building a woodstove from sheet steel... looking for designs or thoughts

[ken morgan]

So my current wood stove is a little chinese jobby that takes nothing longer than about 14" and about three (3) 6" in diameter logs. I have decided this spring to build my own wood stove.

Back ground: vacation cabin on the flanks of fuji. average low in the three coldest months is about 2 Fahrenheit and the cabin is not well insulated cost to insulate more is prohibitive as I would either need to strip the siding and replace it along with the insulation, or strip the interior paneling and replace it after adding insulation. not to mention the cabin has huge glass sliding doors covering 90% of the south facing wall and 40% of the east facing wall.

the little chinese stove will heat the house to 68 degrees running full blast, it is just so small that it only holds that temp for about 2 hours before it needs to be reloaded. so my idea is to make a new stove that will hold enough fuel to run 4 or 5 hours or longer. All the adds I see for stoves like the Jotul series all claim 7 to 8 hour burn times (is this true or advertising hype?)

After reading about reburners and converting normal stoves to reburning, my first thoughts were to build a reburner. Then after reading some more the consensus seemed to indicate that the reburners while burning cleaner and producing plenty of heat seemed to go through wood faster due to there design, as well as having problems with producing and then burning off a bank of coals.

I also read some about stoves with grates in the bottom with a secondary air feed on the bottom that burned the coals better and allowed for an ash tray to easily clean the ashes out. decisions decisions....

I have both tig and mig capabilities in my home shop so welding and fab is not an issue. I was considering 7/16" steel plate for the top of the stove and 3/8" for the sides and bottom. I have seen plenty of plate steel stoves in my friends houses that were made of 3/8" (factory made of course) so I would think that a slight overbuild will be safe.

I will update this thread more later, time to go to work. anya suggestions on design or any threads that you are aware of that might not pop up on a normal searach please link

 

[Marine5068]

Hey Ken,
Sounds like a nice cabin indeed.
I would look for a good large stove and price it out first before making one.
Just say that because the new secondary-burn woodstoves are a far cry from older stoves.
My Drolet HT2000 burns for ten hours on one load of hardwood and can easily heat my 2400sq ft home.
I'm a welder too, but for the $1500 cost of the new stove, I just got it delivered to the front door and moved it into place to replace an old and tired Century stove that was way too small for the job it needed to do.
I would say buy one as big as possible and then you can work on insulation and sealing the place up along the way.
Good luck. Stay warm.

 

[ken morgan]

here in japan a jotul F600 starts at 5800.00 USD what do they run in the states?

 

[ken morgan]

Jotul F600 on yahoo think ebay,a little cheaper than retail by about 20%
http://page.auctions.yahoo.co.jp/jp/auction/194229365

 

[ChoppyChoppy]

Most stoves are 1/4" at most. 3/8" will make for a HEAVY stove!

 

[IyaMan]

here in japan a jotul F600 starts at 5800.00 USD what do they run in the states?

If you want some snazzy Scandanavian stove, certainly you'll pay through the nose in Japan.

Save yourself the headache of making proper air flow baffles and consider a domestic stove. A fat Honma stove with secondary combustion, comparable in size and heat output as that Jotul, runs about $1700 (200,000yen)
http://www.honma-seisakusyo.jp/shopdetail/018000000007

 

[Duane(Pa)]

3/8" Plate except doors, which should have been.....

 

[ken morgan]

If you want some snazzy Scandanavian stove, certainly you'll pay through the nose in Japan.

Save yourself the headache of making proper air flow baffles and consider a domestic stove. A fat Honma stove with secondary combustion, comparable in size and heat output as that Jotul, runs about $1700 (200,000yen)
http://www.honma-seisakusyo.jp/shopdetail/018000000007

Iyaman, I have a honma right now, but it is one of the dinky models....I have never seen anything much larger I mean i might see a honma that is like 15% or 20% larger than mine but thats about it.....got any links? their hompage is a bit difficult to read and my wife will not help...any thing that costs money she refuses to help with

sorry just realised you posted a link...I am on brain dead mode today after work....will check it out.

