I had replaced a couple secondary air tubes back in 2018 while I was checking the stove and chimney all over getting ready for the heating season. I noticed in late December that one of the tubes was hanging low and had a large flame pattern blowing down like it was cracked. We had some warm days so I cleaned the stove out and looked at the tube. It was worse shape than one of the old ones that I had replaced before. Being a true hoarder, I had kept the old parts. I kinda straitened the least damaged one and put a stainless steel hose clamp around the pipe where the crack was and put the repaired tube back in. They bend fairly easy when they are up to temperature (glowing) when bumped with a 10 pound split. They tend to crack when trying to straighten them at room temp. I've been running the "repaired" tube for a month now and have been keeping an eye on it. It's starting to droop down in the way of putting a full load in so I'm gonna change it the next "warm" day we have. I had ordered a replacement and a spare this time as well. This is the number 3 tube and it's the one that gets wanged when the wife or I are loading the stove. We try to be careful but it just seems to get in the way when playing tetris getting ready for a cold night... I found a place this time where the tubes were a little less expensive than the last time I ordered them plus they had free ground shipping since I wasn't needing them immediately. Has anyone tried to use a "home made" tube in their stove? Do they have to be stainless steel or is there another material that would hold up under those conditions? Next stove (if I ever get there) will probably not have tubes to get in the way and get bumped and bent. Some of the better designs seem like they used a "better idea" and I'm sure that's why they were out of my budget range when I got this one.
Most people never replace a single tube in their stove...and they still look like new...either your stove uses junk material for the tubes, or you are really overheating the stove. May hold up better now since you are using the pipe damper? You will want to stick with stainless steel for those...I used black iron pipe for a DIY project stove one time...sagged in a week or two.
What stove do you have and what temps are you running at. It is pretty uncommon to go through a set of tubes in the life of the stove. Something doesn't seem right here.
They got hit with splits when loading the stove is what I believe has happened. I need to be more carefull when loading the stove with the large splits we use for overnight. Even when using the damper fully closed the the tubes are red hot once the secondaries are burning and the splits go "dark". Even when the flue temp is at 350*. I'm still fine tuning since using the damper and I will try loading less wood in since it is lasting a lot longer with the damper closed down.
I've hit the tubes with splits plenty of times, never bent/broke one...but I do tend to place the wood in and not actually throw it in like some do...
We don't just toss the wood in, but when adding wood while the secondaries are running, such as when we are going away for a few hours and we need to extend the burn time, the tubes would be more easily bent when they are glowing red hot. I've also noticed that once they are bent a little the hot / cold cycling bends them further. I'm thinking the floating end of the tube, once bent a little, may be binding in its holder hole on the floating side and causing it to bend a little more on each heat cycle. It's always the same tube (#3) that gets worse over time. They are very tight to get in and out. I'm sure air leakage at that point is to be kept to a minimum, but it still needs to float due to the heat cycling. I'm curious as to what the clearance for that hole / tube interface is designed to be. I'm thinking when I go over the stove this coming summer I may take that tube out and clean up the floating side hole for that tube and compare the fit to the rest of the tubes to ensure there is no binding. I know with our old woodstove, we used to pack it with as much wood as possible on a reload, it was indestructable. I'll go over it with the wife and make sure we aren't trying to over load it and be much more careful loading so we aren't bumping the tubes. I know I can be a bull in a china shop at times. Don't hit the tubes dummy...
Bent tube #3 popped out of it's hole today and I replaced it this evening. When I put it in a couple weeks ago, it was fairly straight, but it seemed like every day it got a little more bent. Pretty sure the heat cycling walked it out of the hole on the floating end. Very bent... Almost straight before it went in a couple weeks ago. This was a salvaged tube from an earlier replacement. As they bend, the backside blows out with a gaping hole in it I mostly covered up with a SS hose clamp after straightening the tube the best I could. It worked to get the new replacement ordered and shipped. I ordered a spare this time so I should never need to replace any again... I sanded the floating end of the new replacement down a little so it wasn't such a tight fit and looked up in there after I got the stove back up to temperature on the secondaries. No leakage flame by that tube end so I didn't get the fit too loose. This summer when I clean the stove out good, I'll check all the tubes for a loose fit on the floating end. Secondaries are all firing up like they should now.
If you notice in the first picture, the firebrick keepers are burning away... When the stove was new and I put it in 5 years ago, I noticed that the keepers were made from like the "live edge" scrap ends of steel coils and weren't all that nice looking then. I didn't think too much about it cuz they're just holding the firebrick in. At this point 5 years in there are a couple spots where they are corroded away so bad that the firebrick could fall over. The wood and coals keep them in though and I'm careful when raking the coals forward. A lower cost budget stove at $999 - 11% when I got it and overall it has done it's duty heating the whole house pretty well in a basement installation. It can crank out a lot of heat. I wouldn't want a stove this big in my living room (unless it was a HUGE living room). Knowing what I know today, would I buy it again? Maybe, but not likely. I'm a tinkerer anyway, so I can keep it going for many more seasons probably.
Yeah, those don't look like stainless. NOOOOO! There are better stoves out there, sometimes for less money. I can think of one in particular that starts with the # 30.
