Is it possible is "heat" up a wood stove TOO fast???? From a cold start I mean. Enough to crack welds or crack cast iron. For a modern stove; I'd think this unlikely, but I've been around these forums enough to know better!!! Just would like to get a discussion going. What say y'all
maybe if you went from cold start to air wide open and let it go till it was smoking the paint off. generally speaking, cast iron is pretty soft and a bit brittle. you dont want to shock it. but it is a pretty tough stuff in that it will expand and contract with each heat cycle.
In my experience with many 40 degree starts in my plate steel stove using firewood and going to 700+ ASAP, no, nothing has failed from it. I don’t give a single thought to slowing down the warm up other than keeping flue temps safe and not blowing past 700 on the stove. No parts glow. My particular plate steel stove actually changes shape as it heats so the door gets looser and I need to tighten it a couple of times during the warm up.
This sage says go to it. But, if your space is say 30 F, it makes sense not to blowtorch the firebox. Treat it like you're making love.
Yes, it is possible, but not probable. However, if you happen to have a soapstone stove, then by all means don't try to heat it up too fast especially with the first fire of the fall or winter because there may be moisture in the stone and if it heats too fast it could crack the stone. That said, we generally heat our stove a bit faster than is suggested. Yet, we have a small problem with our flue. That is, it runs horizontally through the wall to the outside then a 90 degree. In effect, this horizontal pipe heats super fast, at least on the top so that we have to turn our draft down rather quickly when starting a new fire. For example, this morning I started a fire from scratch again and within 5 minutes I had to turn the draft down to 50% then another 5 minutes I checked and turned it down even more as the flue was at 500 (single wall).
I can't speak for the stove but an instant hot fire can play hob with your chimney! 2 years into our new house years ago, we had a large Schrader stove. The flue went up about 3 feet then into the wall to the chimney. We had had drenching rain for days then an extreme cold snap. Next morning I loaded the stove with lots of kindling and smaller pitchy splits and it took off like an f16 on afterburners. I'm sure flames were running all the way up the pipe and blow torching the opposite wall of the chimney. There was a sudden bang and the whole house shook as though from a blow. I went outside and there were some large cracks in the chimney just opposite where the pipe entered into it. Whether it had something to due with excess moisture frozen in the brick turning to steam or just massive thermal expansion, I don't know. Since I had built the chimney maybe it also could have had a design flaw of some sort. At any rate we had a new one built by a professional with no problems since. I am of the opinion that any sudden heavy thermal loading to your cold chimney, wood stove, diesel pickup truck or what ever, can't be a good thing!
No gasoline. As I said, pitchy splits of Fir wood. These take off like a blowtorch. The old Schraders were single walled and no baffles to speak of. None of the technology we have today. The pipe outlet was in the center of the top of the stove and all the fire went straight up the pipe and 90* into the chimney. In 5 minutes you can have an 8 inch blowtorch aimed at the back wall of your masonry chimney that is at single digit temperatures. Obviously now have a better sealed chimney, more advanced stove that heats slower and know better than to start with a load of small pitchy splits. The Moral is the same: Rapid thermal shock can be damaging to almost anything!
I’ve been working through about a cord of nothing but pitchy fir splits from the bottom of huge trees. Apparently the tree service log buyers don’t want that pitchy butt wood.
Those butts are quite fibrous and interwoven. I usually try to keep the pitchy splits fairly large, that way they burn slowly. You are right, the log buyers don't like them but they are BTU dense and make great firewood!
Yep, as a mason I’ve seen it plenty on exposed chimneys. Masonry doesn’t expand or absorb heat quickly when it’s really cold outside. You can split a chimney right up with a quick high heat condition. Usually vertical cracks. A lot of new homeowners decide to burn all their cardboard in fresh chimneys or fireplaces. Often there’s not even heat in the house yet. There’s a certain low temp, not sure what it is but when you get below that things go pop.
