description
Dapco 18-4F is a two-component, solvent-free, thixotropic silicone paste. Dapco 18-4F is most commonly used as a coating, sealant, or filleting material in the construction, repair and maintenance of all types of aircraft. The product can be applied using a variety of methods and is especially useful where fire resistance, exposure to phosphate ester fluids, and/or exposure to extreme temperatures -65°F (-54°C) to 400°F (204°C) are major considerations.
features
- Environmentally friendly formulation, free of heavy metals and solvents
- Good adhesion to a variety of substrates when used with Dapco™ 1-100 Primer
- Excellent fire resistance, 2000°F (1093°C) catastrophic protection for 15 minutes
- Excellent weatherability
- Performance at low operating temperatures
- Good resistance to chemicals commonly used in aerospace applications
- Qualified to Boeing BMS 5-63 & Pratt & Whitney PWA36751 specifications
- Repairable with Dapco™ 2100 Primerless Firewall Sealants
applications
- Applying: The substrate must be free from contamination, i.e. dirt, oil grease, etc. Clean the surface by wiping with a suitable solvent/cleaning agent and dry thoroughly. Apply Dapco 1-100 primer and allow to dry for 30 to 90 minutes, then apply Dapco 18-4F Sealant (Note: Dapco™ 18-4F must be applied within 90 minutes after the primer has dried). When circumstances prevent immediate application of Dapco™ 18-4F, the surface must be cleaned thoroughly to remove the primer before repeating the entire process. Handling strength is achieved in 24 hours at 75°F (24°C) (loads on the product should be limited until full cure is achieved).
- Curing: Dapco 18-4F is generally cured at ambient temperatures above 55°F (13°C). Cure can be accelerated by warming to
- 150°F (66°C) for a minimum of 4 hours. Moisture helps develop final properties (a relative humidity ranging between 30% -70% is preferred). Optimum physical properties are developed when the product is cured a minimum of seven days for sealing applications and 14 days for faying surface applications at 75°F (24°C) and 50% R.H.
- Cure may be inhibited by proximity or contact with a variety of materials including old RTV silicone sealant of the tin-cure
- variety, polysulfide, sulfur, amine and amide compounds, natural, nitrile or other organic rubbers, paper masking tape,
- plasticizers, lubricants, release agents or solvents.
- Cleanup: Before the material has cured, the excess may be removed using commercial solvent. For optimum removal of silicone residue prior to paint or coating application, Dapco 2000 diluent is recommended.
specifications
- Boeing BMS 5-63
- Pratt & Whitney PWA36751
availability
Kit sizes: ½ pint, pints, quarts, gallons 55 gallon drums
properties
| Color | Part A - Dark Green Part B - Blue Mixed - Dark Green |
| Solids, % | Part A - 100 Part B - 100 Mixed - 100 |
| Consistency | Part A - Thixotropic Paste Part B - Viscous Liquid Mixed - Thixotropic Paste |
| Density, lb/gal (kg/L) | Part A - 12.5 (1.50) Part B - 9.0 (1.08) Mixed - 12.2 (1.47) |
| Cured Specific Gravity | 1.47 |
| Shore Hardness ASTM D 2240 | Shore A: 50 |
