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Home > Product Line & Price List > Dymonic® FC

Dymonic FC

Dymonic® FC

Fast Curing, Low Modulus Silane End-Capped, Polyurethane Hybrid Sealant

A general purpose sealant for all normal bonding, bedding and sealing.


Dymonic FC is low modulus, one-component, moisture-cure, caulk-gun applied polyurethane hybrid sealant. Formulated with proprietary silane end-capped polymer technology, this provides the best performance characteristics of polyurethane and silicone sealants. Dymonic FC does not require a primer on most materials, but it adheres very well to cured epoxy-coated surfaces and fiberglass laminates.

Basic Uses

Dymonic FC is a durable, flexible, sealant that offers excellent performance in moving joints, is a good all around excellent general purpose sealant that exhibits tenacious adhesion once fully cured. Designed for use on bare wood, epoxy-treated wood, fiberglass laminates, perimeter caulking (windows, doors, panels), concrete and masonry construction joints,aluminum and vinyl siding. Dymonic FC is designed for interior and exterior use.


Do not apply over damp or contaminated surfaces. Substances that will contaminate a surface include glycols or products suspended in glycol, waxes or products with a wax base, substances that contain or contained silicones. Surfaces should be dry and clean to the base substrate. Penetrating epoxy coatings on the substrate should be fully cured before Dymonic FC is applied. A full cure of the Dymonic FC is required for use under a polyurethane deck coating. Use with adequate ventilation.


Stocked in 10 oz. (300 ml) gun cartridges.

Stocked Colors

colors are approximate

Black Buff Gray Redwood Tan White
Black Buff Gray Redwood Tan White

Applicable Standards

Dymoinc FC meets or exceeds the requirements of the following specifications:

  • ASTM C 920 Type S, Grade NS, Class 35, Use NT, M, A, and O
  • ASTM C 1248
  • U.S. Federal Specification TT-S-00230C Class A, Type II
  • CAN/CGSB 19.13-M87
  • Fire-Rated Systems: FF-D-1063, FW-D-1059, HW-D-1054, WW-D-1054

Application Recommendations

May be used in any vertical or horizontal joint, seam or crack. Joint width should be 4 times anticipated movement, but not less than ¼″ (6.4mm). Application tube can be cut to the width of the joint and applied to a depth and width of at least ¼″ by ¼″ (6mm by 6mm). Joints ranging from ½″ to 1″ (13mm to 25mm) wide, the sealant depth should be approximately one-half of the joint width. Closed cell or reticulated polyethylene backer rod or adhesive-backed polyethylene tape can be used to control the depth of the sealant bead on very deep seams.

Surface Preparation

For best adhesion, the joint interface must be sound, clean and dry. The joint surface may require a thorough wire brushing, grinding, sandblasting, or solvent washing. A primer such as S-1™ Clear Penetrating Epoxy Sealer can be used if desired. Primed surfaces should be fully cured before Dymonic FC is applied.


Dymonic FC is easy to apply with conventional caulking equipment. Fill joint completely with a proper width-to-depth ratio (see chart below) and tool. Curing happens at the rate of 3/32 inch (2.4 mm) depth per day at 75°F (24°C), 50% R.H., a skin should form within 60 minutes and be tack-free in 3–4 hours. The cure rate is lengthened at lower temperatures and less humidity. Dymonic FC can be painted after it has fully cured.

Tooling & Cleaning

Tooling is recommended immediately after application to insure firm, intimate contact with the joint or seam interface. Dry tooling is preferred, although tooling agents (such as xylene in limited amounts) can be used. Excess sealant and smears adjacent to the joint can be removed with xylene or mineral spirits before sealant cures. After sealant cures excess compound can be cut away with a blade. For a cleaner finish, mask the sides of the joint with a tape prior to filling.

Here is a chart that will help you estimate how many cartridges you will need for any application:

Sealant usage charts in U.S. and Metric measurements.

U.S. Chart Metric Chart

Below is a comparison of the Dymoinc FC to 3M 4200.

Physical Properties Dymonic FC 3M 4200
Consistency: Non-Sag, caulkable Non-Sag, caulkable
Hardness: (ASTM C 661) 25 40
Tack Free Time: 3–4 hrs. @ 75°F (24°C), 50% R.H. 1–2 hrs. @ 73°F (23°C), 50% R.H.
Service Temperature -40°F to 185°F (-40°C to 85°C) -40°F to 190°F (-40°C to 88°C)
Rate of Cure: 3/32″ (2.4 mm) per day @ 75°F (24°C), 50% R.H. 3/16″ (4 mm) per day @ 73°F (22.7°C), 50% R.H.
Stain & Color Change: None -
Adhesion-in-Peel: 18–25 pli -
Movement Capability: ±35% (ASTM C719) Elongation at break > 600%
Tensile Strength 300 psi (ASTM D412)

For additional information, refer to the Dymonic FC Safety Data Sheet.

PDF Documents

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Safety Data Sheets:
Redwood Tan

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