This post describes various cheap options to make replacement flame guides that are a crucial working part of a tent heating dome stove.
Introduction
The flame guide in the KISS Stove is a thin stainless steel foil wall, between the fire dome floor and ceiling. It cuts across the fire dome to separates the wood pyrolysis and charcoal combustion zone from the smaller zone that forms an exhaust channel where the wood gas combustion is largely completed.
The guide forms a labyrinth within the fire dome. It forces the exhaust gas and flame to take a long path toward the flue pipe via a hole that is formed at one end of the wall. The gases and flames turn sharply and turbulently through the hole in the guide to head back toward the exit port to which the flue pipe is connected. Creating turbulence is deliberate as it improves the combustion of wood gas by better mixing of oxygen with it and better heat exchange to the stove surface.
The flame guide
The flame guide is made of 0.1mm thick stainless steel foil. It functions in the hottest part of the stove within the fire dome. It experiences the harshest heat/flame environment, without anyway of being able to ‘sink heat’ into a cooler zone.
“It’s like being sandwiched between Hell and Hades. There’s glowing turbocharged charcoal (1,000C) and flames (700C+) on the face and flames on the backside, with nowhere to hide.”
It just needs to be replaced periodically, but it will give many hours of service and comfort before replacement will be required. The decay is progressive and gives plenty of warning before it becomes unserviceable.
The design. The guide is designed to be ultralight, cheap and simple to be replaceable with scrap if spare parts are not available (As all good designs should.). “Even ‘free’ coffee can or olive oil tin-plate that is about 0.4mm thick will do the trick.” Several guides could be made at one time to allow for the more rapid decay of this mild steel.
The fitting. In previous stoves, the guide has been a fixture that has been welded in place and once burnt out it makes the whole stove unserviceable. The new dome stove guide had only a tiny folded tab as its tenuous connection to the stove on the fire dome flange. The tab can be seen at the front of the above photo. It had only a single tab and worked well enough. Now I use two tabs (as shown in the photo below), one on each end and this makes it more secure. Luckily, the tabs are in a low heat zone of the stove and they are not damaged by stove heat.
Removability. The tab fitting means that the guide can easily be slipped on and off to replace it and to make a more efficient space in the fire dome for packing all the stove components within it.
[Add the video of stove assembly, including the clip-on of the flame guide and insertion of fuel/burner tube and flue guard tube.]
Flame guide material. The flame guide could also be made of 10 times thicker stainless steel sheet and this should last a very long time, but it will be 10 times heavier.
Possibly a good compromise would be to make the guide out of 0.4mm thick stainless steel sheet. “This is abundantly available as a gift in ‘curb-side chuck-outs’ of kitchenware from our wasteful society.” It is easy to cut and form and should last four times longer than the thin foil. “I have not yet tried this heavier material as I am trying to ‘clock-up’ hours of burn time with the thin foil guides to find their limitations.”
Conclusion
When flame guide replacement is needed, it will come gradually. There should be workable replacement guides for all budgets and levels of tinkering. “It is all a compromise between cost, weight and durability.”
Related posts in this series are:
Tim
