Here are some comments from
purchasers and users of
Stainless steel is not corrosion proof but it is corrosion resistant. In some cases, against some chemicals, stainless steel is no better than plain steel. It is also true that some chemicals can reportedly leach the chrome out of stainless steel (if there is any - in that grade of stainless).
Ted Mooney, P.E.
We own a stainless model and after 5 years the 10 year warranty was a joke just try to collect. its a discarded junk heap is it the stainless I have been welding lots of steel stoves for pitting but never seen one crack .
Just to set the record straight on stainless steel, it doesn't work in an outdoor use. It can't account for the rapid temperature changes. I am only starting to get into the heating business and I already know that stainless steel is a nice concept but when you have a cracked water jacket and there is know way to fix it, don't come crying to me. Also I love reading about all these companies with there lifetime warranties who have only been in the business for 3-5 years, give me a break. As soon as one claim comes in they go bankrupt and your on your own once again. Mild steel is a metal that works and if you have half a brain to take proper care and daily maintenance of your furnace it will last you. Thanks for your time.
Definitely go with the mild steel when you buy an outdoor wood furnace. I've seen both in use and the mild steel will not have the corrosion problems that the stainless steel has. I currently own a (wood furnace) with mild steel and I can give my testimony that it has worked perfectly and has needed no maintenance or upkeep for any type of problems. I don't speak from a "metallurgy" knowledge, but from practical experience that has done me well.
I HAVE SEEN MILD STEEL UNITS, SIXTEEN YEARS OLD. UNDERSTANDING THE PHYSICS OF WHAT CAUSES CORROSION IN THESE TYPES OF METAL IS KEY. WATER ABOVE 175 DEGREES DOES NOT HAVE AVAILABLE OX. FOR CORROSION. MOST OF THESE UNITS RUN AT 180 - 185 DEGREES. 304 STAINLESS IS EXTREMELY PRONE TO STRESS CORROSION CRACKING - WHICH RESULTS FROM CHLORIDES IN THE WATER REACTING WITH THE NICKEL CONTENT OF THE STEEL. THIS IS NON-REPAIRABLE BY WELDING. 409 STAINLESS WILL GIVE YOU THE HEAT TRANSFER ABILITIES AND EXPANSION PROPERTIES OF MILD STEEL, IT IS A FERRITIC STAINLESS, SO THE SURFACE WILL TARNISH. THE CORROSION RESISTANCE IS STILL GREATER THAN MILD STEEL. ... KEEP IT SIMPLE.
NOTE from Shaver Furnace: ALL stainless steel gets stress cracks and
because it is so expensive, it is made very thin and so all of the
cracks eventually go all the way through and soon you have a pile of
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