All my Central and Wood master guys insist that there wood needs to be seasoned in order for it to burn. They do not have forced air induction like it std with a heatmor. They also dont have A grate that holds the wood up for the air to blow under it to burn the wood and let the ashes fall into the ash auger trough std. if you add up all the features that are std on a heatmor including the fire brick, and the stainless stell that has nickel in it so it doesnt crack like the cheap stainless you cant beat it. I will also tell you that the people that i sell wood to that have a heatmor Owb use less wood. That is what i see on a consitant basis to the people i sell wood to. I will tell you this also, any OWB is a good investment no matter wich one it is it is still cheaper than filling that pig all the time. One more thing dont let the fiberglass insulation scare you either, i have snow on the roof of mine when it is running, and if there ever is a problem i would much rather deal with removing that fiberglass then that spray on crap, and with the fiberglass the metal can breath and not trap the moisture in between the insulation causing rot. again just my .02c
The questions that have been brought up have made me think of numerious questions to be asked. BTW- This is just me thinking out loud.
With dealing with insulation, rather than fiberglass, why not go with something like "Ruxul" insulation. Water does not go into the insulation, but instead, beads off of the insulation. I know that this now asks that the metal of the boiler be prepped with a coating like "paint" so the water beads off of it.
Yes, spray foam seals the outer layer of the boiler, but water is a very intrusive commodity that you don't know what it is going to do. One of the biggest problems with spray foam, ofter the fact of having a leak, is dealing with a leak. How far have you got to go to find the source of the leak?
Now once you have found the leak, what other hydrocarbons have been introduced to the leak area due to the source of sealing properties(paint, foam, water, additives to the water, metal compound reaction)?
I don't mean to go so in depth, but as someone who wants to build his own outdoor wood boiler, these questions and probably answers have to be answered. Yes I know that I will have "company" responses, but if truly want a true lifetime warranty, BUILD IT YOURSELF AND FIX IT YOURSELF!
PS: This is not in any way meant to get anyones dander up, just something that has to be thought of in the variances of wood boilers.