Burning wood as a primary heat source for almost 40 years has given me an interesting understanding of wood burning stoves and how they best function. I change the door gasket regularly but wanted to find out how often manufactures recommend the gasket be changed. This is what I found.
How often should the door gasket be replaced on a wood burning stove? The gasket should be changed at least one time a season to maintain the proper seal. My research turned up these facts regarding the door seal including the types, sizes, and kits that are available.
Why Replace the Gasket?
Wood burning stoves burn wood. As obvious as this is, wood is not a clean burning fuel like natural gas or liquid propane gas. The chemical reaction of burning wood creates a residue that is left behind on the walls of the stove and in the chimney. This residue known as creosote is tar like substance that causes several issues. One issue is the hardening effect it has on the door gasket.
Once the creosote is in the gasket, the gasket becomes hard. For the gasket to work correctly, it must remain soft and allow the door to squeeze the gasket when closing so it seals properly. A gasket coated with creosote should be replaced. The hardened gasket will restrict the closing of the door and allow too much air into the firebox. This affects the control of the stove temperature and reduces the efficiency of the stove.
If you do not have issues with creosote buildup on the door seal, it will eventually become worn from use. The repeated opening and closing of the door or doors will eventually wear out the fiberglass, crushing it to the point where it is in effective, also not creating an airtight seal.
Check your door gaskets for either crushing or creosote coating and replace as needed. If neither of these is noticed, replace the gasket annually to make sure you have a good seal each new burning season. You will notice the difference.
How Door Gaskets Work
Door gaskets for wood burning stoves are constructed of woven fiberglass material much like rope. The fiberglass is then coated with graphite. The fiberglass is flexible and designed for extreme temperature. The graphite is added as a lubricant to keep the fiberglass soft and flexible.
The gasket usually sets in the slot in the door or stove face. When the door closes, the rope is squeezed and airflow is restricted. The rope material is designed to be opened and closed many times before requiring replacement.
The gasket is held in place with a high temperature silicone caulk or glue. The glue will harden and hold the gasket in place until it is removed by scraping with a putty knife or screwdriver.
How to Change
Changing the gasket is a simple process with 5 steps that should take under an hour to accomplish.
- Cool the stove or doors (if gaskets are on the doors.) the stove should be cooled under 100 degrees F to work on the surface. The silicone caulk that holds the rope needs a cool surface for application and to dry properly. For my stove, I let the fire drop to less than 200 degrees F and remove the doors. They set outside for an hour and are cool enough to work on.
- Remove the old rope and scrape off the old silicon/glue. It will take scraping with a screwdriver or putty knife to get all the old glue off. Remove it all! If you are working at the stove itself, put a drop cloth in front and under the stove to catch all the chips that fly off when scraping.
- Measure the rope by holding it in place. Leave an extra inch at the tail end. That is easy to cut off once glued in place. A rope knife or sharp scissors will cut the rope. (Note do not use your wife’s good sewing scissors – bad mistake).
- Apply the silicone caulk to the channels. A small amount goes a long way. It should not be running out of the channel and on the door or face of the stove.
- Install the gasket. Place the gasket in the channel against the glue. Do not stretch the rope, allow it to lay in the channel naturally. Cut off any excess without pulling the gasket from the channel. I recommend closing the doors to press the gasket in place.
Follow the silicone manufactures recommendations on drying time before heating the stove up to temperature. Clean up!
Types of Rope
The fiberglass rope is available in a variety of sizes and shapes. Whatever your stove requires, there is a fiberglass rope kit that fits your stove.
They are available in flat, round, and tadpole shaped. Sizes from 3/8″ to 1″ round and flat.
Match the rope you have with a new rope exactly to create the seal that your stove was designed to have. Re-creating the factory seal will ensure that your stove operates at peak efficiency.
Kits
Kits can be purchased from many manufactures that will have the size/thickness and length you need. A tube of silicone caulk will generally be included in the kit.
To save returning and re-purchasing, make sure you measure the thickness of the rope and length required so you can purchase the right product the first time.
There were multiple listings from the following manufacturers: Rutland, US Stove, Englander, Lavalock, Taraglass, and Fire Black. Each has multiple sizes and shapes of rope and sells complete kits or rope in bulk.
Finding your size and shape is not difficult. Make sure you are replacing your gasket on a regular basis.
Conclusion
Maintaining your wood stove system in peak operating condition is critical. If air is leaking into the stove through the door, the system will not operate as designed. Taking just a few minutes each season to replace the door gasket is simple procedures that can make your stove more efficient, and save you time and money in the overall amount of wood burnt.
If you burn less wood in a season, get more heat out of the stove, and end up with less creosote in the chimney it is well worth the time.
With so many brands and versions of gasket material available at the click of a mouse, just take the time and have a spare kit on hand when you need it.
Additional Questions/Articles
If you enjoyed this article you may want to check out my article on “How to Paint a Wood Burning Stove.” Another article titled, “The 16 Wood Stove Must Have Accessories” may also be of interest.