Soto WindMaster OD-1RX 'micro regulator' canister gas stove

Discussion in 'Japan' started by presscall, Dec 11, 2015.

  1. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

    Offline
    Joined:
    Aug 25, 2009
    Messages:
    9,374
    Here's the stove with the 4-leg removable pot rest fitted. A smaller and lighter 3-leg pot rest can be substituted to suit smaller pots

    image.jpg

    image.jpg

    image.jpg


    Given it's mounted on top of a gas canister it has a robust base fitting bracing the stove against the rim of the canister flange with a second, outer, O-ring to provide a secondary gas-tight seal against the inside of the flange

    image.jpg

    image.jpg


    The 4-leg pot rest clips onto the burner head with a sprung-loaded scissor action

    image.jpg image.jpg image.jpg


    The 3-leg pot rest folds up very compactly and also clips onto the burner head, relying on the springiness of the thin stainless steel to clip it securely into place.

    image.jpg image.jpg image.jpg image.jpg


    So far so good, but the genius of this stove is the outstanding effectiveness of the 'micro regulator'. Here's the explanation of the principle from the instruction leaflet.

    image.jpg


    I've made extensive use of this Soto stove that also has the device fitted and have proven to my own satisfaction that it works very well indeed.

    Those of us who use canister gas stoves as well as the liquid fuelled classics are only too familiar with the effect of evaporative cooling of the gas in the canister after a minute or two of use. Noticeable on anything but a hot day and a real problem when the ambient temperature is freezing, the power of the stove drops as evaporation of the liquefied gas in the canister lowers the temperature of the remaining fuel and reduces the vapour pressure of the evaporated gas entering the burner.

    The Soto works by having a 'floating' micro-spring loaded valve (the heart of the regulator) in conjuction with a jet nipple with a much larger jet orifice than in an orthodox canister gas stove. Soto jet on the left, a Primus stove jet on the right ...

    image.jpg


    ... when the vapour pressure of the gas has reduced due to evaporative cooling, made worse by cold outdoor temperature, the Soto sprung-loaded bobbin valve in the regulator opens more than when the vapour pressure is higher on a hot day. Whereas a conventional stove jet would throttle the gas flow the larger bore of the Soto jet doesn't to anywhere near the same extent and in spite of the reduced pressure of the gas the flame intensity and heat output is maintained.

    A bonus is that the simmering capability is phenomenal and because of the regulator, whatever flame intensity is set it stays at that level and there's no fluctuation in use, right down to when there's just a whiff of gas remaining in the canister.

    I'm convinced that it out-performs other canister gas stoves in terms of that rather important feature but how's it compare in other respects?

    It's comparable in weight terms with all but the Optimus Crux Lite (which is a little bit lighter) in this group. Bulk and packability is about the same, but taller than the other three when mounted on the canister.

    image.jpg

    image.jpg

    image.jpg


    The Crux does that 'stow in the concave base of the canister trick of course.

    image.jpg


    The simmering control of the Soto is obviously better and more stable.

    image.jpg


    Maximum power is comparable with the rest - but stays at that level.

    image.jpg


    The 'WindMaster' claim is attributable to the shrouding of the burner and the concave burner rose, which together with the vertical column flame pattern (as the Primus has) certainly offers a fair measure of wind resistance, particularly when a pot is on board.

    image.jpg

    image.jpg


    In that respect, it's an improvement on my other Soto with it's convex (and un-shrouded) burner rose

    image.jpg

    image.jpg

    image.jpg


    Both are powerful ...

    image.jpg


    ... and simmer well

    image.jpg

    John
     
  2. Normo

    Normo Subscriber

    Offline
    Joined:
    Feb 25, 2013
    Messages:
    579
    Thanks for the review John. I am considering getting one of these, so your review came at a good time.

    Any comments on the stability of the pot rests with larger / heavier pots?

    And issues of reflected heat with larger pots, given the micro regulator design.

    I already have one of the folding Crux stoves, some (including mine) have a slight wobble at the joint. It puts me off a little.

    Thanks

    Norm
     
  3. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

    Offline
    Joined:
    Aug 25, 2009
    Messages:
    9,374
    @Normo
    My Crux has that wobble too, Norm, and since the Crux Lite is as powerful and has the same pot rest spread I'd judge it to be the better stove.

