Canister Refiller -- WARNING

I've been seeing a particular canister refilling device on eBay lately as a "MacCoupler Liquefied Gas Refill Adaptor Gas Charging Valve Inflatable converter" [sic].    This particular device is just downright dangerous and in general should be avoided.  I'll explain why I say "in general" in a minute.

A very dangerous canister refiller.  ** AVOID! **

OK, so what's wrong with this refiller?  Well, in case you don't recognize the fittings, this refiller will refill backpacking type gas canisters from a "bulk" propane tank.

A "bulk" type 100% propane tank

Hey, now doesn't that sound like a great idea?  Hey!  I can take cheap gas out of my bulk propane tank (like for a BBQ) and refill my expensive backpacking canister.  Pennies on the dollar!  Sweet!  What could possibly go wrong?

What could go wrong?  A whole lot, and it could be bad, very bad.  First, backpacking canisters do NOT contain 100% propane.   Standard backpacking type canisters in the US are rated at not more than 20% propane (mixed with 80% isobutane) or 30% propane (mixed with 70% butane).  Propane is a very high pressure gas.  Put 100% propane in a canister rated for only 20 to 30 percent propane and what do you get?  Quite possibly a very nasty explosion.

Oh!  I know!  If my canister is only rated for 20 to 30% propane, I'll just fill it up to 20% of capacity and leave the rest empty!  Duh!  Problem solved.

Uh, not exactly.  When combined with butane or isobutane, propane actually forms a blend.  The resultant blend has a lower vapor pressure than 100% propane.  Odd as it sounds, you'll actually have less vapor pressure in a canister with 20% propane and 80% isobutane than a canister 20% full with propane alone.  Besides, what good is a canister you can only fill to 20% of capacity anyway?

Basically, you should never fill a backpacking type canister with 100% propane.

But what if you filled a canister to  80% of capacity with butane first?  If you filled to 80% of capacity with butane first and were exactingly careful about not exceeding the overall rated capacity, then maybe this adapter would be safe.  I'm not saying that it is safe, I'm saying that there's the possibility that the adapter might be safe -- from the perspective of the mix of gasses.  The adapter might still have other problems in terms of materials, design, and construction.  The very fact that someone put a dangerous refiller like this together suggests that they really don't know about gasses.  I have NO confidence that such a person has the ability to build a refiller that is safe in other respects.  I'm certainly not tempted to buy one.

Putting it into perspective
Now, am I just a "Nervous Nellie?"  Maybe this is actually pretty safe, but you know this is modern society, and we have to protect people from themselves, don't we?

I submit to you that I am no Nervous Nellie.  I refill my backpacking canisters all the time (with butane!!).  I use a windscreen with my upright canister gas stove.  I sometimes use my stove inside a tent.  In other words, I do all sorts of things that manufacturers tell us not to do lest doom and disaster overtake us.  I do things like refill, use a windscreen, and cook inside my tent because I've studied the objective dangers and found them reasonable for a person who is careful and has an understanding of how to mitigate the dangers.  But I will NEVER fill a standard backpacking type canister with 100% propane.  It's just too dangerous.  Period.

This refill adapter is:  NOT recommended (in the strongest possible terms).

I thank you for joining me on another Adventure In Stoving.

HJ

Butane Adapters III -- Upright Canister Stoves

The last two adapters I reviewed (see:  Butane Adapter Warning and Butane Adapters II) were really for remote canister stoves -- stoves where the fuel and the burner are physically separate and a fuel hose runs between the two.

What about upright canister stoves, what's available for them?   An upright canister stove is the type where the stove screws right into the top of the canister.  With a "long" canister like the cheap 100% butane ones, it's most practical to lay them on their side -- which would leave your stove pointing sideways.  What we need is an adapter with a 90° angle.

Turns out there is just such an adapter.

A butane adapter intended for upright canister stoves

This one, unlike the last two, isn't too bad.  Let's have a look.

The legs fold up underneath for storage.  Nice feature.

A butane adapter for upright canister stoves with the legs folded underneath.

How does it work?  Like the last adapter I reviewed, this adapter has two hooks, a larger and a smaller.

This butane adapter has two hooks, a larger one (bottom) and a smaller one (top).

The larger hook at the bottom clips onto the collar around the valve on the canister.  The smaller hook fits through the notch on the canister.

The smaller hook fits through the notch on the canister.

The canister is then rotated about 1/16th of a turn to the right, locking the canister in place.

A canister rotated and locked into place on the butane adapter.

The top of the adapter has a threaded connector, a connector that is the equivalent of the connector on the top of a standard threaded canister.  One nice thing about this adapter is that there is a valve inside the adapter.  In other words, if you hook up a canister of gas, it won't spray all over if you didn't hook up the stove first.

The threaded connector on top of a three legged butane adapter.

Note that the body of the adapter is plastic.  I have read reports on the internet of the plastic melting when used with a larger pan, particularly with simmering type cooking.  Use caution on long, slow burns, particularly with larger pots and pans.  Larger pots and pans may reflect a lot of heat back to the adapter.  I have not personally had any problems with the plastic melting.  If one were using a stove that has a significant amount of thermal feedback, perhaps something like a Coleman F1, there might be melting problems.  A melted adapter could cause a gas explosion.  Monitor the adapter closely the first time you use it with any given stove.  

