Firebox Corrosion Analysis with Pictures

[salecker]

So I happened to be in my boiler building today with some extra time.
Took a picture of the inside of the burning chamber
And one of my hand after rubbing the roof of the chamber
Then I tried to clean around one of the stays. No sign of any moisture. It was hard caked on creosote
I chipped it off around the stay and cleaned the weld as good as I could.
I feel that by the appearance of the weld and surrounding metal that my boiler is experiencing zero corrosion on the fire box side of the metal
I don’t know anyone with an ultrasonic measuring device to prove me wrong.
It’s been a couple weeks since my last fire and the boiler temp is below 70F as that is as low as the gauge goes and the needle is sitting on the peg

 

[cumminstinkerer]

I don't really know guys, maybe its just chitty places in the steel, a lot, like 95% of the hotroll we get is recycle anymore so you never know. the one I fixed had about an 18 inch square area at the back that was ate up, not totally but I went out that far to be sure and get into good metal, otherwise I could not find any thin areas, when I had the chunk out I used the old finger caliper method and could find no thin areas, not super scientific but I do auto body work and can feel fairly accurate

 

[JMihevic]

The inside of my Tarm MB 55 always looks like that -- hard and flaked creosote. It has for 46 years. I installed it in 1980 and have heated my home every winter with wood. I have never had any corrosion of the steel. Creosote is very corrosive if there is moisture/condensation. Every year, after I am done burning for the season, I put a10"X12" aluminum plate inside the MB 55. I have a 60 Watt surface mount resistor fastened to the plate. The plate/resistor will increase the boiler water temp 5 degrees above the ambient temperature. This ensures the steel boiler walls will always be above the dewpoint and the steel walls will never have any moisture on them.

 

[salecker]

It must be out dry climate up here
The first few years of having my system going i would check to see if there were any signs of moisture, as i would always read about things people did to their units over the off season
It's always been the same caked on hard dry creosote.
I actually am very happy with my Econoburn being basically bulletproof, it can use a few improvements.
Had i not found Hearth, and gone with my original plans i would have had a subpar system with crap lines that would have made winters unbearable.
Thank You everyone who posts their experiences, winter heating for me is systematically boring.