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Monday, January 16, 2012

Butane Adapter WARNING

A butane adapter can be a nice thing to have.  I mean, if the weather's warm, why not just use cheap 100% butane canisters with your backpacking stove?  Cheap 227g butane canisters are available for about $1.25 at the cheaper stores whereas backpacking canisters usually sell for about $6.00 for the same amount of fuel.

There is however a butane adapter being sold that can be really DANGEROUS if you don't know what you're doing.

I've seen a few different colors, but most are black and look something like the below.
A butane adapter -- POTENTIALLY DANGEROUS
These adapters allow one to mate a cheap 100% butane canister with a standard threaded backpacking stove.
A cheap 100% butane canister of the type frequently used in restaurants for table side cooking
These butane adapters have a protruding "lug" on them.  THIS LUG IS IMPORTANT.
The lug on this adapter can be seen near the top of the photo.
The lug must remain pointed up whenever a stove is in operation.  Let me explain why and what happens if you mess this up.  The lug fits into a gap on the collar of the butane canister.
A butane canister (left) has a notch that the lug on the adapter (right) fits into
OK, let's hook the adapter to a backpacking stove's fuel hose.  ALWAYS hook up the stove first and the canister last.  There is no valve inside this adapter.  If you hook up the canister first, butane will spew out in an uncontrolled fashion.
A butane adapter attached to the valve on the end of a backpacking stove's fuel hose.
OK, we're all set, let's hook up the canister.
A butane canister mated to a backpacking stove via a butane adapter.
Note how the "lug" separates.  Part of the lug stays in the notch in the collar and part of the lug rotates to the right.  The part of the lug that stays in the canister needs to stay pointing straight up.

OK, we're all hooked up.  Let's fire it up.
A backpacking stove running off of a cheap 100% butane canister
Well, heck, looks fine to me.  So what's the problem?

I'll tell you what the problem is.  Remember in the photo above how I said that the lug needs to point at the sky?  What prevents the canister from rolling over?  NOTHING.  That's right.  There is absolutely nothing that prevents that canister from rolling or turning in some fashion.  And what happens if the canister rolls?
The stove flares up uncontrollably if the canister rolls over.
WHOOMPH!  If the canister rotates or rolls for any reason, almost instantly, the nice well behaved flames we saw in the previous photo can turn into the big yellow flames seen immediately above.  Note that the above photo was taken after the flames had settled down a bit.  I knew it would flare, and I was expecting it (I turned the canister deliberately).  Still, I was surprised at just how BIG the flare was.  The flare extended out at least a foot (~30cm), maybe more on the downwind side.  Uh, hope you weren't leaning over the stove to check the stew when the canister rolled.

Why does it flare?  There's a fixed position plastic tube inside the canister.  The plastic tube points up, up toward that notch you saw in the collar of the canister.  The plastic tube is designed to suck vapor -- which it does quite well so long as the canister is oriented with the notch up.  But recall that the majority of the fuel in a canister is in liquid form.  If the canister rolls a bit, then suddenly the tube is plunged below the surface of the liquid, and liquid fuel is squirted into the burner.  Whoomph!  A flare erupts.
A butane canister valve assembly.  The notch should always face UP.
I believe that the adapter shown is fundamentally unsafe if the canister is laid on its side -- which is the most desirable way to use a tall canister.  A harsh judgement, I realize, but there just is nothing to prevent that canister from rotating and flaring.

What's that?  If your stove has a pre-heat loop, wouldn't it be OK?  Well, yes, but you'd better make sure the canister doesn't roll until the stove is warmed up.  Yes, you could use this type of canister in side laying mode on a stove with a pre heat mechanism -- if you were careful.  So be careful.

I believe this type of adapter is safe if the canister is standing up.  I strongly recommend that you use something like a Brunton Can Stand like the one shown in the photo below to stabilize the canister.  If the canister were to fall over, a dangerous, uncontrolled flare would result.
A butane canister, upright, stabilized by a Brunton Can Stand
That's my warning.  This adapter is generally not recommended.

Thank you for joining me on another Adventure in Stoving.

HJ

SUMMARY
1.  The adapter is well made, but it's too easy for the canister to roll accidentally which could cause a serious flare.  Therefore, this adapter is generally not recommended.
2.  Never use this adapter with a side laying canister on a stove without a preheat mechanism (generator).
3.  If you are cautious, you could use this adapter on a stove with a preheat mechanism (generator), but be aware that it's very easy for this type of canister to go into liquid feed mode accidentally which could trigger a flare if your stove hasn't warmed up yet.
4.  This adapter is safe if the canister is used in the fully upright position, so long as the canister doesn't fall over.  I strongly recommend that you use some means to prevent the canister from tipping over.

