Primus express spider

I just got mine and have only tested it briefly.
It was suprisingly loud for a canister stove and boiled a liter of water in about 3 minutes and 25 second.

I haven't noticed it getting glowing hot, but then I've only run it for about 10 minutes alltogether
Just now the stove and the a halffull canister sits in the freezer for the simulated winter test… :-)

I am not sure this is proper english but ill try :)

the end of the hose that inject gas is hold by a screwed part to the stove
it was partly unscrewed
i retightened it and now it works properly.

Sounds like you were dangerously close to a catastrophe.

Glad your luck held and you took a look.

Maybe drop a line to the manufacturer and include the photo.

Hi Fred

The photo shows the stove in an extremely dangerous state. If you look at the air hole you can see a pink flame colour inside the air inlet tube. This means the flame has got inside the air inlet tube. BAD!

I suspect the trouble was the loose nut at the end of the air inlet tube, as you mentioned. This allowed the jet to point sideways enough that some gas came out the air inlet holes. It lit, and flashed inside.

Cheers

I've noticed that the Spider doesn't simmer well. In fact running it on low settings seems to make the burner head glow red in the middle and after a while the the Spider makes a coughing sound and the gas ignites below the burner head in the brass cylinder. This will then make the burner head glow a brighter red and eventually overheat it. I find this happens at the lower settings and at an specific fuel flow. If it's just a bit more it won't happen, and if it's a little less you're more likely to extinguish the flame… At least if it's blowing outside.
In the attached image you can see the glow of the flame inside the brass cylinder right at the holes in the cylinder.

I've had no trouble running it at higher effect. In fact it suprised me with boil times at about 2:40 for a liter of water in the 2,1 l primus eta power pot and a new cannister.

My guess is that it is the same problem in the original post, but in an earlier state.

I saw this stove in a magazine, then looked into it and thought — why ?

The MSR Windpro is lighter, and the fuel valve is horizontally oriented, making it easier to invert the canister (which I've done snow-camping several times).

Am I missing something ?

I nearly bought a windpro before the express was available.
But the windpro reputation for fuel efficiency isnt that good.

I am just back from 3 weeks in Patagonia with the express, i didnt had again the same problem but i mostly used it inverted.
We are 2, and i only heat water, no cooking so i dont mind holding the canister inverted for a short time, i didnt even try to find something to keep it that way by itself.
That way i let my wife do the cooking chores , opening the pouch and mixing it before pouring the water :p.

It does seem to be an unusual design flaw by Primus – to build a stove suitable for inverted canisters, and then putting the valve in an inaccessible position.

Still, no doubt they will release a Ti Spider in a year or so, like they did right after I bought the first version of the Micron.

OK so I have the Spider also. I saw this a long time ago so I am careful to keep the threads tight all around.

The second pic where the stove is more yellow is what mine does. It burns normally but after 5min (?) the flame kinda sucks down through the mesh or something and it makes a 'wet gurgling' sound. There will be no real visible flame above the head, and the head will glow yellow.

If I turn the gas up it gets louder but remains the same.

If I turn the gas down so its almost off the flames will slowly creep back up the the top like its supposed to be, albeit on extra-low power.

It happens with a 2 liter pot. It happens with my BPL550 mug.

WTF?

Is the mesh too big? Again, I make sure all the threaded parts are tight. Its not a windscren holding up all the heat like David Drakes Giga ("jordan" windscreen)cause it happens with the little 550.

I've just been turning down the power and it fixes itself as long as I keep the power on low.

Its a remote can so I am not woried about blowing up, it makes me nervous though.

thoughts?

EDIT- Jerry you can help too!! :P

"EDIT- Jerry you can help too!! :P"

You're a trouble maker encouraging me to speak up : )

Greater Mount Tabor – you must be a fellow Portlander

I dunno – stove doesn't look right though

"OK so I have the Spider also. I saw this a long time ago so I am careful to keep the threads tight all around."

I have an Exponent F1 that leaks between stove and canister and produces a large flame from there, or leaks out all the gas overnight if I leave it screwed on, but that's different than your problem, but now I am very carefull to fully screw on the stove without over-tightening

Hi all

BAD BAD BAD

Take a look at the air inlet in the photos. You can see flame in there. The flame is inside the burner! That is extremely dangerous!

Hum … not sure why this is happening to several people. It would seem that the flame can bounce off the underside of the pot and get down to the air inlet holes. That's BAD design.

You could try puting some fairly fine SS mesh around the inlet tube. This should, normally, prevent flame from getting inside the burner tube. If you could stand it off a little from the burner tube there would be no effect on the amount of air being sucked in.

'fine mesh': a mesh of fine SS wire and holes ~0.5-0.8 mm pitch. Not over 1 mm I think.

I can't look at this in more detail right now – sorry. I did not have this problem with mine. But it would suggest great caution is required.

Cheers

I have encountered this problem a couple of times. It does not occur when the stove runs at high power, It happened when I set it to simmer or when there was only little gas left in the canister. Only some time after that I learned here that I’m not alone.

I like the stove and I have built a nice system around it (see this thread), so I looked for a way to fix it rather than get some other stove.

It seemed that the flame gets inside the burner through the mesh backing the jets, not through the air intake holes as someone suggested here.

I have replaced the mesh with a finer one. I have used a mesh from a stainless steel tea strainer, the holes are about 2/3 the size of the original mesh. Opening the burner was easy (but it took a lot of much more complicated trials) – I just squeezed it slightly in a vice and the upper part popped out. I replaced the mesh with a new one cut to size. I had to add a ring made of a strip of thin SS sheet around the inner circumference to hold the mesh in place (the original was spot welded to the burner I guess). Then I just pressed the burner top back.

I have tested it by letting the stove burn for some time at the lowest power. Previously, I was able to reproduce the problem this way – the burner got red hot and then the flame got inside. Now, this does not happen any more and while it gets red hot, the flame stays where it should.

I’ll see how it stands up in long term use. I hope the new mesh is durable enough; it is a bit thinner than the original one.

I have a Primus ETA Paclite which I think has a similar burner design … I'll have to check it out to see if it's doing this. I've never inspected the burner with a pot on it.

Kind of terrifying.

As a sidenote – the Primus valve design isn't terribly well suited to inverted canister mode – I've yet to try it to be honest but I'm not sure how I'd keep the canister inverted and still retain any ability to control the output.