# What causes cast iron woodstove to crack? Stove dealer says green wood has to do with



## SpiralAcacia (Mar 4, 2012)

Are you familiar with it?
I knew only about warping due to excess heating.

I had a 2" hole developing in my stove's baffle for the last 2yrs, but it is a 40 yo piece that had been lying in a yard on a rotten pallet for maybe 20 years. So it has it's excuses.
(I fitted the hole, hmmmmm, with the old sprocket from the saw....

But my cutting buddy's 3yo Jotul had me wondering.
It developed an open crack, 3" long in the middle of the baffle. Called the dealer.
Dealer says, "Do you burn green wood?"
So I said to my buddy. I think it's the generic "Not my fault" reply to costumers.

Or is it my bit of ignorance? What else causes cast iron woodstoves to crack?

Thanks

SA


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## Whitespider (Mar 4, 2012)

Maybe I don’t understand you correctly, or maybe I’m just ignorant of the “newer” stoves, or maybe what I think of as a baffle is something else. Are you saying the baffles are made from cast iron, not stainless?

Cast iron is very tolerant of heat, and repeated heating-cooling cycles, but it won’t last indefinitely. Over time cast iron will deteriorate and warp, swell, crack or just crumble. Overheating, to the point of glowing red, will shorten its useful life in a hurry… especially repeated overheating. With that said, I don’t understand what the burning of green wood has to do with it… except maybe because cast iron is a (relatively) porous metal it can hold moisture. I know that if you soak a piece of cast iron in water, and then subject it to rapid high heat, it can literally explode as the moisture expands faster than it can escape from the pores.

A casting flaw will cause cast iron to crack prematurely... but at 3 years old I wouldn't think you can blame it on that. A casting flaw will normally show up during the first dozen (or less) heating-cooling cycles.


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## oneoldgeezer (Mar 4, 2012)

It would seem to me that green wood wouldn't bother as much because it doesn't burn as hot as good dry. I think you're right that it is a "cop out" by the dealer.


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## BrokenToys (Mar 4, 2012)

####ty casting of the iron would cause warpage/blowouts as mentioned here already. If the stove was purchased new and the retailer has lame excuses tell him you've already contacted the BBB.


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## Como (Mar 4, 2012)

In 2 years, unless you have been grossly over heating it, sounds like a manufacturing defect.


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## SpiralAcacia (Mar 4, 2012)

Whitespider,
It's a cast iron, box and baffle, usual deal.

It seems no surprises, prolly a cop out by the dealer indeed. Thought maybe somefin' I was missing...

Thanks guys

SA


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## THE PLUMMER (Mar 4, 2012)

Its cheap low quality cast iron plain and simple. There are many cast iron boiler manufacturers on the market, and they all make some big claims. However its always the same brands that fail. Not all cast iron is the same. So when you have a Buderus , Burnham and they last 30 to 55 years compared to another unamed brand that has a hard time getting 15 years before failure. Stress cracks to errosion from cold shock or condensation over extended periods cause the failures. Much more difficult to do with a wood burning firebox. A good piece of german made or the American made cast iron will cost double of what the cheap CI cost, because there is a big difference in chemistry. So for you to have one fail in any amount of time is abnormal. Unless you have a 2 stage combustion your firebox will never see the extreme temps it takes to effect CI no matter how wet your wood is. It only takes about 850-920 degrees to get red Far from the 2000+ it takes to change CI. And you would have to shock it as well, spot heat like from a torch and water soaked CI, similar to what was mentioned above. I would agree you got a typical excuse hoping your not smart enuff to know any better.


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## Preston (Mar 4, 2012)

Yup, the dealer is looking for an excuse.


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## MacLaren (Mar 4, 2012)

Great responses guys. I learned a lot. Thnx.:msp_thumbup:


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## ray benson (Mar 4, 2012)

SpiralAcacia said:


> Are you familiar with it?
> I knew only about warping due to excess heating.
> 
> I had a 2" hole developing in my stove's baffle for the last 2yrs, but it is a 40 yo piece that had been lying in a yard on a rotten pallet for maybe 20 years. So it has it's excuses.
> ...



http://www.jotul.com/FileArchive/Fi...Woodburning product limited warranty 2012.pdf


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## Fred Wright (Mar 4, 2012)

Worked for 12+ years in a cast iron foundry, maintenance. We didn't make stove parts ~ valve boxes and manhole covers. One of our plants made castings for MTD. I learned about the process over the years.

Quality cast will last virtually forever in a wood burner if it's used as directed. This is why so many of your great Grandpa's potbelly and log stoves are still in service today. This is why you can get 200,000 miles or more out of a cast iron engine block.

We melted for pouring at around 2700°F, far above the heat a wood burner would produce. Where problems arise is poor metallurgy. Impurities in the heat and uncontrolled curing can result in a poor or brittle casting.

