A Modest Success - another smoke dragon story...

[Peter B.]

The other day, it was warm enough here to let the fire burn out and do a little stove maintenance.

Since I'd already roughed out an idea for it, I also took the opportunity to install an improved supplemental air supply in my old cylindrical parlor stove. (Despite the risk of a semantics war, I'm going to refer to the supplemental air as 'secondary'.)

As described in other threads, I've modified the stove in other ways previously, but the most relevant point to remember is that there is an internal baffle in the stove which opens about 8" from the firebox floor... and through which most/all exhaust from the stove must pass before entering the actual flue and passing out of the stove. Among other things, this means coals can be mounded up near the baffle entry, and everything leaving the firebox must first pass in close proximity to the coals... which are at a temperature near (or well over) 1100*... sufficient for secondary combustion to occur.

The new supplemental supply tube feeds air through a number of drilled 3/16" holes from about 9" to 16" above the firebox floor (and very close to the baffle entry) to take advantage of the heat near the coals... a quite different 'delivery point' for the secondary air than most EPA stoves.

The results are (of course) more noticeable with a hot fire and a good coal bed. When other manual stove drafts are closed, the fire continues to burn on the secondary air alone. And internal flue and stovetop temps either stabilize or climb somewhat when the other contols are closed... when before (with a smaller diameter supply tube) they would generally stabilize or fall.

So far, I haven't made any effort to regulate the secondary flow... and today being cold and windy, the stove is running pretty hot (even clamped down fairly tight). I may end up having to screen the external orifice that feeds the tube... to limit flow somewhat.

Both yesterday and today have seen multiple burns with what gives every indication of being sustained secondary combustion... an hour and a half to two hours of elevated temps and audible flame ignition (remember, I can't see the fire) after reload - with all other stove drafts closed, and my flue damper about half open.

To drive home the point, I'm all but convinced that the cheap 1" thick catalyst in the top of the stove no longer has much effect but that of draft reduction... no temperature boost is seen on engagement anymore... yet the stovetop internal temps during a secondary burn are still running 800-1000* and the flue (at 12" above stovetop) 500-600*.

Now to replace the catalyst...

(And it occurs to me that it might be worth my while to ask for help fabricating a glass door for this thing.)

Peter B.

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[pyro68]

Speaking of fabricating glass doors, I will never forget my customer that needed replacement glass for his woodstove, did not know make or model, had the stove longer than 10 years, but the glass had cracked and he needed a new piece. The glass was not a "bay front" style, but was curved out on all four sides in soft 90* angles. I had never seen anything like it and going by the price of reg. flat stove glass, I didn't even want to think about the cost of this one. It also had little "flanges" at the side eges that the clamps on the door fit over to hold the glass in place. No one in our shop had ever seen anything, nor did we have a clue where to go for something like this. The glass beveled out approx. 2" and was flat in the front. I just happened to set the glass down on the counter upside down when I had the distinct feeling I was missing something, when I looked at the glass again, sitting flat side down, I realized I was looking at a 9" pyrex baking dish! After some laughter the customer left headed for the stores downtown!

 

[Peter B.]

Speaking of fabricating glass doors, I will never forget my customer that needed replacement glass for his woodstove, did not know make or model, had the stove longer than 10 years, but the glass had cracked and he needed a new piece. The glass was not a "bay front" style, but was curved out on all four sides in soft 90* angles. I had never seen anything like it and going by the price of reg. flat stove glass, I didn't even want to think about the cost of this one. It also had little "flanges" at the side eges that the clamps on the door fit over to hold the glass in place. No one in our shop had ever seen anything, nor did we have a clue where to go for something like this. The glass beveled out approx. 2" and was flat in the front. I just happened to set the glass down on the counter upside down when I had the distinct feeling I was missing something, when I looked at the glass again, sitting flat side down, I realized I was looking at a 9" pyrex baking dish! After some laughter the customer left headed for the stores downtown!

I assume something on the stove door concealed the brand name/trademark that's usually centered on the bottom of the dish?

When I first installed a catalyst, I found a pyrex pie dish that would fit in the recess for the round cook plate on my stovetop... and I could watch the catalyst glow briefly immediately below... but I always removed the dish before I had reason to regret the practice. (DON'T TRY THIS AT HOME )

Peter B.

