A Vermont Castings Resolute Acclaim, with about 1 cu. ft. firebox, and a 6" flue. I had to do a major cleanout of the chimney liner and flue pipes last month:
http://handymanwire.com/ubbthreads/ubbth..._Cap#Post701801
I attributed that to not burning hot enough due to our mild winter, and subsequently left the air control on high. Well, late last week we began to notice smoke escaping from around the gaskets and pipe connections. I let it burn out, and went up on the roof with brush and rods, expecting to find a gooey creosote clog like before. Surprisingly, the brush went all the way down to within 3' of the "T". I went inside, took the cleanout cap off, and snaked upward with a length of BX. I broke up a big clog of solid creosote not more than 4' from the stove!
I couldn't understand why that should happen until I did a close inspection of the stove and found a 1/4" gap at the bottom of the pipe going into the stove flue collar! I suspect this was allowing room air to be sucked in, bypassing the stove, and cooling the flue gasses. I jammed the pipe into the flue collar, placed a few screws, and taped the joint with aluminum tape. We'll see how that works.
Question: Does anyone have a rule-of-thumb about size of logs in a stove. A 6" log has the same amount of wood whether whole or quartered, but the split pieces have more than 2X the surface area, and will burn faster (and hotter). I think a mistake I've been making is trying to burn logs that are too large for the stove. What say you all?

It takes longer for an intact log to season than if it is split - maybe that is your problem. If you listen carefully and hear any hissing in the fire, that means there is moisture being evaporated.

let's see. we heat with wood. put in new stove 2 years back and get at most a half cup of yuck from chimney and inside pipe per year. so you are doing SOMETHING wrong. check all of the connections. don't put one big six inch log in and let it burn. in fact don't put in anything if you can't fit THREE of them in in a triangle. heat it up decently hot once every time you use it. will save you a lot of trouble.

oh well, I am off to the backwoods to cut some firewood for NEXT year. ront

The wood is seasoned 2-3 years and not giving off steam. Ront's suggestion of not adding wood that I can't fit 3 at a time is on the mark. It's going to be more wear & tear on my maul and shoulders, though!

You mentioned tapeing, with aluminium tape, the flue-pipe/flue-collar connection. I may be way off base here, but it seems to me that while the aluminum is quite heat proof, the gum on the backside may be less so. I'd suggest sealing it with silicone or even furnace cement. Silicone would be pretty easy.

but it would last only if you use the high temp stuff. other than that, based on where he is putting it, it will just melt. ront

I seal my chimney connection to the stove collar with furnace cement - no problem. Looking at your earlier post pictures you're getting creosote buildup because your piping is not insulated - it's cooling down almost instantaneously; that 1/4" gap you found probably made little difference to the build up. Monitor the temperature of your fire rather than be concerned with the size of your logs. If you have a good bed of embers you should be able to put a tree trunk into the stove without a problem, if you adjust the draft to keep it hot enough.

issue is a single log burning will never generate enough heat and draft to keep it hot enough. multiple smaller logs will help greatly. and don't 'damp the fire down' when you go to bed or it will produce creosote all night as stack temps drop below like 275 degrees or thereabout. ront

So far so good. I've been able to maintain the temp between 300-450 degrees by adding smaller pieces of wood more frequently, and adjusting the air intake. I can bring it to 500 degrees by moving the intake to the start-up position, which I've been doing for 1/2 hour in the morning. I haven't even had to scrape the glass door!
I've also been leaving the ash bed fall through the grate naturally, instead of stirring it up with a shovel. It seems to make the embers last longer (and hotter).

Grate!

(pun intended)

In my fireplace I prefer to let the ashes pile up under the grate, or in the stove I don't use a grate. Helps reduce the uncontrolled draft under the flame, promoting longer burn times.