Canister Stove Forensics Needed

[DAN-Y]

What caused this guys stove to explode?

Anyone else have a canister stove explode?

This is a PSA for anyone using a canister stove. While making pancakes Sunday morning in Killarney PP I had a rather significant problem, my stove exploded. This was a newish stove for me having only been used on two other occasions, once as a test run and once to make coffee. Since the explosion I’ve done a little reading on the subject, there isn’t a lot of information, mostly speculation that the canister can explode if it gets too hot.</p>
<p class=”s1wjcqzz-10 lkEbBw”>This is my experience; the stove was set up on a smallish table and there was a bit of wind, enough to keep the bugs away. It was warm, probably 80f/25c ish. We had a windbreak on one side of the stove and a heat dispersal plate on the burner. The canister was probably between 1/2 and 3/4 full. We’d made coffee and I was happily making my 3rd pancake. With no warning the stove exploded. You have no idea how much of an understatement that is. Luckily no one was hit with any of the shrapnel. The canister landed about 18 inches from where it started while some of the other parts were more than 60ft away. Oddly enough my pot of batter stayed in the same place but flipped entirely upside down.

Photos
I know you’re not suppose to use a wrap around windscreen with this stove, or an outback oven. In this case the windscreen blocked one side only, with less than 50% coverage and about 4 to 5” away from the stove. While I wasn’t using the outback oven or its cover I did have a heat dispersal plate on, you can see the pattern of it in the bottom of the pan I was using.

I’m not entirely convince that the canister exploded, or if it did explode it may have been secondary. It seems that the explosion was above the jet, blowing out the side and collapsing everything below it. We never found the flame adjustment control or the pancake I was cooking.

 

[DAN-Y]

[Roger Caffin]

Interesting, and a cautionary tale. The moral is at the end of this.

It is an MSR stove, and it looks like a SuperFly. I would need a top view of the stove to be more confident.

The bottom of the canister has blown off, propelling the top of the canister and the stove and the pan upwards. This was very likely due to the use of a large frying pan and a heat spreader. They reflected FAR too much heat downwards onto the canister. USER ERROR.

My article on Exploding Canisters can give you more details about this.

Short summary: the canister is rated to 50 C, and the testing is stringent. I found that the canisters I tested could get up to about 100 C before blooey. The base usually blows off as seen here. This is WAY beyond the 40 C of the Touch Test we preach here at BPL.

The upward slam pushed the heat spreader into the base of the pan: you can see the dents. Chuckle: this is known as ‘explosive forming’. The forces were so high and just slightly off centre, so the brass column or burner tube of the stove fractured.

When the bottom of the gas canister started to detach a lot of gas came out, vaporised, and the fuel/air mix exploded. This is what slammed the top of the canister upwards. The middle of the canister (at the Lindal valve) is depressed right in: the upwards force on the canister met the inertia of the stove and pot.

Don’t bother trying to blame the use of a partial windshield: it had very little to do with the problem.

Now, the moral(s) from this:
Never run a stove for any length of time without checking the temperature of the top of the canister. If you cannot touch it, it is too hot!
Do not use big pots and pans on a small canister stove without a very good heat shield between the burner head and the control valve, to protect both the valve and the canister.
If you want to do ‘camping-type’ things, like making lots of pancakes, use a flat car-camping stove, with a remote canister on a long hose, not a tiny upright walkers stove.

The user was very lucky. In another case I know about (two adjacent white gas stoves and large pots) two people suffered extreme burns. One lived a few years after the accident; the other a bit longer. I have no doubt the accident contributed to their early deaths.

Cheers
PS: this is a ‘professional’ opinion based on my experience.

[Edward John M]

Holey flying fragments Batman

Also “Pop goes the whistle” came to mind

[Jerry Adams]

Thanks for the report and explanation/moral, thank goodness no one was hurt

“Never run a stove for any length of time without checking the temperature of the top of the canister. If you cannot touch it, it is too hot!”