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[BrotherBart]

Speaking of fabricating glass doors, I will never forget my customer that needed replacement glass for his woodstove, did not know make or model, had the stove longer than 10 years, but the glass had cracked and he needed a new piece. The glass was not a "bay front" style, but was curved out on all four sides in soft 90* angles. I had never seen anything like it and going by the price of reg. flat stove glass, I didn't even want to think about the cost of this one. It also had little "flanges" at the side eges that the clamps on the door fit over to hold the glass in place. No one in our shop had ever seen anything, nor did we have a clue where to go for something like this. The glass beveled out approx. 2" and was flat in the front. I just happened to set the glass down on the counter upside down when I had the distinct feeling I was missing something, when I looked at the glass again, sitting flat side down, I realized I was looking at a 9" pyrex baking dish! After some laughter the customer left headed for the stores downtown!

Your customer had a Elm woodstove. A Pyrex dish is exactly what is used for the glass.

(broken link removed to http://www.vermontironstove.com/about.html)

(broken link removed to http://www.vermontironstove.com/parts/pie_plate.html)

 

[Jags]

The ultimate in reducing costs by using off the shelf parts. :lol:

 

[pen]

Sounds great, add pics

pen

 

[Peter B.]

Sounds great, add pics

Of what, the meltdown...?

I just loaded 3 nice oak splits and all of the 1/4 paper grocery bag (remember those?) of creosote from Saturday's chimney cleaning.

Should be warm for the next couple of hours.

Peter B.

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[pen]

Of the secondary air modification of course.

 

[Peter B.]

Of the secondary air modification of course.

pen:

It's not in the least glamorous, but I'll try to get a shot of it tomorrow when the stove has cooled.

Got a cold snap rolling through and it's forecast to get to the subzeros tonight.

I loaded the stove at 8:30... and let her rip (closed tight except for the secondary) til about 9:30.

Had to put a restrictor in the secondary feed orifice to keep room temps in the comfort range... more than a little warm just now with the thermometer @ 75* and me sitting only 4 feet from the stove.

All the same, the flue internal temp hasn't gone offscale, and I haven't had cause for concern otherwise.

Fun stuff...

--

Still getting dark cherry on your stovetop occasionally? Post an update on your own effort when you get a chance.

For myself, I admit to being impressed... I changed nothing else but the secondary tube diameter and 'delivery' method... but I'm convinced that... well, shucks... thermonuclear is probably understatement to describe a hot reload fire.

But I 'spect it likely my total burn times may have been shortened... maybe by a good margin... and I'll be trying to gauge that next.

--

Tune in again tomorrow.

Peter B.

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[Peter B.]

In all its unadorned glory... the recently installed secondary tube.

To the right, the baffle entry... after 20 years use... (was once a horizontal cut).

At bottom, coals remaining after an 8 hour burn... enough to light off full size splits this morning...

Now pulling 550* flue internal after half an hour's 'notice'.

The old girl seems happy.

Peter B.

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[karri0n]

Peter,

I remember your other thread where we discussed at length your options for improving your secondary chamber. Glad to see you've come up with something, and that it works.


Always good to see people doing things for themselves, and not letting the corporate machine tell you that you MUST pay $2000+ for a length of pipe with a few pinholes in it to increase your stove's efficiency.

 

[Peter B.]

Peter,

I remember your other thread where we discussed at length your options for improving your secondary chamber. Glad to see you've come up with something, and that it works.


Always good to see people doing things for themselves, and not letting the corporate machine tell you that you MUST pay $2000+ for a length of pipe with a few pinholes in it to increase your stove's efficiency.

karri0n:

I'm both surprised and pleased by the result of this latest go-round. The (apparent) improvement in secondary combustion was hoped for... but not actually expected.

I admit I've been tempted recently by the $2000. 'solution'... but I'd be much less likely to alter an EPA stove... and there would go half my winter's entertainment.

Did you get your pipe damper installed? What result?

Peter B.

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[karri0n]

Got the damper, but projects pile up quickly around my house. Tonight I'm getting another woodpile shipped in, putting in the damper, fixing the upstairs shower, fixing the downstairs plumbing leading to the upstairs shower... I will hopefully have some results tonight if I don't pass out before getting to the damper.


as to your results:

I noticed you said you had hot coals left after an 8 hour burn. Did you actually gain burn time? If so, that's real nice, albeit counterintuitive.

 

[Peter B.]

I noticed you said you had hot coals left after an 8 hour burn. Did you actually gain burn time? If so, that's real nice, albeit counterintuitive.

karri0n:

I doubt very much I've added to the total burn time with the new secondary... and yes, it would be counterintuitive.

I <believe> I may have extended the usable heat production time... given that I seem to be getting a bit more of a punch during outgassing and secondary burn. But even so, it's still a leaky stove, and I don't typically get close to the times quoted by others here. (I need to do some door resealing off season.)

