Cracks in Sides of Harmon Mark III

Modern and vintage hand fired coal stove are similar to a wood stove and in some cases can burn either. They need to be regulated and fed by hand usually every 12 to 24 hours depending on your usage. They require no power to operate making them ideal for rural settings with long power outages.
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CoalHeat
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Joined: Sat. Feb. 10, 2007 9:48 pm
Stoker Coal Boiler: 1959 EFM 350
Hand Fed Coal Stove: Harman Magnafire Mark I
Baseburners & Antiques: Sears Signal Oak 15 & Andes Kitchen Range
Coal Size/Type: Rice and Chestnut
Other Heating: Fisher Fireplace Insert
Location: Stillwater, New Jersey

Post Sat. Nov. 17, 2007 8:37 pm

xackley wrote:Heat effected zone is the weakest point :)

Worst case scenario is a 3/32 sheet of mild steel to cover the whole side.


It can change the temper of the metal--am I correct?
Heating a circa 1832 farmhouse with a Harman Magnafire Mark I & a 1959 EFM 350 (heating DHW).
100% Oil Free!
"It's what we learn after we think we know it all that counts."

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coaledsweat
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Stoker Coal Boiler: Axeman Anderson 260M
Coal Size/Type: Pea
Location: Guilford, Connecticut

Post Sat. Nov. 17, 2007 10:50 pm

It will only take one fire to normalize it. :D
Nothing is impossible for people who don't have to do it themselves.

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titleist1
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Posts: 4404
Joined: Wed. Nov. 14, 2007 4:06 pm
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite
Location: Cecil County, MD

Post Sun. Nov. 18, 2007 8:24 pm

The weld did not crack, the steel on the side of the stove cracked along the weld line. It looks to me like the warp of he baffle pulled in each side enough to crack the stove. As someone else mentioned, the baffle weld was stronger than the sheet metal.

I inspected the baffle and noticed it is compromised. There are layers of the steel that have flaked off the top of the baffle. Its not just slag from the years of use, the steel is actually thinner toward the middle of the top of the baffle than at the edges. I am guessing that changed its ability to handle the temperature without warping. I think to correctly fix this the baffle would need to be replaced as well as the cracks on the side. I have already ordered the replacement stove. In looking at the Mark III at a dealer, I noticed there is really nothing different at all from the new stove to our 15 year old one.
I drive a VW TDI, heat my home & workshop with two coal stokers and have two vintage JD diesel tractors....
The EPA just loves me!!

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CoalHeat
Site Moderator
Posts: 8327
Joined: Sat. Feb. 10, 2007 9:48 pm
Stoker Coal Boiler: 1959 EFM 350
Hand Fed Coal Stove: Harman Magnafire Mark I
Baseburners & Antiques: Sears Signal Oak 15 & Andes Kitchen Range
Coal Size/Type: Rice and Chestnut
Other Heating: Fisher Fireplace Insert
Location: Stillwater, New Jersey

Post Sun. Nov. 18, 2007 9:00 pm

Based on your description of the condition of your present stove, I would replace it as well. I would be more comfortable with a new stove burning in the house.

I'd probably still keep the old one, though, repair it and use it in an outbuilding or garage.
Heating a circa 1832 farmhouse with a Harman Magnafire Mark I & a 1959 EFM 350 (heating DHW).
100% Oil Free!
"It's what we learn after we think we know it all that counts."

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Yanche
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Posts: 3032
Joined: Fri. Dec. 23, 2005 12:45 pm
Stoker Coal Boiler: Alternate Heating Systems S-130
Coal Size/Type: Anthracite Pea
Location: Sykesville, Maryland

Post Sun. Nov. 18, 2007 9:11 pm

titleist1 wrote:The weld did not crack, the steel on the side of the stove cracked along the weld line. It looks to me like the warp of he baffle pulled in each side enough to crack the stove. As someone else mentioned, the baffle weld was stronger than the sheet metal.

