5 Responses

1. Hi

   I am just wondering about the status/availability/price of the LOFI 2.0 stove and I also have a couple of more specific questions.

   1) I have both bought and made many wood gasifier stoves over the years from smaller than the LOFI up to big cans that burn for 90 minutes on wood pellets. I’m a fan of the idea and have experimented a lot with airflow – in particular the balance between primary and secondary air – but never forced induction. I have found that even when you burn very lean and force mixing so that you manage to get a bluer/hotter flame you always get some soot on the cookware which can then turn dark and sticky soon enough. I am wondering if the forced induction burns more of the heavy tars and so avoids this?

   2) All the stoves I have used have been in stainless steel, and eventually the inner burn chamber rots from a combination of the high burn temperatures and the acidic residue left by burning wood. Titanium should be better because of the higher melting point and corrosion resistance respectively. Have you done longevity testing on the burn chamber in your design? It’s a consideration for a stove this expensive.

   Many thanks

   Michael

   Reply

   1. Hi Michael,

      Thanks for the thoughtful message. Sounds like you’ve gone properly deep with wood gas stoves over the years, so you’ll know exactly where the tricky bits are.

      LOFI 2.0 isn’t available just yet, but it should be online at the end of July, when the next batch is made up.

      On soot – forced air helps a lot. It gives a much more consistent burn, especially once the stove is hot, and does a good job of burning off more of the smoke and heavier gases than a natural-draft stove. In my experience there’s noticeably less soot on cookware, but you still get some creosote condensing on the cooler surface of the pot. Over time this tends to form a hard, shiny black coating rather than the softer soot you often see with less efficient burns. It’s still a wood-burning stove after all, so I wouldn’t call it completely clean. Fuel type, moisture content, and how hard you run it all play a part. When the coating builds up, I usually remove it with a bit of oven cleaner spray and it comes off without too much trouble.

      On longevity – yes, that’s been a big part of the testing. The burn chamber is titanium, partly for weight, but also because it deals with heat and corrosion far better than the stainless chambers I’ve used and tested in the past. I’ve been running repeated burn cycles to look for distortion, thinning, cracking, and general wear. So far it’s holding up well.

      Totally understand the concern at this price point. It’s not meant to be a disposable bit of kit.

      Thanks again,
      Jonny

      Reply

2. Thanks for the reponse Jonny I will keep an eye on developments for LOFI 2.0.

   Re: cleaning the soot off pots, I have found that pound shop nail varnish remover (including the one without acetone) works really well.

   Re: longevity I forgot to mention the issue that many modern small fans use Neodymium-Iron-Boron (NIB) magnets for compactness and light weight. NIB is almost magical in terms of generating high flux densities in tiny packages (I used to work in electroacoustic design) but it does have an Achilles heel – a lower Curie temperature and a surprisingly low maximum operating temperature as low as 80-100C, though higher-temperature versions are available. This means that it can demagnetise if placed too close to a heat source and the burn chamber must be at several hundred C. Have you experienced any such problems? Perhaps you are sourcing fans with ferrite magnets which are far less susceptible.

   M

   Reply

   1. Hi Michael,
      Thanks for that tip – I’ll have to give the nail varnish remover a try. I’ve mostly used oven cleaner over the years, but it’s always good to hear what others have found works well.

      That’s a good point about the fan magnets too. The original LOFI 1.0 I think used a fan with neodymium magnetic material, whereas the newer 2.0 uses a ferromagnetic material that’s able to tolerate around 20% higher temperatures. The fan’s positioned for the airflow through the stove which helps keep temperatures around the motor and electronics much lower than those in the combustion zone.
      It’s something I’ve paid close attention to during testing. The stove has been through a lot of long-duration burns and repeated high-power cycles, and I haven’t seen any signs of fan degradation or loss of performance. As you’ll know, though, heat has a habit of exposing weaknesses over time, so it’s one of the areas I’ve continued to monitor throughout development.
      Thanks again for the questions – it’s always interesting chatting with someone who’s clearly spent a lot of time experimenting with these stoves.

      All the best,
      Jonny

      Reply

3. So I have this week been conducting experiments with my first small forced-induction stove and when you get the primary-to-secondary ratio right it does indeed produce almost no soot on the base of the vessel even with non-ideal fuel. Very promising. It has reinforced the truth of what the serious TLUD designers have been saying for some time i.e. the importance of “the 3 T’s” for clean secondary combustion (Time, Temperature, Turbulence).

   M

   Reply

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