With the new (to me) practice of mounding the coals at the baffle entry on reload, the coals now have a tendency to 'bank themselves' overnight... often leaving a few buried embers... enough to save a match... sometimes enough to light off a new fire without kindling.

I'm also more likely now to completely close the two stove draft controls (ash pit and front door), so that there's not as often a draft directed through or over the coals... which may help extend their life.

--

In the end, I'm feeling more than a little bit stupid about my past burning habits... as well as the long lapse in my attention span with respect to stove maintenance, repair and 'refinement'. The new secondary supply is likely barely adequate, but it's a major improvement over what I had before. The new reload technique appears to aid combustion and coal longevity. Door seals - even with other seam leaks not as easy to address - are still pretty important.

All in all, I've probably wasted a good many cords of wood owing mainly to 'neglect of duty'.

Oh, well.

Peter B.

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[waynek]

I noticed you said you had hot coals left after an 8 hour burn. Did you actually gain burn time? If so, that's real nice, albeit counterintuitive.

karri0n:

I doubt very much I've added to the total burn time with the new secondary... and yes, it would be counterintuitive.

I <believe> I may have extended the usable heat production time... given that I seem to be getting a bit more of a punch during outgassing and secondary burn. But even so, it's still a leaky stove, and I don't typically get close to the times quoted by others here. (I need to do some door resealing off season.)

With the new (to me) practice of mounding the coals at the baffle entry on reload, the coals now have a tendency to 'bank themselves' overnight... often leaving a few buried embers... enough to save a match... sometimes enough to light off a new fire without kindling.

I'm also more likely now to completely close the two stove draft controls (ash pit and front door), so that there's not as often a draft directed through or over the coals... which may help extend their life.

--

In the end, I'm feeling more than a little bit stupid about my past burning habits... as well as the long lapse in my attention span with respect to stove maintenance, repair and 'refinement'. The new secondary supply is likely barely adequate, but it's a major improvement over what I had before. The new reload technique appears to aid combustion and coal longevity. Door seals - even with other seam leaks not as easy to address - are still pretty important.

All in all, I've probably wasted a good many cords of wood owing mainly to 'neglect of duty'.

Oh, well.

Peter B.

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In assuming you are talking about re-sealing the feed doors and would appreciate your thoughts on that.

Jackpine

 

[Peter B.]

In assuming you are talking about re-sealing the feed doors and would appreciate your thoughts on that.

jackpine:

Both my loading doors and the ash pit door leak a bit at present. In past, I've found it frustrating that the stove castings are not (quite) good enough to make a perfect seal alone, but 'too good' to accomodate any gasket material I've come across.

One method I've thought of for improving the seals is to apply a bead of furnace cement all around the sealing surface on the stove, then place a film of plastic food wrap (or wax paper ?) over the bead and close the doors until the cement has set. If the plastic sticks, it should burn right off on the first fire, leaving a snugger door seal. This might have to be done in stages, as the cement likes to begin setting quickly.

Likewise, the door latch had worn to the point that the lower door wasn't closing as tightly as it should... leaving both doors slightly loose. I've temporarily fixed that by placing a small steel spring clip on the movable arm of the latch that engages the fixed 'hook' on the door frame. A $.02 solution.

Peter B.

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[waynek]

I'm also more likely now to completely close the two stove draft controls (ash pit and front door), so that there's not as often a draft directed through or over the coals... which may help extend their life.


-----[/quote]

Peter B,

I am sure every Round Oak D model and chimney draft is different, but just wanted to say my extended burn times are only accomplished with ashpit and feed door drafts closed. My Round Oak D model has the original grate which is half slotted. At one time I considered plugging the slots, because when the ashpit draft is closed I could detect a minute amount of draft effecting the fuel. Rather than do that I just let ash and coals build up on the grate slots and the draft leak from the ashpit goes away. Even when I start a new fire I leave at least two inches of ash on the grates and allow the secondary draft in the feed door to ignite the kindling. From time to time I shake the ashes into the ashpit, but am careful not to loose the ash covering.

 

[Peter B.]

jackpine:

That statement of mine was a little misleading... I always close both ashpit and feed door drafts if I'm hoping for an extended burn, but typically leave them both cracked a bit when more heat is needed... at least I used to. As previously mentioned, I've had to put a restrictor in the secondary inlet to slow things back down. Without the restrictor, the fire liked to run about 550* (flue internal 12" from stovetop), even with manual drafts closed... a bit too warm (and fast burning) for normal use.

Ideally, I'd figure out some way to regulate the secondary intake, but I haven't 'gotten there' yet.

Peter B.

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[Peter B.]

I may be wearing out my welcome here, but I thought I'd add this detail...

