DIY heat, and some other stuff
Over at Joels place (TUAK for you’s that don’t frequent his blog) there was some discussion about wood heating stoves and the lovable cast iron vogelzangs and others of that ilk.
I mentioned in comments that I was running and experiment on my personal sheetmetal monstrosity of thermal reactive danger, and that experiment was to determine if adding a second shell to the exposed flue pipe would help cut down on creosote build up.
I am happy to say, that is a very solid affirmative. The way I can tell, I was not able to cover the entire pipe from roof to cap and the area nearest the roof that was exposed had a much larger deposit of creosote than that area that was covered by that shell. I went ahead and cleaned out the flue again, found another piece of discard to cover the pipe from roof to cap this round and will run another week of wood through the system to see what happens.
One reason I get any build up at all is due to my flue damper (IMO) I get a good bed of coals built up then load the stove to the gills, and shut the dampers back to as closed as I can get them. This is not an airtight stove so there is always some flow through the beast. The flue damper is 1/2″ smaller in diameter than the inside of the pipe it sits in so it does not shut off flow, it merely gives it a good slow down. That slowdown also allows more heat to escape into the room and not so much out the top. It also allows the gasses to cool enough to deposit all kinds of vaporized gook (called creosote but gook works well too) all over the inside of the flue. the cooler temps outside where the flue was exposed only encourage that ‘distillation’. Sometimes, if the temps are just right, you will see that creosote flowing down sections of the pipe where it can manage to leak through. It looks a whole lot like the water that accumulated in the tarps on our vehicles while I was in Kuwait in ’92. Blech!! Smells about as healthy as well.
I digress. The fact is, if’n ya want a cheapy stove, and you want to cut down on some of the maintenance of upkeep (you will never get rid of that, only reduce it some.) definitely run a double walled flue where it exits the building/structure and continue that double wall to the cap area. The other side of it, if ya can, run your fires hot so that the flue will get hot enough to burn off any creosote that might accumulate during the initial warmup period when you start your fire. It is going to form, the only thing you can do is try to keep it to a minimum.
More laters, AFTER the holidays. Y’all have a good one. (Note to family members reading this. Don’t know what to get me, look at the wish list!!! It’s in the side bar just so you can find it! LOL)