Well, let's hook it up and see how it goes.  Today's stove is a Markill Hot Rod.  Note the striking similarity of the burner to the burner on a Vargo Jet-Ti, a Kovea SupaLite, and a Snow Peak LiteMax.  Note also the similarity of the valve to the Snow Peak GigaPower (GS-100) stove.  Apparently, stove companies contract out their work to a relative few factories in Korea and China.

A Markill Hot Rod upright canister stove

Ah.  There we are, all hooked up.

An upright canister stove hooked to a cheap 100% butane canister via a three legged butane adapter.

And, when we open the valve on the stove, it fires up nicely.

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An upright canister stove running on cheap 100% butane.

Stoves lose a great deal of efficiency if there's any wind, so I normally use a windscreen.

A windscreen in use with a stove running with a butane adapter.

With a windscreen, you could get heat build up that could a) could melt the plastic adapter or worse b) overheat the canister.  Overheating a canister could result in a catastrophic explosion.  Monitor the canister temperature frequently and consistently with your hand.  If it feels hot, TURN IT DOWN immediately or open up the windscreen more.

I experienced no problems with the set up above on a relatively cool day (approx. 50F/10C ambient temperature), with the stove shown.   Every day and every stove is different.  Monitor your stove closely.

DISCUSSION
This adapter is clearly the best of the lot.  It has an internal valve so you won't spray butane all over if you forget to hook up the stove first.  It has legs that are reasonably stable and prevent the canister from rolling.  Recall that if the canister rolls, you could have a dangerous, uncontrolled flare.  I can see that this adapter could be useful for day hikes, picnics, car camping, motor touring, etc. in warm weather (recall that 100% butane needs to be at or above 40F/5C for there to be sufficient operating pressure and that the canister will chill with use).

However, for serious backpacking, I don't see it, at least for me.  First, it's extra weight (78g/2.75oz).  Second, it's more bulk.  Third, it's extra fiddling (not bad though).  Lastly, that connection is not as secure as a regular backpacking connection.  In field conditions, could that connection work loose?  Somewhat unlikely, but it could happen, and that could be bad, very bad, if the gas were to continue to flow but the connection were loose.  Something to at least consider.

I will give this adapter a somewhat tentative "recommended" rating.  It is up to the individual to determine whether the adapter is useful for his or her particular style of stove use.

Thanks for joining me on another Adventure in Stoving.

HJ

Technical Appendix -- Weights

Here is a table of weights of some of the adapters and accessories I have recently discussed.

Brunton Canister Stand       19g/0.67oz

Butane adapter, no legs      29g/1.02oz

Butane adapter, two legs     38g/1.34oz

Butane adapter, three legs   78g/2.75oz

Kovea propane adapter       105g/3.70oz

Brunton Stove Stand         145g/5.11oz

Butane Adapters II

In my last post, I took a look at one of the various butane adapters on the market.  In this post, I'd like to take a quick look at another type of butane adapter, the type with two legs as shown in the photo below.

A two legged butane adapter (lying on it's back)

This type of adapter has a larger hook that hooks onto the collar of the butane canister and a second, smaller hook that fits through the notch in the collar of the canister.

This type of butane adapter has a large hook (bottom) and a smaller hook (top).  The smaller hook fits through the notch in the collar of a butane canister.

To fit the adapter onto the butane canister, we turn the adapter 180 degrees from it's position as seen in the photo above, fit the large hook over the collar on the canister, fit the small hook through the notch, and rotate the canister approximately 1/16th turn to the right.  We then have something that looks like the below photo.  CAUTION:  There is no valve inside the butane adapter.  As soon as you put it on the canister, butane will start coming out.  For this photo, I used an empty canister.  In real life, attach the stove first, then attach the canister.

A butane two legged butane adapter fitted onto an empty butane canister. 

Now notice that unlike the butane adapter in my last blog post, this adapter has two legs.  This is good.  The two legs prevent the canister from rolling -- which could cause a very nasty flare.

You then hook the fuel hose from your gas stove to the adapter as shown below.

A butane adapter, attached to a butane canister with a stove's fuel hose attached to the adapter.

OK, so in the above configuration, you're all set to go.  Uh, except for one little thing.  These adapters are shoddy junk.  Yep, the legs are the right idea, but beyond that, the thing is junk.  They're loose and they rattle.  Worse still, they leak.  Nice legs, but there's no way that I can recommend these.  I've seen one of these that was fine, but every other one of them as been loose, shoddy junk.

Now, I got mine on eBay from a seller called Plus2City from Hong Kong.  Plus2City also appears to be behind a couple of other online sellers that sell this type of adapter.  All of the adapters from Plus2City and allied sellers appear to be worthless (or worse, dangerous) junk.  Maybe there's some other source that is producing good quality adapters of this type, but I haven't seen any yet.  Sorry to be so blunt, Plus2City, but clean up your act, and I'll put up a much nicer post.  What you're selling now is junk at best and dangerous at worst.

Butane adapters of this type are definitely not recommended.

HJ