DIY outdoor furnace

[Clif]

Seems like there was a topic on this before.  I would like to know more on building one.  Clif

[Dana]

 It was DangerousDan who built an underground outdoor furnace. The info was on the old hard drive. If you don't have time to wait for the restoration, instant message him.

[jokers]

I don`t think there is any rocket science in building a non-pressurized wood fired boiler, build a firebox surrounded by a water jacket and add a few controls depending on what features you want it to have.

Here`s a somewhat amusing anecdote. I used to sell Heatmor and one day while I was taking delivery of a few units the semi driver, who happened to be from northern Minnesota where they are built, asked how much people were paying for them and why they don`t just build their own? He rolled his eyes and stated that homebuilts are everywhere in northern Mn and that you rarely see one of these factory built models. hmmmmmmmm................

I haven`t gone to check for myself yet. Wouldn`t be surprised though.

[beenthere]

My wood boiler is from N. MN, and is like jokers says...just two rolled steel tubes, one inside the other...welded together. Only 'rocket science' on mine is a well formed cast iron air-tight door well engineered for the purpose. Then a draft opening with a damper that is opened and closed by a thermostat (default is closed). If ever the original fails, I will have a new one made at the local welding shop. Mine is pressurized to about 12-15 psi. Has controls similar to a hot-water heater, including the safety release.

Has been functional since 1975...had a new back plate welded in once. About a 9 gal water jacket and the 1400 sq ft home is easily heated in the coldest of winters. Only fire with gas when gone for a weekend or trip.

[Roy M]

Homebuilts are illegal here, not CSA approved.  Particulate emissions are the issue.

[Corley5]

Be sure to use the proper materials.  My factory built stainless unit was welded together with mild steel wire.  It began leaking the 2nd season.  The manufacturer not the distributor is sending me a new one    He's standing behind it even though it's not his warranty.  He built it to the distributor specs and they won't honor the warranty.  I think he should have known better than to use that wire but I'm getting a new unit so it's 

[jokers]

I`ve been talking with a few friends about building a few and my guiding priniciple is KISS, Keep It Simple Smarty!

I also believe that a cleaner burn will be achieved if the unit fires more frequently, as you have with a smaller water jacket. I like the forced induction that my Heatmor uses and would probably use that in my new units. I`m also thinking about shaker grates for coal, anyone got any experience?

[Corley5]

My boiler has shaker grates as does my Grandma's Heatmor    I wouldn't want one without them 

[jackpine]

By all means put shaker grates in the furnace. My Aqua-Therm does not have them and it is a real problem with ash buildup on the grates. I have to rake the ashes back and forth over the grates to get them to fall through as the slots in the grates are too narrow also.

Bill

[Don P]

I've wondered, how do any of these pass emissions, is it a different standard than say a woodstove?