Cast Iron stoves and leaky joints

[GSPdog]

I have an old Vermont Castings Defiant wood stove and wonder if other folks have had problems with cast iron stoves leaking smoke into the home. Is this a chronic problem with all cast iron stoves, or just older units? I try to burn the stove hot to minimize the creosote but I think by doing so the cast iron expands enough to crack the cemented joints. The stove temp occasionally approaches 700 degrees but I didn't think that was too much of a problem for these old proven stoves. Has anyone else had problems with leaky joints on cast iron stoves?

 

[webbie]

Cast iron and furnace cements are never airtight in the sense of the word.....that is, they always have lots of small holes and cracks in the seams. If you get smoke out, that is not because the seams are unsealed - but it's because the draft of the chimney is low.

Let me put it another way. I have seen smoke pour out right through welds, seams, gaskets - sometimes heavily, when chimneys reversed (push down instead of up, like when starting, etc.).....

Leaking joints should always be pulling in - IF the chimney draft is correct.

Look at the stove pipe and the chimney as the solution to your problem......make sure the pipe joints are cemented together, the connection to the chimney tight, the chimney tall enough, etc.

Think about it - lots of old stoves have very large open air inlets on the bottom and top door - smoke doesn't come out of them, rather air suck in. Same goes with cracks in the cement of the seams, etc.

 

[DougA]

I had one incident a few ago that I was going to post, then thought again and decided not to. I've got a early 80's VC Resolute that I also burn a bit hot, just to get enough heat this winter. I get occasional mild backpuffing, especially when weather conditions and wood are not right. Last week I was sitting nearby and everything was burning fine when I starting getting high temps, my Aubrins alarm went off at 900 so I closed the air down. I thought it was over when suddenly, the entire stove belched/shook (can't think of a better term) and I saw smoke rushing out of every joint and seam that existed. In 30 years, I've never had that happen. My Aubrins alarm was still going, my smoke detector went off and the place sounded like Friday night at McDonalds. A few moments later, the Aubrins went below the alarm threshold and I opened the window and the detector stopped. I was never worried, just trying not to choke on the smoke.
So to answer your question, YES older cast iron have plenty of joints that can leak and my guess is that it's more old age that over heating. My plan is to retire the stove as soon as the weather gets a bit warmer but if you're not ready for that, I would pull it completely apart and make sure all joints are inspected, apply new cement, new gaskets and you should be good for another decade. If you're not comfortable doing this, there are lots of people around that offer the service. The risk is that the more leakage you have, the less ability you have to control the burn. I know for sure that is the case with mine.