Cast iron is a pretty sturdy material, so if your cast iron wood-burning stove has started to crack then something has gone wrong.
So what might be causing the body of your wood burner to crack?
There are a few factors that could cause a cast iron stove to crack. We’ll explore some of the most likely reasons:
Lack of flue support
Wood-burning stoves are not designed to be load-bearing. If it is properly designed, your flue system should incorporate its own support so that the stove body does not have to take the weight of the flue.
If the stove is supporting the flue system, this can lead to problems. The cast iron stove will expand and contract during use, much more so than the steel used on flue collars. As a result, loading onto the flue collar can lead to fractures.
Overfiring the stove
Overfiring is forcing your wood burner to operate at a higher temperature than it should by allowing too much air into the stove. This can be caused by using the wood burner when its rope seals have worn out, leaving the door open or modifying the air controls.
Too much fuel
Overfiring can also be caused by using too much fuel or using the wrong sort of fuel. Too much coal or wood can create an intense fire that is too hot.
You can ensure that the stove is not overheating by using a flue pipe thermometer to keep a check on the flue gas temperature. This will also help you to achieve a more efficient burn and save you fuel.
A worn or absent baffle
If your stove’s baffle is worn or missing entirely, the flames will create a hot spot on top of the stove where they come into contact with the flue collar.
The baffle would ordinarily encourage the flames to push evenly across the surface area of the stove, preventing the flue collar from being susceptible to additional heat.
If the damage is already done, you can look for replacement parts in out Stove Spares section.