This is a home made arch and stainless steel pans purchased from ebay. The large pan measures 2'x4''x7", and the prewarmer pan measures 2'x12"x6". The evaporator pan developed holes when I left acid sit in the pan too long. They have been welded, and to my knowledge there are no leaks. I do not know the gauge of the steel, but it is extremely sturdy, maybe 18 gauge? The arch is made from a 275 gallon fuel tank, welded, with a fire and separate ash pan door. Ash pan door does not close completely due to warping. The firebox is lined with ceramic wool, some steel, and firebrick over that. This was built 5 years ago, but not used last year due to a health incident, and did not use it this season. (I bought a 2x6 evaporator made by a craftsman to use instead.) With a good fire, we could evaporate about 10 gallons of sap an hour. Baffles were set up in the rear to create turbulence and keep the sap boiling. The exhaust stack opening is 7". It's late in the season, should have posted this earlier. Feel free to make an offer. This is located in Titusville, Pennsylvania, and is for pick-up only. Thank you for viewing this ad.