I thought that it’s okay for the top of canister to be hot.  I have routinely experienced that.

I thought it was that you should feel the side of the canister where the fuel is.  If that’s hot then immediately turn off stove.

80 F is pretty warm to be running stove.  More important to be careful?

This would be a case where cheap butane would be better – less isobutane, no propane.

Is a superfly stove more susceptible to overheating?

[Roger Caffin]

I thought that it’s okay for the top of canister to be hot.
Oh yes, but what is ‘hot’?
By DoT regulations (the stuff has to be transported), the canisters MUST be safe at 50 C. Very hard rule. If something is over 40 C you cannot keep your finger on it: that is the ‘ouch’ point. Hence my Touch Test (patent pending …). You should apply it to the top of the canister, which will be the hottest part.

If you move the canister at all the fuel will slosh and hit the hottest part of the canister. Worry about that.

Propane boils around -40 C while butane boils at 0 C, so butane is a bit safer. But if the canister bursts, who cares? You have an explosion and a fireball.

I am not keen on the way the Superfly connects to the canister – I think is is a bit less secure, but that is not relevant here. I believe it was reflected heat from the pan down onto the canister which did the damage.

What few understand is the explosive power in a single gas canister. Seal up a house and empty one or two canisters into it, let it mix, and make a spark. The ensuing fuel/air explosion will destroy the whole house. There is a lot of energy there. Handle with care!

Cheers

[Jeff McWilliams]

Roger – I have one of your earlier remote canister stoves with the FMS-116T style head.  How would you rate it for “prolonged” cooking use?

I’ve never made batches of pancakes with it, but I’ve used it with a fry-bake pan to make a pizza or two.  Flame is set to a low LOW setting, burner & pan surrounded by windscreen and sitting on reflective base, carbon felt “hat” on the fry-bake pan’s lid to retain more heat.

Is/was your vortex burner design any better or worse or long, low heat type cooking?

[Roger Caffin]

Hi Jeff

There is a huge difference between an ‘upright’ canister stove and a ‘remote inverted’ canister stove. Really huge.

The obvious difference is that the canister is well-removed from the heat of the stove – assuming you did not put it (the canister) next to the burner of course. That means the hazard of overheating the canister is pretty well non-existent. This is a big safety feature apart from anything else.

In fact, I often nudge the canister a LITTLE bit closer to the stove just to warm it up a bit (by radiation). This slightly increases the pressure in the canister, giving a better fuel flow. But I am talking about getting the canister up to 10 – 20 C when the ambient is at -10 C – mid winter in the snow fields.

In fact, you WANT the stove body to get a bit hot so the liquid fuel coming down the hose boils before it reaches the jet. This is basic to the whole concept. This is normal and expected for most any remote inverted canister stove, but almost the complete opposite of what you normally want with an upright canister stove.

Now, there is obviously a difference between my V1 stove with an FMS-116T type of burner and my V2/V3 vortex burners, but this difference is not really significant in this context. In both cases you need the stove body hot enough to vaporise the liquid fuel. The materials I have used for the stove body are aluminium, PFA (plastic hose), SS braid and Viton O-rings. All of these can handle close to 250 C working conditions: their selection was not an accident.

I would EXPECT my stove bodies to get to about 100 C in use. That would be quite suitable. You can test for this with your finger again, with the ‘sizzle’ test. Wet your finger (spit will do), briefly touch the stove with your wet finger, and see if there is a sizzle.

What about long, low heat cooking? Fine, no worries – see above. Bear in mind that the rim of a vortex burner will be glowing bright red anyhow (by design)!

Cheers

[Jacob D]

Holy *

Glad to hear nobody got hurt. That must have got your attention! A good reminder to all of us to be safe with the stoves.

[Eric Blumensaadt]

HOLY CHIT Dan!

It’s scary for me too B/C I use that same heat diffuser from my Outback Oven ON MY CANISTER STOVE (but not the fiberglass cloth oven cover).

I guess from now on it will only sit on my MSR UNIVERSAL remote canister setup! Thank you for this post.

