Wednesday, 22 December 2010

Inverting the Spider

In super cold conditions the efficiency of the Primus ExpressSpider remote canister stove can apparently be increased by inverting the gas canister. I've only see a couple of ways of doing this and nothing is commercially available so I'm interested in your ideas.

 

My first idea was to use the Primus Clip-on windshield that I use with my Optimus Crux top mounted stove. This has the advantage of being very easy to store as it can be clipped flush around the canister when not in use. At 60g it's not too heavy to carry but not too stable either when used in this unconventional way.

In accordance with UL principles inverting the canister should ideally be achieved by using items you're already carrying. I tried this by utilising two velcro ski straps and three titanium V-pegs. This set-up proved to be far more stable but fiddley to set up with cold fingers. The other problem is that I don't usually carry these small pegs in winter although at 36g for the three pegs (I'm already carrying the ski straps in winter so their weight isn't included) it's not a hardship to carry them.

So how do you invert your Spider?

14 comments:

Chris Townsend said...

I've been inverting cartridges with stoves like the Spider for several years. I must admit I generally just prop the cartridge up against a boot or the pack or other object. The easiest to use of course is the Coleman Fyrestorm is this is designed to be used with an inverted cartridge.

Maz said...

I saw both of these ideas on Backpackinglight.com although they used hook pegs which are lighter, if you got the Vargo Titanium pegs, at 6g each so I guess you could use those. That said, and perhaps this is me being stupid, but why not just hold it? It's not that long a boil time and there's nothing to carry or set-up and less to go wrong...

ADVENTUREinPROGRESS said...

I don't have the Spider, I have the MSR WindPro. I use either the tent stake method you describe, or like Chris, I just prop it up if I am feeling lazy.

Dave Hanlon said...

I've used gas in deep cold on just one trip (Oyer Fjell Feb this year). Not the spider but a Primus Gravity. I avoided the issue of thinking up a proper solution by putting the canister in the top of my boot or sitting it on the stoves stuffsack balanced in a (cunningly crafted) impression in the snow.

Joe Newton said...

Chris - The Fyrestorm caught my eye last year and is on my list as an option. Jorgen lent me this Spider to try this winter.

Ahh, using my boots seems so obvious now! Dual purpose!

Maz - I agree, I'm starting to think that 'no' system of holding the canister in an inverted position is the lightest!

Damien - another vote for using boots. I'm liking this idea.

Dave - another vote for using 'initiative'. Initiative doesn't weigh anything either...

samh said...

The tent stakes and velcro is great, Joe. I usually just rest mine against some objects that are lying around me but that can be a little sketchy at times so your solution might be a good one.

Mac E said...

I haven't actually used anything to invert a gas cannister but came up with this made from a piece of closed cell foam.

http://farm6.static.flickr.com/5089/5283280343_d53a9903b4_o.jpg

http://farm6.static.flickr.com/5284/5283879086_f55be4fdd9_o.jpg

Of course it isn't dual purpose.

BG! said...

Here you go:

http://beardedgit.smugmug.com/General/miscellaneous/gasbag001/1134684754_BgKBD-X3.jpg

and

http://beardedgit.smugmug.com/General/miscellaneous/gasbag002/1134685090_Fj6qN-X3.jpg

It's one of those mesh-bags that used to be in packs of washing-powder tabs. I hang mine from my ice-axe, if I'm axe-less I'll use a stick or occasionally a pack.

As is, it's a huge 7 grammes. Superduperuberlightweighters can get it down to 4 grammes by ditching the toggle but I like to keep it on as it permits height-adjustment. The bag stays on the canister, so there's minimal set-up time.

Oh, and no boots are involved, which means that you can cook AND have dry feet :-)

Martin Rye said...

Stef you're a genius. Still I like the Primus wind shield idea. 60g is a killer to carry mind you.

Huib said...

Joe, can you tell me how you ignite the stove with an inverted canister? Is it ignited with the canister upright or inverted? And are there any risks when you use your stove with the canister inverted?

Joe Newton said...

Sam - I'm liking the idea of just propping it up on something. No weight penalty! I've just tried using my bigger MSR Blizzard snow stakes and the ski straps and that works too.

Mac - great idea! I was wondering if it could incorporated into some kind of canister cozy but the more I look into cozies I'm realising that they might not actually work with increasing the stoves efficiency. CCF is nice and light.

BG! - the laundry baggie is a great idea! Hanging the canister instead of supporting it is thinking outside the box, I like it. Maybe I can hang it from a point near the tent's entrance...

Martin - the windshield almost works perfectly. Primus trimmed the corners (I'm guessing to reduce sharp edges) but it reduces the stability just a wee bit. Compact to carry though.

Huib - in the few test firings I've given the stove I have lit it upright and inverted with no problems. If you have a BPL subscription you can read Roger Caffin's complete article here:

http://www.backpackinglight.com/cgi-bin/backpackinglight/selecting_stoves_for_cold_weather_part_2.html

But his thoughts on lighting inverted canister stoves are summarised here:

"I first make sure that I can turn the valve on with one hand: some valves can be a bit sticky at times. Then I light my butane lighter (which has been warmed up in my hand) and hold it to the burner head, and then I turn the gas on gently. The liquid gas expands as it comes out of the valve and down the tube, with the propane boiling off somewhere along the way. This propane gas gets to the burner head first and is lit; the heat from the flame on the generator tube then makes sure the rest of the gas mix is vaporized. You light a petrol stove the same way. If you wish you can start with the canister upright and turn it upside down after the stove has been burning for a few seconds - but do this gently and watch the flame height. You may have to turn it down a little once you have inverted the canister."

Huib said...

Hello Joe, I will give a lecture on cold weather camping at an outdoor show in the Netherlands soon. I would like to use two pictures from your website to show in my PowerPoint Presentation. After the outdoor show a short version of the presentation will be available on the website of my backpacking club. The two pictures are of the inverted spider and of the Bushbuddy stove. Do you allow me to use your pictures?

Joe Newton said...

Huib - I have no problem with you using those two images as long as you credit them to me at this blog! I'd like to see how they'll be used in the presentation when it's complete so get in touch when it's done. Good luck!

Huib said...

Hello Joe, I would like to mail you about my presentation but unfortunately I cannot mail you using the Blogger account. I tried to find you on Facebook but there are a lot of Joe Newtons out there. Can you try to find me on FB? My profile picture on FB is the same as on Blogger.