    Head and not heart judgment speaking there though, since the Crux's folding trick always entertains (hey, we've an enthusiasm for these things and it's not always just the practicalities that tick the box, right?)

    The Soto's rock solid with either pot rest version. No worries on the stability front and you'll notice the greater height of burner above fuel canister mount over the other stoves? I reckon the longer riser tube is to ensure there's effective fuel/air mixing with the lower gas velocities when the temperature drops.

    Benefit of that as a side effect is the greater thermal separation of pot base from stove regulator. It's not so much to make the lot too tall to be unstable however, though if I were using a larger pot I'd either connect the stove to a bigger capacity, larger diameter fuel canister or use one of these ...

    image.jpg

    image.jpg


    The 4-leg pot rest is an accessory and doesn't come with the stove and 3-legger. Around 14 GBP.

    I was lucky and got stove and the 4-leg pot rest, unused but no box for £30 'buy-it-now' off ebay. Even at full retail price I believe it's a cracking stove, best of the bunch.

    I'd best add, I've no commercial connection with Soto whatsoever!

    John
     
  4. geneislucky

    Offline
    Joined:
    Jan 4, 2013
    Messages:
    309
    Thanks John. I have wondered about the effectiveness of these kinds of valves. Do you find the concentrated upthrust of the burner head causes food burning?

    I find for my actual use I don't need specialty designs. My users are Snowpeak Litemax and MSR Windpro.
     
  5. geneislucky

    Offline
    Joined:
    Jan 4, 2013
    Messages:
    309
    I use the bottom canister brace for my top mounted Snowpeak. Helps greatly and quite worthwhile for me.
     
  6. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

    Offline
    Joined:
    Aug 25, 2009
    Messages:
    9,374
    I've used that Primus a lot and haven't found it so, throttled down, and the Soto has a broader burner head which spreads the heat even better than the Primus. It's got that amazing controllability too, right down to the lowest simmer of anything I've used (other Soto I have apart) and the stability of the regulated flame means there's no risk of it puttering out, or overcompensating by turning up the gas too far.

    John
     
  7. Normo

    Normo Subscriber

    Offline
    Joined:
    Feb 25, 2013
    Messages:
    579
    @presscall

    Thanks for the reply John. You've given me an excuse to get one!

    Down here, they come standard with the 3 & 4 leg pot supports for AU$109 full retail. I'll wait until a sale is on and get one then.

    I already have a couple of cylinder base leg extensions.

    Regards
    Norm
     
  8. tekkster

    Offline
    Joined:
    Dec 5, 2014
    Messages:
    131
    Wow! That was an awesome review. Great burn photos and very cool field strip photos.

    Thanks!
     
  9. hikin_jim

    Offline
    Joined:
    Apr 17, 2009
    Messages:
    4,519
    @presscall,

    A very nice review indeed. And, of the upright canister gas stoves I'm aware of on the market today, I think the WindMaster is the best of the lot in terms of build quality, performance in wind, and ignition reliability. It has an impressively low simmer as well. I've found the little "clip" style pot support to provide surprisingly good pot stability, and the 4Flex even more so. I used a 2.6 L pot on my John Muir Trail trip this past summer with a WindMaster equipped with the 4Flex pot support. No stability issues at all, even when laden with more than 2 liters of water, which is pretty good for a little gassie.

    Your observations about the jet size are spot on. Coincidentally, I did a write up (prompted by some questions from a mountaineering friend) of why regulator valved stoves are better (assuming they're well designed) performers in cold weather. If anyone were interested: Gas Stoves in Cold Weather – Regulator Valves and Inverted Canisters

    HJ
     
  10. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

    Offline
    Joined:
    Aug 25, 2009
    Messages:
    9,374
    I greatly enjoyed reading that piece and seeing the video of the Windmaster and Jetboil @hikin_jim.

    . Succinctly put to draw the reader in, coupled with well-presented evidence to make the case. Great stuff.

    I'm still hugely impressed with the Hank Roberts as an early 'technology' solution to deal with the problem of cold ambient temperature and/or evaporative cooling of the gas. It came through a 'freezer test' with no difficulty.