 

 

[Roger Caffin]

What I do NOT understand is why anyone would use a ‘heat diffuser’ when just turning the flame down would do the same thing.

Cheers

[DAN-Y]

What I do NOT understand is why anyone would use a ‘heat diffuser’ when just turning the flame down would do the same thing.Cheers

So the entire pancake would cook at the same time. Turning the flame down would cook only a silver dollar size pancake :-) Cheers

[Roger Caffin]

Oh, for heavens sake! Pick the pan up and move it around. You can spread the mix around at the same time. Same with omelettes over a gas flame (or a wood fire).

Cheers

[Jon Fong / Flat Cat Gear]

Hot spots can develop when you are using a stove with a small burner heat.  My 2 cents

 

Left – no diffuser plate, right – diffuser plate.  This was done about 4 years ago.

[DAN-Y]

Oh, for heavens sake! Pick the pan up and move it around. You can spread the mix around at the same time. Same with omelettes over a gas flame (or a wood fire).Cheers

Shoulda posted that instead of previous comment :-) cheers

[Eric Blumensaadt]

WHUT DAN SED.

[David Thomas]

I found a diffuser very handy in one application – heating water in an automotive radiator over a 130,000 BTU/hour (38 kW) propane burner as part of my remote hot tub set up.  Otherwise, the heat was too concentrated on too very tubes in the radiator, the water would boil in those tubes, the steam was insufficient to absorb the heat and some of solder melted.  (Resoldering the tubes and) using a flame spreader – a large flat rock – fixed the problem.  Very UL, since it was a rock found and left on site.

But other than that?  Yeah, move the pan around.

[Jan Rezac]

I did a bit of research on this as I was thinking about using heat diffuser for frying in a Ti pan, and it seems quite obvious how the overheating could happen. The energy radiated by a heated body grows with 4th power of its temperature. A pot filled with water won’t get much above the boiling point, but the diffuser may get red hot, so the difference in the heat radiated down onto the canister is huge.

I’ve seen in the forum somebody using a heat shield above the canister (a circle with a hole sitting around the valve of the canister) as a part of some windscreen system, it would be wise to use such a shield whenever a diffuser is used. The temperature of the stove itself in such a setup should still be monitored, though.

[Gary Dunckel]

The Backpacker’s Pantry stainless steel heat diffuser does indeed spread the stove’s flame out, but I’ve found that I must use a very low flame. My favorite stove for this is the now-discontinued Coleman F-1 Powerboost, which offers superb simmering ability. I made a custom wind screen for it, which works well for both my MSR Titan kettle and my favorite bowl/pot, the Snow Peak bowl with handles.

On one backpacking trip with my buddy, after I simmered my meal and shut the stove off, my friend decided to boil some water for some coffee. He didn’t think to remove the diffuser, and he fired the stove up at high output (he never gets the lesson about running stoves at low-medium flame settings). His water in the Titan kettle did boil, but slower than usual due to the diffuser blocking the direct flame. Later, I noticed that some of the hard plastic on the stove body almost melted. I think his high flame setting allowed the heat to bounce off the diffuser, big time. We were probably lucky that the canister didn’t overheat.

So the lesson here is… don’t be stupid around stoves.

[Eugene Hollingsworth]

Quote of the Day:  “Oh, for heavens sake! Pick the pan up and move it around.”

…and to think I’m considering a luxury treat of popcorn in a wide titanium pot. I’m sure not going to let that sit…

[Eugene Hollingsworth]

It really is a miracle that no one was injured from this explosion. Someone’s guardian angel was on the job. Thank you for the PSA.

This example is a strong reminder for me to use the above-tank heat shield that I made, just because I’m aware that mistakes can happen. The windscreen I use has most of the canister area exposed to cross breezes also. Between those precautions and due diligence of checking the canister temp I should be safe.

But still… pictures of blown canisters like this really make a person re-evaluate assumptions of safety on these top mounted stoves.

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