Knowde Enhanced TDS
Identification & Functionality
- Chemical Family
- Composite Materials Functions
- Technologies
- Product Families
Features & Benefits
- Materials Features
- Product Highlights
- Provide abrasion resistance
- Excellent gloss retention
- High heat distortion temperature (HDT)
- Extended mold life
Applications & Uses
- Applications
- Application Method
- Recommended Applications
The primary reason for using tooling gel coats for the manufacturing of fiberglass molds is to produce a blemish-free, durable, high gloss surface. It is to the user’s advantage to exercise strict quality control and application procedures when using tooling gel coats. Proper application is very important, since many of the defects that result from poor application do not appear until the mold has been removed from the plug.
POLYCOR® 965 Series vinyl ester tooling gel coats are formulated for air atomized and airless air-assist spray application. Air atomized (pot gun) application is recommended for best results. Brushing and rolling are not recommended. Application procedures are given below. Refer to Polynt’s Composites Applications Guide for additional information on all phases of mold fabrication.
POLYCOR® 965 Series vinyl ester tooling gel coats should be mixed prior to use. Use mixing equipment with 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. Air bubbling should not be used for mixing. It is not effective and only serves as a potential source of water or oil contamination. Do not overmix POLYCOR® 965 Series vinyl ester tooling gel coats. Overmixing can break down the viscosity, increasing the tendency to sag.
For best cosmetics and durability, Polynt recommends that molds be fabricated using 18 ± 2 mils wet of tooling gel coat followed by 22 ± 2 mils wet of Polynt’s ArmorGuard® 967 vinyl ester barrier coat. Allow the tooling gel coat to gel and cure prior to application of the ArmorGuard®. ArmorGuard® 967 improves cosmetics by reducing fiber print and distortion. ArmorGuard® 967 also provides excellent heat resistance and toughness.
If extensive sanding is expected, an alternative method is to apply two coats of tooling gel coat. The first coat should be 18 ± 2 mils wet. The second coat should be 20 ± 2 mils wet. Allow the gel coat to gel and cure between coats. This provides a thicker a gel coat layer for reworking the mold surface. Do not use barrier coat if applying two coats of tooling gel coat.
Apply each coat using three passes, with each pass having a thickness of 5-8 mils. More rapid film build could result in sag and porosity. For best results, ensure that the tooling gel coat is allowed to breathefor two minutes between each pass. Do not allow overspray and thin passes to go beyond 5 minutes without covering with a fresh pass. Thin, independently curing films can create a textured effect when the surface is sanded and buffed.
Coats less than 12 mils total wet thickness may not cure properly, may be hard to patch, and have more print-through. Coats above 24 mils may pre-release, trap porosity, and be more subject to cracking.
Polynt recommends that you include the fabrication of a quality control panel as part of your quality control program. Fabrication and testing of this panel prior to actual mold fabrication allows you to verify the suitability of the product and your process. Fabricate the quality control panel by spraying catalyzed tooling gel coat over a test mold to a film thickness to 18 ± 2 mils. Use the same equipment and settings that will be used for actual mold fabrication. Laminate behind the tooling gel. Once the laminate has cured, de-mold the panel. Sand and stain the gel coat and examine it for entrapped air. These spray-outs should be saved along with other mold records
Properties
- Typical Properties
| Value | Units | Test Method / Conditions | |
| Flash Point at 77°F | 88 | °F | — |
| Color at 77°F | Neutral | — | — |
| Weight per Gallon at 77°F | 9.07 | lbs | — |
| Viscosity Brookfield RVT #5 Spindle at 20 rpm at 77°F | 62500 | cps | — |
| Thixotropic Index (10/100) at 77°F | 6 | — | — |
| Gel Time 100 g mass at 77°F | 16 | — | — |
| Lay-up Time at 77°F | 60-90 | — | — |
| Sag Resistance at 77°F | 20 | mils | — |
| Barcol Hardness at 77°F | 30 | — | — |
| Heat Distortion Temperature One Week at Room Temperature (150°F, 16 hours) at 77°F | 144 | °F | — |
| Heat Distortion Temperature One Week after Post Cure (150°F, 16 hours) at 77°F | 189 | °F | — |
Technical Details & Test Data
- Cure
The cure rate of POLYCOR® 965 Series vinyl ester tooling gel coats depends on a number of factors including the product's age, temperature, catalyst type, catalyst level and ambient humidity. For these reasons, we recommend that you check the cure rate in your plant. POLYCOR® 965 Series vinyl ester tooling gel coats are quality control tested using United Initiators Norox® MEKP-925. Arkema Luperox® DHD-9, United Initiators Norox® MEKP-925H, and Pergan Hi-Point® 90 are expected to yield similar performance. Arkema Luperox® DDM-9, United Initiators Norox® MEKP-9, United Initiators Norox® MEKP-9H, Akzo Nobel CADOX® L-50a and CADOX® D-50 may yield slightly shorter gel and cure times.
The catalyst level should not exceed 2.4% or fall below 1.2% for proper cure. A catalyst level of 1.8% at 77°F is considered ideal. Excess catalyst can cause excessive shrinkage of the gel coat and pull it away from the plug. For best results, it is recommended that the temperature be above 75°F. As the material ages, gel times may get longer. The longer gel time will extend the casting Barcol time, but the eventual Barcol should achieve the numbers as listed under “Typical Properties.” POLYCOR® 965 Series vinyl ester tooling gel coats are ready to lay-up on (or spray with a second coat of gel coat) in 60-90 minutes. This time element is dependent on room temperature, air movement, humidity, catalyst type and concentration, and spray atomization. When using POLYCOR® 965 Series vinyl ester tooling gel coats, the gel coat should not be left overnight before being laminated onto, as the gel coat may pre-release and/or lose its tack and not provide a good bond between the gel coat and laminate. If using a low shrink/filled laminate system, follow the lay-up time recommendations for the system being used. Application temperature and lay-up time recommendations will vary.
Storage & Handling
- Handling and Storage
Uncatalyzed, POLYCOR® 965 Series vinyl ester tooling gel coats have a shelf life of 90 days from date of manufacture when stored at 73°F or below in a closed, factory-sealed, opaque container and out of direct sunlight. The shelf life is cut in half for every 20°F over 73°F.