I inspected the baffle and noticed it is compromised. There are layers of the steel that have flaked off the top of the baffle. Its not just slag from the years of use, the steel is actually thinner toward the middle of the top of the baffle than at the edges. I am guessing that changed its ability to handle the temperature without warping. I think to correctly fix this the baffle would need to be replaced as well as the cracks on the side.
Don't junk your old stove. Call Mr. Bunnell the welding instructor at your local Cecil County School of Technology. If they are like most vo tech schools they are alway looking for repair projects.
Yanche
Alternate Heating Systems S-130
Stoker Boiler burning Anthracite Pea Coal

greg white
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Location: Michigan

Post Fri. Nov. 23, 2007 8:29 am

Sad to hear Harman got sold,new owner,cheaper made product my guess.
I have a 1983 build stove(Harman SF150) in my shop,The welder signed his name on the bottom of mine with his welding stick.
I have a Harman wood stove(top loader)in my house,I am very happy with both stoves,and finally my wife likes the stove in the house cause of ease of loading,now I will be looking for cracks :idea: :shock: I do not have baro damper on the coal stove,that might help with the "too hot someday burn".
BOT,I think and believe a good welder can fix your crack,I second the drill holes at the end of cracks,it helps end the stress line.
GW
Harman hand fed SF 150 in the shop(my house)

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bksaun
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Posts: 966
Joined: Sat. Oct. 28, 2006 9:24 am
Stoker Coal Boiler: Hybrid, Gentleman Janitor GJ-6RSU/ EFM 700
Hand Fed Coal Stove: Hitzer 503
Coal Size/Type: Pea Stoker/Bit, Pea or Nut Anthracite
Stove/Furnace Make: Hitzer/ EFM-Gentleman Janitor
Stove/Furnace Model: 503 Insert/ 700/GJ-62
Location: Hustonville, Ky

Post Sat. Mar. 15, 2008 11:24 am

Titleist1,

Did you get the stove fixed?

BK
"Corn Stoves", It is morally wrong to burn something you can make into Whiskey!

BK

driz
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Joined: Mon. Jan. 28, 2008 12:19 am

Post Sat. Mar. 15, 2008 4:52 pm

Here is where you go with weld questions. These guys can tell you how to weld a noodle to a pancake and do it right. They also will tell you which process or what to avoid. Sign up and pix would be helpful as does descriptiion of the metal. http://www.hobartwelders.com/weldtalk/ Personally I wouldn't bat an eyelash about welding a stove of any sort. You should see the front axle of my old Ferguson tractor. It sits on a rotating pin and was split diagonally across decades ago as its a weak spot. They brazed that puppy in a forge by the look of it and it looks like a great big glob of frosting. Whatever they did it worked as I beat the snot out of the thing. You can literally weld any steel or metal product using the right process. I always like the idea of lining the inside edge with a large steel plate as it just has to improve strength and steel is easy and cheap to fabricate like that. Nothin to it but I wouldn't do anything till I got word from the dealer that it is your problem, not theirs. Chances are though that if its old the fix is up to you .

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titleist1
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Posts: 4404
Joined: Wed. Nov. 14, 2007 4:06 pm
Hot Air Coal Stoker Stove: Harman Mag Stoker (old style) one in basement, one in workshop
Hand Fed Coal Stove: Harman Mark III on standby for long power outages
Coal Size/Type: Rice/Anthracite; Nut/Anthracite
Location: Cecil County, MD

Post Mon. Mar. 17, 2008 10:45 am

No I did not get the stove fixed. I did not trust the integrity of the steel on the sides any longer and did not want to have to worry about more cracking (maybe some that I wouldn't be able to see) and smoke / CO problems. The internal baffle would have had to be cut out and replaced as well since it had flaked away and was very thin in spots.

I replaced it with another Harman Mark III and after two months had to get a weld repair done to the shaker arm linkage. It was covered under warranty but Harman & the dealer didn't want to deal with arranging for a welder to come out and fix it, they told me to get it fixed and submit a bill which I did. After about 3 weeks I am still waiting for payment. We'll see how many phone calls and letters it will take. I am going to bother them until they pay. It is a matter of principle now. My attitude is that they charge top dollar for their stoves so I am going to let them pay to fix it.
I drive a VW TDI, heat my home & workshop with two coal stokers and have two vintage JD diesel tractors....
The EPA just loves me!!

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