Preparation and Application Instructions for Tremco Dymonic FC Sealant

Preparation and Application Instructions

The minimum width and depth of any sealant application should be 1/4" by 1/4". The depth of the sealant may be equal to the width of joints that are less than 1/2" wide. For joints ranging from 1/2" to 1" wide, the sealant depth should be about half of the joint's width. The maximum depth of any sealant application should be 1/2". For joints that are wider than 1", contact Tremco Technical Services at 866.209.2404.

Prep Work

Target surfaces must be unblemished, clean and dry. Any release agents, existing waterproofing, dust, loose mortar, laitance, paints, or other finishes must be removed before application begins for best performance. Tremco recommends thorough wire brushing, grinding, sandblasting, or solvent washing depending on the contamination of the substrate. Tremco also recommends that surface temperatures be 40 degress F or higher when this silicone sealant is applied. If the sealant has to be applied in temperatures below 40 degrees, please refer to the Tremco Guide for Applying Sealants in Cold Weather. Tremco Dymonic FC adheres to most common construction substrates without the need for priming, however, it is always a good practice to perform a mockup or field adhesion test before you begin your project so as not to waste your time and resources. A description of the field adhesion test can be found in Appendix X1 of ASTM C 1193, Standard Guide for Use of Joint Sealants.


Tremco Dymonic FC is easy to dispense with conventional caulking equipment. Ensure that the backer rod is friction-fitted properly and any primers that have been applied. Fill the joint completely with a proper width-to-depth ratio and tool to ensure close contact of the silicone sealant with the joint walls. Dry tooling is always the preferred finishing method although xylene can be used in limited amounts to slick the spatula, if needed, following the initial application. For a nice, clean finish, apply masking tape to the sides of the joint prior to filling the voids.

Cure Time

Dymonic FC silicone sealant will cure at an approximate rate of 3/32" per day at 75 degrees F and 50% RH (relative humidity). Dymonic FC will also skin in 1 hour and be tack-free in 3-4 hours. The cure time will increase as temperatures and/or humidity reduces. The rule of thumb is to add one additional day for every 10 degrees F decrease in temperature.

Clean up

Excess sealant around and near the joint interface should be carefully removed with xylene or mineral spirits before the sealant begins the curing process. Any application tools can also be cleaned with xylene or mineral spirits. Note: Xylene is a hazardous material and needs to be handled with caution.


  • Do not apply over damp or dirty surfaces
  • Use only when adequate ventilation is present
  • Do not use under polyurethane deck coatings unless the sealant has been given sufficient time to cure
  • Always utilize the accompanying SDS for information on Personal Protective Equipment (PPE) and health hazards.

DISCLAIMER: These instructions are from the product manufacturer. PK Supplies Inc. makes every effort to ensure that these instructions are accurate. By following these instructions you agree that PK Supplies Inc. is not liable for any damages or losses caused by these instructions.

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