Luck was on my side!

[BCPP]

Boiling off the last 50gal of sap in the head tank yesterday as temp was heading for 60's. It was also really windy. Just as I was finishing up, I'd stopped stoking fire and was just waiting for coals in arch to burn down, there was a large gusts of wind and I hear a crack and crash overhead. The wind had broken off the evaporator stack at the roof line and sent it crashing to the ground. Luckily by this point it was only hot air coming through. Dont want to think about what might have happened if that guest had been an hour earlier!

Looking at the aftermath it appears the top flange of the insulated section of pipe that passes through the roof had completely rusted away. I thought it was supposed to be ss. The galvanized upper section that fell is still in great shape.

Now to try and find a 2' section of insulated pipe that has the same stack diameter and same outer diameter so it fits through all the holes. I think they stopped making this - guess now I know why!!

[In da bush]

Boiling off the last 50gal of sap in the head tank yesterday as temp was heading for 60's. It was also really windy. Just as I was finishing up, I'd stopped stoking fire and was just waiting for coals in arch to burn down, there was a large gusts of wind and I hear a crack and crash overhead. The wind had broken off the evaporator stack at the roof line and sent it crashing to the ground. Luckily by this point it was only hot air coming through. Dont want to think about what might have happened if that guest had been an hour earlier!

Looking at the aftermath it appears the top flange of the insulated section of pipe that passes through the roof had completely rusted away. I thought it was supposed to be ss. The galvanized upper section that fell is still in great shape.

Now to try and find a 2' section of insulated pipe that has the same stack diameter and same outer diameter so it fits through all the holes. I think they stopped making this - guess now I know why!!

My guess the SS pipe rusted was galvanic corrosion, google it

[BCPP]

Possible I suppose, had not considered that. But it was very uniform corrosion. The parts of the flange left, that had not been torn away by the top section screws, I could easily tear off with my fingers.

[maple flats]

What name is on it? unfortunately different brands don't inter change.
What my evaporator has is a single wall SS 12" stack from the SS base stack thru the roof and to the SS flpi top cap. I then made a section of insulated stack that is supported from the trusses that is 1" ceramic blanket insulation rated for 2100F, then I made a clamp on cover, out of galvanized 24 ga., bent the last 3/4" on each end and bolted it to form a complete circle. The bottom is cut 1" every inch around and bent inward to support the insulation. That cover is cut to match the under side of the roof steel and is tight against it. We must get fire dept inspection for any solid fueled device. Mine passed with flying colors and has been like that for several years. Before that I had a galv stack and made it into triple wall with spacers out of sheet metel bent into a Z shape. They were placed 4 around each layer and held a 1.5" space. They were made using 28 ga sheet metal, no insulation. That didn't look as neat but it also passed fire dept inspection. The looks was because to get a 15" diameter, I opened a 7" and an 8" ready to assemble pipe and snapped it into a 15", The outer layer was done the same, connecting 2 at 9" each to make an 18". They worked but were certainly not round.