12 comments:

  1. Nice to know. Does it say anything on the can about the notch being at the top? Not that anyone reads the safety stuff on the can.

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  2. Hi, Bill,

    Not really. There's nothing on one brand. The other brand I have has a diagram but doesn't really explain it or say why.

    HJ

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  3. Hi Jim, Great blog entry!

    I've had my eye on the Fire Maple FMS-100t stove, and I notice in Asian videos like this one, the butane adapter is commonly used:
    http://www.youtube.com/watch?v=zQqsaDAIev0
    Here's another one in Thai, but I still enjoyed watching the Thai outdoor cooking demonstration with the Fire Maple Stove and the butane adapter:
    http://www.youtube.com/watch?v=qAUjWmVHQ-g

    I can get the plain butane cans locally for a little over a buck each, so I'm going to take your advice and use the butane canister upright with the can stand.

    Any thoughts on the Fire Maple FMS-100t?

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  4. Hi, Art,

    The FMS-100t of course is not the stove shown in those two videos. The stove in the videos looks like a copy of the Snow Peak Crab-Li.

    The FMS-100t does not have a pre-heat loop which makes it a little less safe if the butane can tips over or otherwise feeds liquid butane for any reason. However, if you're using a canister stand that holds the can upright, then there should be no problem in using the FMS-100t.

    HJ

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  5. Wow,I'd never heard of the Snow Peak Crab-Li. The Fire Maple FMS-100t seems like it might be a clone. The Fire Maple website says it has "two-channel preheat," not sure what that means, but the fuel tube seems to follow the burner the long way around rather than the vertical loop the Kovea Spider uses.
    http://www.fire-maple.com/products_del.html?news_id=42&c_id=5&cate_id=8

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  6. Art,

    First, my apologies, I was mixing up the FMS-118t and the FMS-100t. Thank you for that link. I should know better than to rely on my memory! The 100t *DOES* have a pre-heat loop which will make it safer.

    As for the clone issue, here is the Snow Peak stove:
    http://www.snowpeak.co.jp/catalog/products/detail/509

    Here is the Fire Maple stove:
    http://www.fire-maple.com/products_del.html?news_id=42&c_id=5&cate_id=8

    The look visually very similar.

    I haven't used the FMS-100t, but I would think it would work well. It looks very stable. I think it's a good design for use with the butane adapter.

    Let me know how it goes,

    HJ

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  7. Thanks Jim. Looking at the snow peak site, the Fire Maple has the knob on the canister attachment and lacks snow peak's cool inverted canister stand. In the Fire Maple's favor, it's titanium and quite a bit lighter than the snow peak. It does seem to have the same type of fuel tube design that goes around nearly the entire burner head. I'm hopeful that this will make a good inverted cartridge stove. I ordered it today, I'll let you know what I think when I've had a chance to use it. Thanks for the great, and I mean GREAT, blog!

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    Replies
    1. Hi, Art,

      Did you ever get a chance to try out that Fire Maple stove?

      HJ

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  8. I'm curious if the butane adapter would work on my MSR XGK? It's a bit harder to source white gas locally and butane canisters are more available? I can probably get an adapter for about $10 here. Thanks!

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    1. No, this type of butane adapter would not work on an XGK. You can use kerosene with an XGK. Kerosene is frequently easier to find than white gasoline, depending on where you live or plan to travel.

      HJ

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  9. Even after reading this section several times, I still decided to buy one of these adapters (Fire-Maple FMS-701) to try out.
    Taking your safety warning into consideration, the adapter did work well with a Fire-Maple stove (FMS-105, no preheat loop) with the canister placed vertically and on a Primus can stand.
    The fuel line ended up being almost vertical and was only about 2 inches away from the kettle on the stove...I wasn't comfortable with that although the fuel line never got hot.
    I also tested the adapter with an Optimus Vega and it leaked very badly until I tightened the connector almost to the stripping the threads....not good.
    A bit of detective work showed that the connector on Fire-Maple stove has one less set of threads than the Optimus stove.
    In the end I located a local store that sells 450g (16 oz) Isobutane/Propane canisters for only $1.55 more than what a pair of the 100% butane canisters cost....definitely not worth cheaping out for less than $2.

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  10. Hi Jim,

    First, I really enjoyed your latest post of your article for Gossamer gear. Glad to see you are still blogging. This is probably my favorite blog of all time, and I return here frequently to educate myself.

    I put up a video of my experience using this adapter with the Kovea Spider and Fire Maple FMS-100T stoves this past weekend. Both stoves (with pre heat tubes) seemed to handle the standard butane canisters in any position at 59 degrees without much trouble. I didn't think to bring a windscreen, so the built in windscreen of the Fire Maple favored it for this hike.

    http://youtu.be/u52azjti4L4

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