    IMG_3755.JPG

    John
     
  11. hikin_jim

    Offline
    Joined:
    Apr 17, 2009
    Messages:
    4,519
    Well, thank you. Pressure regulators are interesting animals -- and certainly of benefit. But there is a point where the combination of a larger jet and regulator just can't compensate for lack of pressure. There are so many myths about what a pressure regulator can do. I hope that video dispels some of them.

    Your photo of the side by side jets where one can clearly see the difference in apertures is just absolutely brilliant. Fantastic. Do you have any idea what size the Soto is? The Primus appears to be 0.32 mm, yes?

    Thank you, John. I am by no means a ground breaker or pioneer. I consider myself something of an aggregator or perhaps synthesizer. I read a lot of things and such and then, God willing, bring them together and (even bigger stretch) make them plain. On a good day. Sometimes I go back and read what I have written a year later and just cringe. :lol::oops:

    Yes, isn't that amazing? For all the sophistication of something like the WindMaster, the Hank Roberts was able to match it 30 or 40 years ago -- with a lesser fuel (in terms of cold wx performance). Astounding, really.

    HJ
     
  12. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

    Offline
    Joined:
    Aug 25, 2009
    Messages:
    9,374
    @hikin_jim
    Glad to oblige.

    Some dismantling was necessary to get access to the jets.

    Left to right: Soto 310; Soto Windmaster; Primus Express

    IMG_3757.JPG

    IMG_3758.JPG


    I used a 0.4mm micro-drill shank to size up the two Sotos (both had that diameter of jet orifice).

    A 0.32mm jet pricker wouldn't fit the Primus jet, but a 0.23mm pricker did.

    Doing the maths to arrive at jet orifice surface areas, that of the Primus is 0.0416 sq.mm. For both Sotos the figure is 0.1257 sq.mm. or a little over four times the surface area.

    It's not hard to visualise the greater throttling effect of a conventional jet/valve arrangement compared to the Soto type jet/valve for a given gas vapour pressure.

    Conversely, it's easy to see how the combination of the Soto's sprung-loaded regulator valve and (comparatively) non-restricting jet comes into its own when gas vapour pressure is low when low ambient temperature and/or evaporative cooling pertain.

    That said, Jim, you were of course absolutely right when you said
    It is though at a point beyond which the usual jet/valve equipped stove will have petered out.

    An experiment ...

    Having reassembled those stoves I set a litre-and-a-half of water to boil on the Primus out on the patio in near-freezing outdoor conditions and evaporative cooling of the gas reduced output to the point where it just managed to achieve boiling at the six minute mark, at which point the flame had reduced to the equivalent of a simmer.

    I then connected the Soto Windmaster to the same gas cart without warming it up and set a fresh 1 1/2 litres to boil. The Soto achieved a vigorous boil in four minutes and had capacity (though reduced in output, but more than a simmer) for another pot, should I have wanted one.

    Good to talk with you as always Jim.

    John
     
    Last edited: Jan 3, 2017
  13. hikin_jim

    Offline
    Joined:
    Apr 17, 2009
    Messages:
    4,519
    The perfect experiment, @presscall.

    If the WindMaster can take an already chilled canister and operate well on it in cold conditions, then what more proof is needed? That's rock solid proof if you ask me -- not that there was any doubt. The pressure regulator makes safe in hot weather a (much) larger jet size that would be, er, "ill advised" :shock: on a needle valved stove. The size difference is apparent even to the naked eye, but thank you so much for taking actual measurements.

    Out of curiosity, how accurate is the 0.23 mm measurement? Does the pricker just fit or is it a bit loose? I don't suppose it makes a critical difference; the Primus jet is obviously smaller than the Soto jet. Just me being a perfectionist or something. I like to know. :lol:

    But four times the cross sectional area! That's quite a lot. No wonder the Soto can pick up where the Crux left off, operating well on an already chilled canister.

