Stainless Steel Woodstove ?

Welcome.

Plate steel stoves already last forever. There isn't exposure to much in the way of corrosives. Anything in the smoke is carried out with the water vapors and up the chimney. It can condense on the inside of the chimney, which is why they are made of stainless.

As for your Fisher, check out the classic stove forum. Great Fisher sticky at the top. Start a new thread. A totally different subject gets more answers in its own thread.

A stainless stove would look very classy, but what a PITA stainless is to keep looking clean. Shows every print, every mark. WD40 is a good cleaner for stainless, even brushed stainless, but keep it handy 'cause you'll need it often.

jeepin1121 said:

Anyone ever heard of one being made from stainless steel ? Would the reason for them not to be available be weight and cost ? Any other thoughts on the matter ?
Also any possible way someone could post a picture of the internal part of a PAPA BEAR FISHER ? so as the plate can be seen ( plate that the gas has to travel under thru the fire to get out the exhaust...hoping I stated hat correctly

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Stainless is nearly identical in density as mild steel so weight is not an issue. Cost definitely is, stainless is about 3.5 times higher than mild steel.

Also stainless has about 1/3 lower thermal conductivity than mild steel. Probably not ideal for a stove.

Stainless is very good for internal stove parts, the baffles I made for my stove are made out of 1/4 stainless. The first one I made was made from 1/4 diamond plate and it warped badly.
The stainless steel is holding up just fine.

jeepin1121 said:

Anyone ever heard of one being made from stainless steel ? Would the reason for them not to be available be weight and cost ? Any other thoughts on the matter ?
Also any possible way someone could post a picture of the internal part of a PAPA BEAR FISHER ? so as the plate can be seen ( plate that the gas has to travel under thru the fire to get out the exhaust...hoping I stated hat correctly

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You could make a stove out of very thin SS....or parts for one.
Stainless has been used at times, but it is often overkill. Many stoves and furnaces use sheet metal - probably gavalume, which is similar to what is used for the bodies of automobiles. The old Efel Kamina stoves as well as ashley, king and many others were made from sheet metal as light as 22 gauge!

jeepin1121 said:

Realstone said:

A stainless stove would look very classy, but what a PITA stainless is to keep looking clean. Shows every print, every mark. WD40 is a good cleaner for stainless, even brushed stainless, but keep it handy 'cause you'll need it often.

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thanks for the input...not really worried about classy look lol it will be used in a large shop and I happen to have some stainless to make it from

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Save the stainless for now. You may well devise a suitable use for it eventualy, but a wood stove isn't it. Just the reduced thermal conductivity alone excludes it.

I would avoid using stainless steel in a wood burning appliance for several reasons. As mentined above it does not transfer heat nearly as well as plain steel or iron. It is a lot harder to weld properly and tends to be more brittle than plain steel (can lead to cracking). A SS bright metal polished external finish it is not going to radiate as well as a black finish will. Also as mentioned above it is a LOT more spendy than other types of steel. I would avoid it even in an OWB, where it has been commonly used. Use a non-corrosive water addative in a boiler and even mild steel will not rust. Inside the firebox, creosote does not interact with, rust or corrode steel much, so SS does not have much of an advantage given the options out there for using plain Jane steel.

jeepin1121 said:

Anyone ever heard of one being made from stainless steel ? Would the reason for them not to be available be weight and cost ? Any other thoughts on the matter ?
Also any possible way someone could post a picture of the internal part of a PAPA BEAR FISHER ? so as the plate can be seen ( plate that the gas has to travel under thru the fire to get out the exhaust...hoping I stated hat correctly

Click to expand...

About 15 years ago I was in Finland (Sauna capitol of the world). I go every 5-6 years. I met a professor of mechanical engineering who had a summer cabin on a lake which had a sauna right on the water. He had had his students build a SS sauna stove as senior thesis. I think he taught at the University of Helsinki. You might try contacting them for the write up of that effort.

Interesting opinions on the finish of stainless steel. Stainless is not always shinny, brushed, or polished. Stainless can be had in any finish that mild steal comes in, in conjunction with how it is formed and the specific make up of the material. Stainless would not be my first choice for a wood stove due to the tendency to warp when heated. I have about 3000+ hrs. of experience in the field of stainless steel equipment fabrication and by no means consider myself to be an expert. I do however know what it is to build all things stainless. A wood stove could be built using stainless but it will discolor severely, warp, and generally be a pain. The thermal conductive difference is negligible, stainless stays really hot for a long time after welding. Mild steel may cool a bit faster but in my experience not much.

