Knowde Enhanced TDS
Identification & Functionality
- Composite Materials Functions
- Technologies
- Product Families
Features & Benefits
- Materials Features
- Product Highlights
- Resistant to water and osmotic blistering
- Chemical resistance for a durable, long lasting finish
Applications & Uses
- Markets
- Application Method
- Recommended Applications
POLYCOR® 943 gel coats must be mixed prior to use. This includes prior to production spray application and when obtaining material for patching or any material that has been set aside for patching. Several suitable types of mixing equipment and styles of agitators are available for both pails and drums. Regardless of the specific type used, the equipment must have sufficient horsepower (relative to container size) to achieve thorough circulation from top to bottom and out to the sides of the container. The agitator must be properly sized for the container and must allow for uniform mixing regardless of the liquid level in the container.
Mixing once a day for 10 minutes is typically sufficient. Do not overmix POLYCOR® 943 gel coats. Overmixing can break down the polymer coating viscosity increasing the tendency to sag. Overmixing can also result in styrene loss which could contribute to porosity. Air bubbling should not be used for mixing. It is not effective and only serves as a potential source of water or oil contamination. POLYCOR® 943 Series gel coats are generally formulated spray applications. Brushing or rolling is not recommended. Refer to Polynt’s Composites Applications Guide for equipment and application recommendations.
Polynt does not recommend fluid lines longer than 50 feet, or pumps smaller than 20:1 ratio. Polynt 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. Ask about and adhere to all equipment manufacturers’ recommendations.
When establishing the fan pattern for the spray equipment, use the lowest pump pressure needed to achieve a good fan pattern (no fingers or tails, uniform particle size of about 1/16²). Use of higher pressures can lead to porosity or excessive overspray. Overspray can result in a leathery or chicken skin texture if it falls on the part surface. To minimize overspray that falls onto the mold, plan the spray pattern so that the beginning is closest to the vapor/air exhaust and progresses to the opposite mold end. The spray pattern should also allow for a wet line to be maintained.
A spray distance of 18 to 36 inches is recommended. Closer spray distances can result in blowing of the film or air entrapment. Spraying at distances greater than 4 feet will increase orange peel and porosity. For deep channels, recessed, and hard-to-spray areas, an extension nozzle is highly recommended.
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. If water blisters are of great concern (boat hulls), 20 to 24 mils would perform better than a thinner film, but resistance to sag, porosity and cracking could suffer. If weathering (yellowing from sunlight, decks) is of great concern, then thinner films (12 to 16 mils) would perform better, but patchability, print-through and blister resistance could suffer.
Proper mold maintenance is important. Although POLYCOR® 943 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 | — |
| Viscosity Brookfield RVF #4 Spindle at 4 rpm at 77°F (Colored) | 16,000-19,500 | cps | — |
| Viscosity Brookfield RVF #4 Spindle at 4 rpm at 77°F (white and off white) | 9,000-14,000 | cps | — |
| Thixotropic Index at 77°F | 6 | — | — |
| Flash Point at 77°F | 82-88 | °F | — |
| Volatile Organic Compounds at 77°F | 35-50 | % | — |
| Weight per Gallon at 77°F (depending on color) | 9.0-11.0 | — | — |
| Gel Time at 77°F | 10-17 | minutes | — |
| Lay-up Time at 77°F | 45-80 | minutes | — |
| Hide (most formulations) at 77°F (Completed) | 10 | mils | — |
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 and Norox® MEKP-9H, Akzo Nobel CADOX® L-50a 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 3.0% 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 80 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 45 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 POLYCOR® 943 Series 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) have a shelf life of 60 days. The 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.