    And were you using Jetboil brand canister gas? It should have good pressure down to about 0 C to -2 C (canister temperature) even when nearing empty since it contains no n-butane but instead contains only propane and isobutane (well, for practical purposes. Of course there's always some n-butane present, isomers being what they are). Once it dips below freezing though, it will inevitably start losing pressure. As it approaches -7C, assuming that it's mostly isobutane left, the Crux will struggle, but the WindMaster will continue on well. Once it approaches -10C or so, both will struggle. Something like that. The closer one gets to the boiling point of the fuel (approximately -12 C for isobutane), the lower the pressure, and all stoves will struggle when the pressure gets low enough.

    Nice to tie everything together with a practical example like this. :thumbup::thumbup:

    HJ
     
  14. hikin_jim

    Offline
    Joined:
    Apr 17, 2009
    Messages:
    4,519
    Oh, and by the way, that Soto 310 is a very interesting stove. I've seen it on the Soto website, but it's not available here. Kind of odd though having a regulator valve on a stove designed for n-butane! They'd do a lot better by switching to a better (in terms of cold weather performance) fuel.

    HJ
     
  15. ArchMc

    ArchMc Subscriber

    Offline
    Joined:
    Jul 25, 2004
    Messages:
    2,879
    Location:
    Mojave Desert, California
    Really interesting post.

    I don't often have a chance to catch Maestro @presscall out, but...
    I think that should be "a little over three times the surface area".:-k

    ....Arch
     
  16. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

    Offline
    Joined:
    Aug 25, 2009
    Messages:
    9,374
    @ArchMc @hikin_jim
    Whoops, Arch, three times the area it is! I must have been jaded after wrestling with Pi and calculation.
    I resorted to a 0.23mm pricker simply because I didn't have a micro drill small enough to fit the Primus jet. Turns out it was a precise fit, not loose, so I'm happy with the accuracy of the measurement and I (just now) ran a micrometer over the actual pricker in case it was off specification, which it wasn't. A modern gassie Primus with a kero stove era jet size? I have this fond notion that Primus have stacks of 0.23mm micro drills from their No.96 vapouriser manufacturing days ... more probably it's determined by what provides the right fuel/air ratio.

    In respect of the gas I used in the test, it was butane. It had been a proprietory isobutane-filled cart originally but I'm in the habit (whisper away from the 'Frankies, Mods and Hybrids' forum) of refilling such from cheap bayonet cart sources, which of late have been unblended butane.

    Yes indeed regarding your comments on the soto 310 and its gas cart fuelling HJ. It's still a very effective stove nevertheless and some of the bayonet cart supplies I've had have been isobutane, which unleashes the potential you speak of.

    John
     
    Last edited: Jan 4, 2017
  17. hikin_jim

    Offline
    Joined:
    Apr 17, 2009
    Messages:
    4,519
    Oh, that's right. I have heard that some of the cylindrical bayonet type canisters in the UK are isobutane. Here in the US, they're all 100% n-butane.

    John's photos of the jet sizes are the perfect illustration of what I was writing about in Gas Stoves in Cold Weather – Regulator Valves and Inverted Canisters

    I've now revised my post to include one of John's photos (with permission). Again, it's just the right illustration.

    On a mathematical note, I just realized that I wrote "double" the size (referring to the relative jet sizes). Oops. How many stovies does it take to solve a simple math problem? :lol:

    HJ
     
  18. ArchMc

    ArchMc Subscriber

    Offline
    Joined:
    Jul 25, 2004
    Messages:
    2,879
    Location:
    Mojave Desert, California
    I'm actually a little embarrassed for pointing out the discrepancy, when it was obvious from context what was going on. I was reading rapidly, saw "0.04..." and "0.12...", and by the time I got to "four times", I had already calculated "about three times", and somehow felt compelled to report it. You can retire from a job, but sometimes you can't leave it behind...

    ....Arch
     
  19. hikin_jim

    Offline
    Joined:
    Apr 17, 2009
    Messages:
    4,519
    Ah, but best to have things straight, Arch. :)

    HJ
     
  20. presscall

    presscall United Kingdom SotM Winner SotY Winner Subscriber

    Offline
    Joined:
    Aug 25, 2009
    Messages:
    9,374
    ... some years have passed! The Windmaster is still going strong and a Soto Amicus came my way. Comparison review with the Windmaster is HERE.

    John