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Fire sealant: Strong bonds that can take the heat

Read on to learn to use fire sealant – the preferred material for doing repairs and filling gaps inside the fireplace. It’s rated for high temperatures and very durable.

What is fire sealant?

Fire sealant is a type of caulk formulated to stand up to extreme heat. It will seal gaps where smoke, flames, or extreme heat might escape and cause damage. Fire sealant is used commercially to contain smoke and fire to one area within a building, but it can also be employed at home. Use it to seal gaps or to keep firebricks in place.

Choosing the right fireplace sealant

Here are a few tips to help you choose a good fireplace sealant.

First, make sure it is truly rated for the heat that it will encounter inside the fireplace. Ratings of around 2000°F (1090°C) are appropriate. Also, consider the curing time. Most fire sealants will cure within a few hours.

If you are going to use it inside your fireplace, the fire sealant must be rated for indoor use. Most are, but it’s a good idea to check.

Finally, if the fire sealant will be visible, choose an appropriate colour. Some fire sealants are a deep red for easy identification, but that might not go well with your colour scheme! Fireplace sealants are available in various neutral colours such as grey and black.

Make sure the fireproof sealant is fully cured before using the fireplace. Starting a fire too soon could cause the sealant to fail.

Applying fireplace sealant

Most fireproof sealants come in a standard caulking tube for easy application. Follow these steps:

  1. Clean the area to be sealed and ensure it is free of dust, soot, or other contaminants.
  2. Place the fire sealant tube into the caulk gun and cut the nozzle end to the desired width.
  3. Apply the caulk evenly to the surface in question and smooth it out with a caulking tool if it will be visible once dry.
  4. If you are using the fire sealant to secure a loose firebrick, apply generously to the back of the brick and press firmly into place. Secure the brick until the sealant dries.

Clean up tools and any spills or excess sealant immediately with soapy water and a cloth. If you find some excess sealant after it has dried, you will need to remove it mechanically by scraping with a putty knife or using a razor blade.

If you need a quick fix for stone, concrete, or brick in areas not prone to extreme temperatures, try Loctite Epoxy Metal/Concrete. This is a two-part epoxy which dispenses from a dual syringe for easy mixing. Once mixed, it will harden into a tough, high strength bond in just 5 to 12 minutes. It’s strong enough to hold loose stones in place, fill most gaps in cracked concrete, or strengthen a loose metal railing. This highly versatile adhesive bonds to glass, ceramic, and wood, as well as masonry surfaces.