Knowde Enhanced TDS
Identification & Functionality
- Chemical Family
- Composite Materials Functions
- Technologies
- Product Families
Applications & Uses
- Applications
- Application Method
- Recommended Applications
Tooling gel coats are applied to the part/plug to be duplicated. Care must be taken when preparing the plug with wax and parting film to permit positive release. Best results are obtained by applying two coats at 18 (±2) mils wet each, and allowing the gel coat to gel and cure between coats. See special film thickness precautions for 945-GA104. Apply each coat with a minimum of two passes; three passes are preferred. For best results, ensure that the tooling gel coat is allowed to breathefor two minutes between each pass. Do not allow over-spray and thin passes to go beyond 5 minutes without covering with a fresh pass. Do not apply more than 20 mils per coat, as this can result in crazing and cracking of the gel coat film after use. Do not apply less than 12 mils per coat, as poor cure can result in dulling of the mold in use. Thinner films will also exhibit more print-through and distortion. It is essential that no more than 40 mils (wet) total be applied with any of the tooling gel coat. See special application precautions. Polynt Composites Korea tooling gel coats are formulated for spray application. Brushing is not recommended.
Properties
- Color
- Typical Properties
| Value | Units | Test Method / Conditions | |
| Color (at 25/25°C) | Green | — | — |
| Viscosity, Brookfield RVF #4 Spindle at 4rpm (at 25/25°C) | 15,000 - 20,000 | mPa.s | — |
| Thixotropic Index (at 25/25°C) | 6.5 - 8.5 | — | — |
| Flash Point (at 25/25°C) | 31℃ | — | — |
| Volatile Organic Compound (at 25/25°C) | 46.5 - 49.5 | % | — |
| Gel Time (at 25/25°C) | 18 - 23 | minutes | — |
| Lay-up Time (at 25/25°C) | 60 - 90 | minutes | — |
| Barcol Hardness (at 25/25°C) | 35 - 45 | — | — |
| Hide Complete (at 25/25°C) | 22 - 29 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 NOROX MEKP-925 catalyst. ARKEMA Luperox DHD-9, NOROX MEKP925H, and Crompton HP-90 are expected to yield similar performance. ARKEMA Luperox DDM-N, Norac NOROX MEKP-9, NOROX MEKP-9H, Akzo Nobel CADOX L-50a and CADOX D-50 may yield slightly longer gel and cure times. As the material ages, it may encounter slightly longer gel times. The longer gel time will extend the casting Barcol time, but the eventual Barcol should achieve the numbers as listed under “Typical Properties.” Do not use more than 3.0% catalyst in the tooling gel coat, as this can cause excessive shrinkage of the gel coat and pull it away from the plug. For adequate cure, do not use less than 1.2% catalyst.Normally, tooling gel coats are ready to lay-up on (or spray with a second coat of gel coat) in 60 – 90 minutes – the time element being dependent on room temperature, air movement, humidity, catalyst type and concentration, and spray atomization. For best results, it is recommended that the temperature be above 25℃. When using conventional tooling resin, 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 (such as OPTIMOLDâ or OptiPLUSTM), follow lay-up time recommendations for the system being used. Application temperature and lay-up time recommendations will vary.
Safety & Health
- Product Safety
The primary reason for using tooling gel coats for the manufacture of fiberglass molds is to produce a blemishfree, durable, high-gloss surface. It is advantageous to exercise strict quality important, since many of the defects that result from poor application do not appear until the part has been removed from the mold. Many gel coat defects result from conditions that can easily be corrected. A few of these are listed below:
1. Do not use varnish as a sealer or finish coat when preparing a plug, as the styrene in the gel coat will soften the varnish, even when well-waxed and coated with a parting film.
2. Proper spray technique is very important to eliminate porosity in the gel coat film. Internal air-atomization spray equipment, airless, or catalyst injection spray equipment can result in porosity in the gel coat film if improperly applied. Tooling gel coats will not be as to tolerant of inaccuracies in a catalyst injection system as are production gel coat
3. Tooling gel coats appear thick in the container. After mixing the gel coat, it becomes sprayable. Do not over-mix, however. Over-mixing breaks down viscosity, increasing tendencies to sag and causes styrene loss, which could contribute to porosity. Tooling gel coat needs mixing when opened (and daily thereafter). 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. It is not effective and only serves as a potential for water or oil contamination.
4. Always keep the container covered (except, of course, when transferring material). An open container is easily contaminated and allows for more styrene evaporation.
5. Each coat must cure as a total film, rather than several thin films which might cure independently of each other. It is essential to cover over-spray and thin passes as soon as possible – within 5minutes. Thin, independently curing films can create a textured effect when the surface is sanded and buffed.
6. Never reduce tooling gel coat with a conventional paint or lacquer thinner, or acetone.
7. Disperse catalyst thoroughly in tooling gel coat. Poor distribution causes uneven cure, print-through, and premature release from plug before lay-up.
8. Do not over-catalyze, Excess catalyst plasticizes tooling gel coat.
9. Print-through (fiber pattern) and distortion are directly proportional to film thickness. Thicker films (not to exceed 40 mils wet total) resist print-through and distortion better than thinner films.
10. Atomize the tooling gel coat thoroughly when spraying. Low spray pressures will result in poor breakup, and will leave entrapped air in the gel coat. To check atomization for porosity, spray catalyzed tooling gel cot over glass to a film thickness to 18 (±2) mils. Laminate, pull, sand, stain and examine for entrapped air. This procedure should be followed gel coat is sprayed. These spray-outs should be saved along with other mold records.
11. In spray application of tooling gel coats, use slow, even strokes, triggering the spray gun at the end of each stroke to prevent excess buildup at overlaps.
12. Do not apply tooling gel coat over wet Polyvinyl Alcohol (PVA) parting film.
13. Install an oil and moisture trap on the compressed air line leading to the spray gun to remove lint, rust, oil and moisture.
14. Use the catalyzed tooling gel coat within its working life, with a proper allowance of time for cleanup of equipment.
15. Tooling gel coats may leave a certain amount of “coloring” when sanded and/or buffed. This is a function of the pigment used and is not an indication of cure.
16. Do not add anything, other than the appropriate methyl ethyl ketone peroxide, to
These products.
Storage & Handling
- Handling and Storage
Uncatalyzed tooling gel coats have a usage life of 60 days from date of manufacture when stored at 23℃ or below in a closed, factory-sealed opaque container and out of direct sunlight. The usage life is cut in half for every 15℃ over 23℃.