Much of the cast these days is coming in from China and India. There's little in the way of quality control and metallurgy over there. Anything that melts is charged in the furnace. OK for microphone stands, not great for wood burners. It's poured, cleaned, painted and sent here where it falls apart. That's sad.


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## Iska3 (Mar 4, 2012)

THE PLUMMER said:


> Its cheap low quality cast iron plain and simple. There are many cast iron boiler manufacturers on the market, and they all make some big claims. However its always the same brands that fail. Not all cast iron is the same. So when you have a Buderus , Burnham and they last 30 to 55 years compared to another unamed brand that has a hard time getting 15 years before failure. Stress cracks to errosion from cold shock or condensation over extended periods cause the failures. Much more difficult to do with a wood burning firebox. A good piece of german made or the American made cast iron will cost double of what the cheap CI cost, because there is a big difference in chemistry. So for you to have one fail in any amount of time is abnormal. Unless you have a 2 stage combustion your firebox will never see the extreme temps it takes to effect CI no matter how wet your wood is. It only takes about 850-920 degrees to get red Far from the 2000+ it takes to change CI. And you would have to shock it as well, spot heat like from a torch and water soaked CI, similar to what was mentioned above. I would agree you got a typical excuse hoping your not smart enuff to know any better.




Good info... Plummer.. 

I heated our house with a old 1940's cast iron wood furnace until 1991 when it finally cracked. I over heated the furnace with kiln dry oak lumber scraps from a company in town. Even then it would not have cracked. The pan of water on top of the furnace softened and the water went on to the case causing it to cool too fast. 

"Not all cast iron is the same"


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## THE PLUMMER (Mar 5, 2012)

You know gentlemen, this is the stuff that really burns me up, most of us take so much pride in what we do and what we buy. Especially in big purchases and toys. We don't have a problem spending a few extra dollars for a quality piece of iron, but far too many knock offs or markets flooded with cheap junk are getting thru as "quality" . What I fear most is china slowly poisoning us by hiding dangerous stuff in the products, we all know about the lead painted kids toys and the poisoned dog food, but what else is in this cheap metal that gets shoved on us. I repair way too many boilers that are 30+ years old with NO signs of slowing down, ( Burnham USA & Buderus & Viesmann) and I also get a bunch 10 year new junk and just think , things aren't built to last anymore. They make them to live as long as the average time a homeowner stays in 1 house. I wish consumers would research more on where there product is made. Unfortunately this too can be skewed, like water heaters. There are some brands that are labeled Made in USA , but actually they only get the AGA, ASME or UL stickers and then boxed in the USA. The only water heater made 100% in USA is Bradford White / Lochinvar right in Middleville Michigan FYI. Sorry for the rant.......


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## jags (Mar 5, 2012)

The better question would have been "does he burn wood?" - Yep....well thats the problem right there.

Wet or dry wood - cast doesn't care.


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## fubar2 (Mar 5, 2012)

Rapidly changing temperatures, especially hot to cold.


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## Preston (Mar 5, 2012)

Now y'all got me concerned. I'm starting to look for a standing stove for the fireplace, knowing it'll be cast, now how do I know if it's crap or American cast?


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## SpiralAcacia (Mar 5, 2012)

ray benson said:


> http://www.jotul.com/FileArchive/Fi...Woodburning product limited warranty 2012.pdf



Thanks Ray,
The link clears it's definitely under warranty, It's the baffle (clause A) and cast iron (clause B).

PLUMMER, you hit a spot, it's such a let down when you decide to pay more for QUALITY and you get MANURE with a posh sticker on it... REALLY disappointing !

So now some bits fell off it looks no good. It's at the rear of the baffle, along the middle of it, almost 4" long and maybe 3/4" at widest.
So I told my buddy he needs to tell his dealer he has been burning dry firewood that's symmetrical, sharp edges sanded off + each piece has local authority permit and number. Ashes kept for inspection at request.

Thanks for the input, everybody, I told the guy, "I know just where to ask" :msp_thumbup:

SA


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## 4seasons (Mar 5, 2012)

THE PLUMMER said:


> I wish consumers would research more on where there product is made. Unfortunately this too can be skewed, like water heaters. There are some brands that are labeled Made in USA , but actually they only get the AGA, ASME or UL stickers and then boxed in the USA. The only water heater made 100% in USA is Bradford White / Lochinvar right in Middleville Michigan FYI. Sorry for the rant.......


I was recently laid-off from a plant that did this same kind of thing. We shipped out a grill that said on the box "Made in USA" right next to an American flag and the shipping address in Greeneville, TN. Then in smaller letters right under that it stated "Grid made in China." My job was to pull the containers that had came from China to the different warehouses and to the plant to be unloaded. Almost every part used to put that Made in USA grill together came from China. The only thing they did at the plant was stamp the upper and lower dome, paint it, put it together, and box it up. And too top it off you had to speak Spanish to talk to anyone in the plant. So while the biggest print on the box was "Made in USA" what it should really say is:
Boxed in USA, by Mexicans, with the cheapest parts China could ship us. Unfortunately that is the way a lot of companies are staying in business. Big Box Mart demands that the be sold a product at a certain price point and the manufactures have to come up with a way to cut cost and still make a profit, or lose their biggest customer. Then sometimes companies like the one I worked for tell Big Box Mart, no we can't make it any cheaper, and lose their biggest customer. Then sales drop off and lay-offs follow.