Yesterday, I replaced the tired 1" thick no-name catalyst in my stove with a 2" finer honeycomb 'major brand' model.

The first burn is in progress this morning. Results aren't (by any means) conclusive yet, but first impressions suggest that the new catalyst restricts overall flow through the stove a good deal more than the old... allowing for a slower burn and somewhat reduced flue temperatures for a given stovetop internal temp (as observed previously). Currently, 450* and 1000*+ respectively. No visible smoke from the chimney.

Catalyst light off was quick (by comparison) and it glowed at a lower initial temp than the old. Right now, all drafts but the secondary are closed, the stove is very 'quiet' (no heating up or cooling down ticks or pings), and I assume the catalyst is chewing away on the volatiles.

So it would appear I've got a choice now - running hot on the secondary (with drafts slightly open), or closing up tight and letting the catalyst do its magic... at a slower burn rate. I'll be curious to see how well I fare with an attempted overnight fire.

Somewhat regrettably, we're having a warmish spell here in SW Wisconsin... and I can't extend the testing much longer without opening doors and windows.

Then again, that might not be such a bad idea given the stale beer and tobacco smoke stench that likely prevails here.

Peter B.

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[waynek]

Peter, do not worry about wearing out your welcome here on your stove experimentation. I for one, am all ears.

I am patiently waiting to purchase your first drop-in Round Oak stove upgrade. In fact I have a Model D - 18 backup stove standing in the corner that has not been fired in eight years. We can put the first off the shelf upgrade in that one.

 

[begreen]

I'd be curious to see how the burn times have changed with the secondary mod and then with the new cat.

 

[Peter B.]

I'd be curious to see how the burn times have changed with the secondary mod and then with the new cat.

BeGreen:

I'll be curious too... but the weather here is forecast to be mild for most of a week, and I don't feel I can trust any 'data' gathered unless or until it gets cold again.

Right now, just before heading out for a walk (in the balmy 35* outdoors), the indoor thermometer is reading 78*... and it's been holding (near) there for several hours. I'll have to let the fire burn out and start fresh when there's actually a 'demand' for heat.

Peter B.

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[karri0n]

Definitely can't wait to hear your conclusive results with the secondary and now the new cat. I REALLY like your gasket fab idea.


As for your question, I'm glad to say I did install my damper, and loaded up the stove at 8:30 last night. The wood is under seasoned, though FAR better than my last shipment. It took until about 10:00 to get the load really charred and gassing off well, but the last wood I had wouldn't even gas well until most of it was coaling. Since I actually started it at 8:00, I added in 2 more splits to the mostly full load, got it going, closed it down and shut the pipe damper. woke up to 65+ with enough coals to get it going again(first time ever with coals in the morning). I love the damper.

 

[Peter B.]

Definitely can't wait to hear your conclusive results with the secondary and now the new cat. I REALLY like your gasket fab idea.


As for your question, I'm glad to say I did install my damper, and loaded up the stove at 8:30 last night. The wood is under seasoned, though FAR better than my last shipment. It took until about 10:00 to get the load really charred and gassing off well, but the last wood I had wouldn't even gas well until most of it was coaling. Since I actually started it at 8:00, I added in 2 more splits to the mostly full load, got it going, closed it down and shut the pipe damper. woke up to 65+ with enough coals to get it going again(first time ever with coals in the morning). I love the damper.

karri0n:

That's great to hear... with some additional experimentation, I'll bet you can 'dial in' that stove much more to your liking.

By the way, though most dampers have 'pass through' holes in them, I believe folks here generally advise only to close the damper to about 45*... not fully shut. BUT, I figure it's a matter of whatever works for you. I think the only safety concern (for a fully closed damper) would be smoke leakage from the stove or pipe... which you should definitely be vigilant about while you're still 'new' to damper use.

It strikes me that EPA stoves are likely tested under extremely exacting conditions... yet those conditions may not include overdrafting situations... and clearly there are plenty of those in 'real life'. Stove manufacturers may not recommend dampers in their user's manuals, and of course, dampers are a bit of a nuisance (and not 'aesthetically elegant'), but in some cases they are pretty much a necessity.

--

It remains too warm here to burn flat out... or even continuously for that matter, so not much further to add about burn times and such. I really wish I had some furnace cement to go ahead with the door seals, but the cement MUST be in a tube, and it MUST be black, and I haven't been able to find that combination locally.

Peter B.

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[karri0n]

Lowes has Rutland black cement in the caulk section. It won't be listed as furnace cement on the outer tag for whatever reason, but it was next to the firestop and labeled as "draftstopping", but on the tube it was noted to be for sealing metal/mortar, black, and I believe rated for 2500 degrees.