 

[ken morgan]

yeah even that is a bit out of my price range....I mentioned the Jotul because one of my neighbors has one and it is a nice piece of gear, not something that i would ever buy though unless it was used and therefore cheap. I can but the plate steel laser precut to dimensions and weld it up for about 600ish give or take, I can even put windows in it as i found a place in the states that custom cuts wood stove glass, I ordered form them to replace the broken panes in my current wood stove and the quality was GTG so i could make any size front glass I want and just order from them again. My thoughts was to copy the door design and air flow controls of my current stove and just build a box with a reburner to a larger size.... currently i run a 106mm (little over 4") and i get really good draft (really good) it might be too small for a larger stove, but I would be willing to play with it. If I had to replace I could, it would only be another grand or so for the pipes.

 

[ken morgan]

View attachment 566381
3/8" Plate except doors, which should have been.....

duane, did you weld that one up yourself? does it reburn? Does reburn save fuel, put out more heat, or cause you to burn longer....or is it just an epa thing designed to save the trees...(the ones I want to burn)

 

[IyaMan]

The huge Honma HTC-90TX is cheaper here:

Rakuten $1450 (164,000yen) http://product.rakuten.co.jp/product/-/468059779fc98f0192c77655c7a60b1e/
Yahoo $1450 http://store.shopping.yahoo.co.jp/safety-cushion/yk3198.html?sc_e=slga_pla
Amazon $1500

They all do free shipping to Kanto area, if that includes you.

Though, do you really need such a massive stove? Its rated for 60-75 tsubo (120-150 tatami), which is about 200-250sq meters or about 2100-2700 sq feet. That's a big space... and a lot of wood!

Also, the slightly smaller HTC-80TX is about $100 cheaper at any of these places and rated for 40-50 tsubo (1400-1800sq ft), and the HTC-60TX is also rated for 40-50 tsubo but takes a slightly shorter log than the 80TX and goes for about $1100.

 

[anlrolfe]

Secondary air inlet is typically unregulated and ensures higher efficiency at lowest damper setting but will usually decrease overall burn time.
You will be hard pressed to fabricate a home build that burn as efficient as an engineered stove.
As far as efficiency, I believe you will have better luck with a long narrow design and baffle similar to a Jotul 118 or Fischer ### Bear series
There are several wood stove forums and YouTube that show modification for secondary combustion

https://www.**********/images/uploads/Bear_VI_Series_Early_Manual.pdf

 

[ken morgan]

The huge Honma HTC-90TX is cheaper here:

Rakuten $1450 (164,000yen) http://product.rakuten.co.jp/product/-/468059779fc98f0192c77655c7a60b1e/
Yahoo $1450 http://store.shopping.yahoo.co.jp/safety-cushion/yk3198.html?sc_e=slga_pla
Amazon $1500

They all do free shipping to Kanto area, if that includes you.

Though, do you really need such a massive stove? Its rated for 60-75 tsubo (120-150 tatami), which is about 200-250sq meters or about 2100-2700 sq feet. That's a big space... and a lot of wood!

Also, the slightly smaller HTC-80TX is about $100 cheaper at any of these places and rated for 40-50 tsubo (1400-1800sq ft), and the HTC-60TX is also rated for 40-50 tsubo but takes a slightly shorter log than the 80TX and goes for about $1100.

My square footage is not that great, but my beso has shyte for insulation and leaks air like a sieve. some fo these I can address next year in the summer, others I cannot as it is cost prohibitive. my current stove gets the house hot enough, (20 celcius) just not for a long enough period of time. If i can stretch it out to an honest 4 or 5 hours of steady temp, then it would be long enough that we would not have to wake up in the middle of the night to restock it (we need to do this x 3 times at night....IE: I restock stove at 2000, wife and kids go to sleep at 2200, I restock then with some medium wood. I stay awake reading or drinking or both until 2400 and restock with Kashii (Oak) or kunugi (differnet type of oak) . by 0200 or 0300 we are down to coals and house temp has dropped to about 15 Celcius my wife wakes up sometime in this period and restokes with Oak and at 0600~0700 its my turn to do the same. I want to sleep in on weekeends....we have the kerosene stove set to turn on at 0400 but I am trying to minimize its use due to cost of kerosene.

I would be happy if the stove would hold temp until 0600 or so then the kerosene heater can take over and would not cost that much.

Secondary air inlet is typically unregulated and ensures higher efficiency at lowest damper setting but will usually decrease overall burn time.
You will be hard pressed to fabricate a home build that burn as efficient as an engineered stove.
As far as efficiency, I believe you will have better luck with a long narrow design and baffle similar to a Jotul 118 or Fischer ### Bear series
There are several wood stove forums and YouTube that show modification for secondary combustion

https://www.**********/images/uploads/Bear_VI_Series_Early_Manual.pdf

I will lookup the specs on these stoves a bit.

