gloss of all gel coats.
Properties
- Color
- Typical Properties
| Value | Units | Test Method / Conditions | |
| Sag Resistance at 77°F (Good) | 20 | mils | — |
| Hide (most formulations) at 77°F (Completed) | 10 | mils | — |
| Lay-up Time at 77°F | 45-60 | minutes | — |
| Viscosity Brookfield RVF #4 Spindle at 4 rpm at 77°F (White and Off-Whites) | 15,500-20,500 | cps | — |
| Viscosity Brookfield RVF #4 Spindle at 4 rpm at 77°F (Various Colors) | 10,000-18,000 | cps | — |
| Thixotropic Index (2/20) at 77°F | 7 | — | — |
| Flash Point at 77°F | 85 | °F | — |
| VOC at 77°F | 39 | % | — |
| Weight per Gallon at 77°F (depending on color) | 10.0-12.5 | lbs/gallon | — |
| Gel Time att 1.8% MEKP at 77°F | 12 | minutes | — |
Technical Details & Test Data
- Cure
It is recommended that gel time be checked in the customer's plant because age, temperature, humidity and catalyst will produce varied gel times. All data referencing gel or cure refers specifically to Arkema Luperox® DDM-9 catalyst. United Initiators Norox® MEKP-9, Norox® MEKP-9H, Akzo Nobel CADOX L50a and CADOX D-50 are expected to yield similar performance. Arkema Luperox® DHD-9, United Initiators Norox® MEKP-925 and Norox® MEKP-925H, and Pergan HP-90 may yield slightly shorter gel and cure times.
The catalyst level should not exceed 3% or fall below 1.2% for proper cure. Recommended range is 1.2% to 3.0% with 1.8% at 77°F being ideal. Normally, the gel coat film is ready for lamination in 45 to 60 minutes. This time element is dependent on material temperature, room temperature, humidity, air movement, and catalyst concentration. Special fast-cure versions are available but must be requested. These products offer lay-up times of 30 minutes or less depending on gel times. Fast cure products have shorter stability and should not be inventoried over 45 days.
These products (standard or fast cure) should not be used when temperature conditions are below 60°F, as curing may be adversely affected.
Storage & Handling
- Handling and Storage
Uncatalyzed, standard cure gel coats have a shelf life of 120 days from date of manufacture when stored at 73°F or below, in a closed, factory-sealed, opaque container, and out of direct sunlight. Fast cure gel coats (gel time less than 9.0 minutes) are stable for 60 days. Shelf life is cut in half for every 20°F over 73°F. Totes of product can have even shorter shelf life – 66% of that for drums.