Wood heater material

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I am new to the site and searched this but didnt find a direct answer. From my reading on the site i know there are a lot of knowledgeable people on here and would like to way some opinions. I was wondering  which material to use to build a wood heater in my shop. i have on hand a 4x8 sheet of 5/16" mild steel and i also have 2 4x8 sheets of 409 1/4" stainless i know the stainless would look nice but i dont know it how the heat transfer would be. i plan to fire brick the inside of the heater so i dont think heat fracture would be much of issue on the stainless.
Reply:I own an outdoor wood burner made by Central Boiler.  They offer both mild steel and stainless fireboxes.  I asked the same question and their answer was that they had measured less efficient heat transfer with the stainless, but they were obviously less vulnerable to the corrosion that comes from wood burning.I chose the mild steel firebox because it was cheaper and something that I can more comfortably repair on my own.My vote is for the mild steel - even 1/4" is pretty thick for the firebox, your material will be more than sufficient.  One nice thing about the thicker walls is that they will have a little more thermal inertia, will radiate heat longer than the thinner stuff.Hobart LX235Victor 250 Oxy-Acetylene Rig (welding and cutting)Bobcat 773F-350, 1999, 4x4, 16' 10K# trailerOutdoor Wood Burner - 10 cords/year
Reply:The stainless steel that Central Boiler and Crown Royal boilers use is not your run of the mill stainless steel. It has other alloys in it as well.Sounds to me like apex wants to build an air tight type stove for inside his shop. These stoves use MUCH less wood than an outdoor wood fired water heater. Your typical indoor airtight stoves are made from mild steel with some using a cast iron door.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Stainless steel doesn't conduct heat anywhere near as well as mild steel.http://www.engineeringtoolbox.com/th...als-d_858.html
Reply:I might go with the mild steel as well. You are going to fire brick line it, burn thru maybe not too likely. Castable refactory is good for parts that not shaped right.Better stoves are probably all cast iron. But I might think more along the line of a heat exchanger type design more than a conventional stove. Forced air cooling, distribution. Better wood burners use quick hot flames, lot depends on your fuel source, age, etc. Lot of designs heat and store it via some means, water, mass, etc. Might even think about forced air for burning and how to control temperatures. Ideas like build it into a masonry mass type situation. Bit of thinking out of the box.  Quick hot flame to heat a mass that then radiants for a long time. Long slow wood fires result in too many chimney fires.If you look at various commerical furnaces lots of ideas to copy.
Reply:me and a friend built an outdoor wood burner, we used 4ft and 5ft diameter 1/2" wall pipe, endcaps were 7/16 plate....tackleexperts.comwww.necessityjigs.comhttps://www.facebook.com/groups/mach...dingequipment/
Reply:One thing I did not mention is you got to make sure it does not stink, depending on your location. Lots of that wood burning equipment just plain stinks up the environment. Those outdoor furnaces can be in that category. Some places looking to ban them. The quick hot flames helps a lot in that regard.The other possible consideration along that line is you can set your self up for lawsuits from somebody claiming you damaged their health. I would study up on some of these type websites for ideas. Might even damage your own or other family members if done wrong. Folks with breathing problems can come after you big time.How to do gasification and burn very, very clean.http://woodboilers.com/wood-boilers.aspxYou can also look at the concept of pyrolysis where you burn something without enough oxygen to gasify the product and then burn that gas in a two step process by injecting air in another chamber. Lots of fluidized type bed processes might also be done in a home brew type design. But you want to understand it from a more science type based principles before plunging in. I had an old MB55 from Tarm for many years and ran it on both coal and wood. Just loved it. Wish I could have moved it. Their new stuff is wowzer. http://en.wikipedia.org/wiki/PyrolysisOn some of that welding stuff it is best to think a bit like a lawyer before thinking like a welder. What am I really getting into???
Reply:I'm not sure about health issues, but I can say that my insurance company will not ensure my house unless the wood stove has a UL number.  No UL number and if the house burns down I'm SOL.I'm not saying you can't build a safe wood stove on your own, I'm just saying that if you have insurance, you want to check with them what their requirements are.  Some insurance companies might just want to send an inspector of some sort over.Con Fuse!Miller Dynasty 350Millermatic 350P-Spoolmatic 30AMiller Multimatic 200Hypertherm PowerMax 1000G3Miller Maxstar 200DX
Reply:Thanks for all the input. snoeproe is right i am looking to build an air tight heater for the inside of my shop i was planing on just copying the wood heater that is in our house but i would like to change one thing i want a ash tray in it. our primary source of heat in the house is the wood stove but you have to pretty much let it burn out to clean the ashes out of it and then rebuild the fire this gets old during the winter. i have looked at several heater designs on here and like them but most are made of pipe and i dont have any on hand. but i still have time to decide they just started putting the frame of the shop up today. CosmicRambler thanks for thinking of the health aspects i live in arkansas and as far as i know(never checked) there are not many regulations on a wood burning heater here....also most of the neighbors burn wood.