 

[ken morgan]

The huge Honma HTC-90TX is .

have you seen one of these?

http://page10.auctions.yahoo.co.jp/jp/auction/m192963041

one of my neighbors uses one of these he is heating a single story with loft so the heat rises...but I think he only gets about 3 hours of burn..might be that he has to run it harder due to heating the loft..... my place is single story low roof older japanese style

 

[ken morgan]

OK ignore that link...it looks like my friends but is half of the size....damn Yahoo...

 

[IyaMan]

If you want a long burn time, obviously the stove needs to hold a fair amount of wood and have good air-flow controls. If you're looking to get 8+ hours of burn for less than a grand, you'll be hard pressed to find such a stove which offers that just about anywhere, not just in Japan. So maybe making your own could be a low budget answer, though you'd be wise to find as much info as possible before starting. Certainly a good degree of satisfaction can come from making things yourself, but do also add into the cost all the time, effort, and headache you may encounter.
And remember, you get what you pay for.

 

[ken morgan]

If you want a long burn time, obviously the stove needs to hold a fair amount of wood and have good air-flow controls. If you're looking to get 8+ hours of burn for less than a grand, you'll be hard pressed to find such a stove which offers that just about anywhere, not just in Japan. So maybe making your own could be a low budget answer, though you'd be wise to find as much info as possible before starting. Certainly a good degree of satisfaction can come from making things yourself, but do also add into the cost all the time, effort, and headache you may encounter.
And remember, you get what you pay for.

yes that is sage advice. I kind of like the looks of those fisher stoves. basically they are the same design as my current stove but much much larger. My current stove is so old that I cannot find any literature on it at honma, but Iknow for a fact it is in the 10~15 or 15~20 tatami range stove. If I could get the same design but with 4 x the fuel capacity and good air controls I think it can be done......I just do not have 1500 cash any time soon. with taxes, and other already planned projects I am tapped out for big purchases for at least a year maybe two. I have emergency funds but I dare not tap them for something like this.

 

[IyaMan]

High capacity, high heat output, low price
http://www.honma-seisakusyo.jp/shopdetail/016000000004/016/O/page1/recommend/

takes 22" logs, heats 40-45 tsubo (1500-1600 sq ft)

No, its not thick cast iron, but flash-heat stoves like this get hot really fast, so if it goes out overnight, it'll be pumping out the heat within 5 minutes of re-lighting. Also good if you only visit your place on weekends, as I'm sure its frigid upon arrival. Unlike a cast stove, this'll initially heat the house from sub-zero temps up to something normal much much quicker.

 

[IyaMan]

even cheaper on Rakuten (18,900yen / $165)
http://product.rakuten.co.jp/produc...b1e00f63906d1934b35bf95a868fa0&scid=s_kwa_pla

 

[ken morgan]

so after running back and forth (mentally) on this I have decided to go through with building one myself. I have managed to piece together the basic designs of the fisher stove lines form the 70's and the 80's. It seems that the design allows for a long burn time with multiple sizes depending upon size of space that needs to be heated. that coupled with the ****** construction of my house means that even though my house is less than 900 sq ft. I am building a unit for a 1200+ sq ft house.

first step was to deal with the door and flow controls. i had a line on a double door set from ebay, but it fell through while I waited on some answers form the ********** website....I was trying to buy a single door from there and passed on the double door set from ebay. my mistake the idiot that was offering doors on the hearth never answered any pm's or posts....I think he tossed his items up purportedly for sale so he could bid on the ones on ebay and stump everybody that might bid on the other ones...**** i hate collectors....what the hell you need 70 different doors for a wood stove for?

I ended up bidding on a door for a jotul that I think will serve, thought that is debatable. i might need to modify it to get it to flow enough who knows. I have an order in for sheetmetal, pre-cut according to the plans I got (and then adjusted for local materials. we will see what happens. my plan is to build this and to test it over the summer outside with a 15" single wall stack on it and if it appears safe I will install it prior to the winter.

there is some debate about chimney flue sizeing. currently I have 106mm flue (4.2") and if it will flow enough. currently it flows enough to keep the hous warm in the coldest months, t is just the stove does not hold enough wood to with its flow design to last the night. my thoughts are that if it is big enough to heat the house from cold, it is big enough to keep the house warm over the night just maintaining. thoughts on that?