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## Marc (Mar 6, 2012)

Metallurgically speaking, a brittle material like grey cast iron fractures when microscopic weaknesses, natural stress concentrations inherent in the material, enlarge into micropores under the load of applied stress. The micropores continually coalesce under the load which can be static for brittle materials leading to fracture initiation typically perpendicular to the applied stress.

Aren't you glad you asked?


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## Preston (Mar 6, 2012)

But why did it happen. What you say in how it happens.


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## Marc (Mar 6, 2012)

Preston said:


> But why did it happen. What you say in how it happens.



The applied stress was greater than the strength of the material.


*ta-da*


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## jags (Mar 6, 2012)

Marc said:


> The applied stress was greater than the strength of the material.
> 
> 
> *ta-da*



ie - "It broke".


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## cheeves (Mar 6, 2012)

fubar2 said:


> Rapidly changing temperatures, especially hot to cold.


I knew a guy in the 70's busted a 118 Jotul with some frozen dead oak. 2 main causes are cheap cast iron and frozen wood.


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## SpiralAcacia (Mar 16, 2012)

*Dealer says...*

News from The Front!

The dealer who sold the Jotul 602 wood stove to my friend emailed him an answer regarding the growing crack in the back of the baffle.
It goes to the tune of -
"I showed the pics to a colleague just to be on the safe side...
You'll have to buy a moisture meter, google it up...
The baffle damage and the over-all looks of your firebox is a definite giveaway that you've been burning firewood that's over 15% moist.
Continuing to burn over 15% moisture firewood will result in destroying the whole stove and it's the reason for VOIDING the warranty...
You best take your plate (i.e. Baffle - SA) to welder's shop to get it fixed up in a heat resistant way...."

Got to tell you guys, I've been wasting some time surfing the net trying to find SOMETHING to support this nonsense....
Even in Jotul's 602's User Manual only problem related to wet wood mentioned is bad burn, creosote build-up etc.
Only damage they mention there is from over-firing...

So my friend will try to talk some sense into the guy and then he needs to either small claims the guy or drop it.
Seems Jotul doesn't have an official dealership here in this neck of the woods, at least I couldn't find it on the web, and they don't really have an international address to whine to...
I actually think Jotul would be interested to know about a production flaw.



Thanks

SA


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## Como (Mar 16, 2012)

Should be with the warranty info.

I think they are in Maine.


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## ray benson (Mar 16, 2012)

Warranty is given by Jøtul North America, Inc.,
55 Hutcherson Drive, Gorham, Maine 04038 USA


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## fir (Mar 16, 2012)

The only thing that would crack cast iron besides casting flaw or poor quality is heating it up real hot and dumping cold water on it.


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## SpiralAcacia (Mar 17, 2012)

*Location...*

Hmmm, guys, I'm a little bit AWAY from Maine vicinity...

I'm from Israel, middle east :smile: 

Jotul have dealers for many countries but seems not for this one!
Maybe it's to small of a market, donnow...

SA


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## wkpoor (Mar 17, 2012)

Not sure how much use this stove has seen but cast iron baffles are known to wear out. Many new stoves have the ceramic baffle board which will survive heat better. Sure a cast iron stove will last nearly forever but not the baffle. In continuous use they last about 15yrs if made from good quality iron.


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## SpiralAcacia (Mar 17, 2012)

wkpoor said:


> Not sure how much use this stove has seen but cast iron baffles are known to wear out. Many new stoves have the ceramic baffle board which will survive heat better. Sure a cast iron stove will last nearly forever but not the baffle. In continuous use they last about 15yrs if made from good quality iron.



Exactly what the manufacturer says, it makes sense.
In the warranty Jotul mentions the baffle as 'consumables', but in this case the stove sees its 3rd winter when the crack appears...
Even 10 years sounds acceptable if not desired, but 2 winters and that's it...? Nah.

SA


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## jags (Mar 19, 2012)

SpiralAcacia said:


> You'll have to buy a moisture meter, google it up...
> The baffle damage and the over-all looks of your firebox is a definite giveaway that you've been burning firewood that's over 15% moist.
> Continuing to burn over 15% moisture firewood will result in destroying the whole stove and it's the reason for VOIDING the warranty...



Complete and utter BS. There is no fricken way. Mater of fact, wood with a higher moisture content will burn at a lower rate then the dry stuff. There is NO way that enough moisture could escape wet wood fast enough to create ANY thermal shock to the cast iron @ 5-600F. Period.

Glad it is not me in this situation.


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