How to Cure Sealant

Sealants may come in a cartridge and be dispensed with a caulk gun.

Sealants come in two basic chemical formulas---condensation cure, which uses moisture to activate the curing, and heat cure, which requires heat to activate. Moisture cures typically come in a one-part system, in a tube or cartridge, and are applied with a gun or applicator. Heat cures may be one or two part. Two-part cures often come in buckets and require mixing and application with special tools.

Difficulty:

Easy

Instructions

Things You'll Need

• Sealant
• Hair dryer or other source of heat
• Spray bottle with water
• Methanol (optional)
• Accelerator/curing compound (optional)

1. Choose a sealant based on the nature of your job. Read product instructions and label thoroughly; note that one-part sealants, which usually come in a cartridge and are typically applied with a gun, require no further mixing before application. Two-part sealants, on the other hand, must be mixed.

2. Mix two-part sealants with a chemical accelerator according to instructions. Purchase an accelerator that comes with the sealant or a compatible product, if possible.

3. Apply sealant as directed, using a caulk gun, spatula or similar tool. Spread as thinly as possible (while using an adequate amount) for the quickest cure and less costly waste. For best results, apply at warm temperatures with a warm product, regardless of formulation.

4. Cure the sealant more quickly by exposing applied sealant to either higher heat or humidity, depending on formulation, which will be noted on the product. Use a blow dryer or other heat source to heat sealants that cure with higher temperatures; spray sealant with water or a mixture of water and up to 50 percent methanol in freezing temperatures to cure sealants that react to moisture.

Tips & Warnings

• High moisture is defined as over 75 percent. Use of a humidifier or any other moisture source will speed curing of moist cure sealants.

• Read product instructions carefully. Some sealants should not be exposed to heat sources other than room temperatures. In these instances, you can use an accelerator or allow it to cure at the normal rate.

References

• ACC Silicones: Silicone Adhesive RTV & Heat Cure
• China Sealant: FAQ
• APT Sealant: Thread Sealant: Basic Usage Guidelines
• Choksey Chemicals: Sealant Product Specs: Mixing (Uses Accelerator)

Resources

• Pecora: Challenges in Sealant Application (PDF)