I did not want to get too technical, but I feel the need for some clarification here. Note that I do not weld steel, and I am just an engineer with tabels and charts for materials and metallurgy, especially steel as it is used so much in everything. There are indeed many types of SS out there with different properties. However there are several properties of SS that make it undesirable in using for a firebox from an engineering standpoint, other than its significantly higher price. Most types of SS have a higher coefficient of thermal expansion which is why it will warp or change dimensionally more than regular steel (from the fire in the unit and from being welded). Unless you use something like SS 430 which has about the same thermal expansion as mild steel (say 0.25% carbon steel). SS is used in a lot of Hx type devices as it resists corrosion well, and far better than regular carbon steels do. However in a flat plate collector SS is typically plated or bonded to other metals that have far better heat transfer, such as copper. The thermal conductivity for SS is significantly less than for mild steel: 16 (W/m-C) for SS 316, vs. 54 (W/m-C) for mild steel. Compare them to copper which has excellent heat transfer properties at 388 (W/m-C). SS is also less ductile (or less elastic) than mild steels. That means that mild steel can bend and stretch more before breaking than SS, and thus is less brittle than SS, and why SS tends to crack more than mild steel when used in things like OWBs. Finally the specific heat is different between SS and mild steel; the specific heat for SS 316 is higher at 502 (J/Kg-C) vs. 465 (J/Kg-C) for carbon steel, which is why SS stays hotter longer when it is being welded. Metals in general have low specific heat values, meaning they heat up pretty fast. However, with higher specific heat SS takes more energy to heat up and retains the energy longer when cooling down, as compared to mild steel. Just a point that specific heat should not be confused with thermal conductivity. Also if you want a place to store heat, steel is not a very good option. Water is much better for that. Water has roughly 10x the specific heat capacity of steel.

StihlHead said:

... thermal conductivity for SS is significantly less than for mild steel: 16 (W/m-C) for SS 316, vs. 54 (W/m-C) for mild steel. Compare them to copper which has excellent heat transfer properties at 388 (W/m-C). ...

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So the real question is what would it take to make a stove from copper!? Now, THAT would be quite the machine!

Not an engineer nor do i drive trains. But i do repair aircraft which entails experience in riveting. So if were gonna build a stove from copper i want to rivet the thing together. Copper rivets should do the trick. I bet its gonna look awesome after its been hot. or maybe not now that i think of it copper gets kinda ugly when it gets real hot. Dont even think silver solder or some form of welding (i dont think anyone welds copper but im probably wrong) cuz riveted joints all around would look killer. So who is gonna provide the copper plate ooooo thats gonna be expensive. OK so to cut costs i will rivet it for free. Can probably come up with some rivets too.

jeepin1121 said:

Thank you all for sharing your wealth of knowledge and opinions , I do appreciate it very much . That said I have already scrapped the idea if the SS stove and found a fairly LARGE woodstove on CL . Just picked it up Monday night hope to have it all hooked up to burn the rest of this winter then clean and paint and all over spring / summer .

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What stove? Pictures or it didn't happen! ;-P

Stove or boiler made out of copper? Egads... that stuff is $4 a pound for scrap. I just used it as an example, as it is known for its excellent thermal transfer properties. If you want the best in heat transfer, why not go with Silver? That is 418 W/m-C. Of course at $30/oz., that will be reeeeely speeeeeendy!

They used to make hot water heaters out of copper though. I have a friend that has several in his hot water heater museum in Monterey, CA. It has a solid tank, no rivets, solder seams or welds. Aluminum is the metal of choice for a cheap solution with good heat transfer qualities, for that reason it is common in cookware. Aluminum comes in fourth in the best heat transfer in metals (after gold) with 193-250 W/m-C, depending on the alloy. Gold is 315 W/m-C. Imagine that? A gold firebox Mega spendy!

Bone1099 said:

Not an engineer nor do i drive trains. But i do repair aircraft which entails experience in riveting. So if were gonna build a stove from copper i want to rivet the thing together. Copper rivets should do the trick. I bet its gonna look awesome after its been hot. or maybe not now that i think of it copper gets kinda ugly when it gets real hot. Dont even think silver solder or some form of welding (i dont think anyone welds copper but im probably wrong) cuz riveted joints all around would look killer. So who is gonna provide the copper plate ooooo thats gonna be expensive. OK so to cut costs i will rivet it for free. Can probably come up with some rivets too.

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Copper can be readily TIG welded. Due to it's high rate of thermal condutivity though, large amounts of welding current are needed. Freshly stripped electrical wire makes a good filler rod for copper.

This post is FYI only, steel makes a good wood stove.

dune,
Sounds like you are familiar with copper welding ?
Done a bit of TIG myself but not copper so......what type
of shielding gas is required ?
Helium ?
rn

rustynut said:

dune,
Sounds like you are familiar with copper welding ?
Done a bit of TIG myself but not copper so......what type
of shielding gas is required ?
Helium ?
rn

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Helium would be better, if you could get it. Argon is fine though. I weld mostly silicon bronze, 94% copper IIRC, but have had to repair some copper water cooled exhaust manifolds.

high alloy bronze welds very well too...kind of like stainless steel, with the main difference being the need to closely moniter interpass temps. Not nearly as bad as brass though.
Brass to me is the most difficult metal to weld. Especialy the low alloy stuff. Too much lead and zinc.

At $4/lb scrap, you could still have 300-400 pounds of copper in your stove for a reasonable 1200-1600 bucks...about the average price for a new steel stove. Though that would assume you could find scrap plate copper or some other usable shape/size - which might not be terribly likely. I suppose with enough doing, a person might be able to have a steel firebox with a cast copper top. Though a riveted outer shell would have some amazing appeal.