Has anyone had problems using shielded canister stoves at high altitudes?

Spitballing here, but I suspect that the windscreen is not the problem.  Do you remember the time it cook to boil and how much water you were heating?

The TOAKS stove is relatively new and there is not much customer feedback on performance.  IMO, the TOAKS stove is an odd duck, they use a lot of good materials but I am not impressed with the burner.  At low gas flow, the individual jets look great, at high flow rates, they disappear and merge.

I tend to believe that if the pitch changes when you lift the pot, then you are impacting the burn dynamics.  I suspect that the stove would then be running too rich.  If you get back to higher altitudes, you might be able to test with and without the windscreen.  My 2 cents.

did you try removing the windscreen when you were at high elevation?  That would rule out whether the windscreen was causing the problem.  If it wasn’t windy.

what you said is really weird.  it doesn’t make sense.  Maybe there’s some totally unrelated problem like there’s something wrong with the stove.  But then it wouldn’t work back home.  unless the failure is intermittent.

just looking at your picture, there is plenty of air getting into the stove, no way your screen could be blocking anything.  Nice windscreen.

 

The TOAKS stove is relatively new and there is not much customer feedback on performance. IMO, the TOAKS stove is an odd duck, they use a lot of good materials but I am not impressed with the burner.

I was hoping Jon Fong would chime in here. I agree with his assessment of the Toaks Stove. I had one briefly, but got rid of it after deciding it wasn’t for me.

Aside, I use various canister stoves all the time at elevations well over 8K with no problem, including with various windscreens. As was mentioned, try it without the screen next time?

But if it doesn’t break the budget perhaps pick up an MSR Pocket Rocket Deluxe or Soto Wind Master… they do fairly well in light wind without a windscreen, and are proven performers. With a windscreen they’re even better. I have both.

Yes, this is puzzling. I tested the Toaks again and it worked as expected. Then I tried to suffocate it with my old, taller full-wrap windshield (see photo), but it worked fine.

Maybe there was an intermittent problem with the fuel—moisture or something. Next season, I’ll try the Toaks at 8,000 ft with a fresh canister with and without a windshield and see what happens.

BTW, I have no shortage of stoves. My first canister stoves a Pocket Rocket 2. Then I got a Hornet II, attracted by its lower weight—1.7 oz vs 2.6 oz. This worked well with a windshield. Then I tried the Toaks—same weight as the Hornet II, but smaller burner-to-pot distance and better build quality. REI has the Toaks in stores, so I was able to take a good look at it.  I fired it up in my shed and was impressed by its smooth, violet flame pattern.

So … Jon, Brad, what are your reservations about the Toaks?

The TOAKS Ti Backpacking stove is in my opinion on par with the BRS 3000t: not great but ok as a fair weather stove.  All stove will perform fine in calm conditions, good stoves work in extreme conditions.  The Pocket Rocket and the Soto WindMaster have earned their reputation, TOAKS has not.  Fire Maple makes some very good stoves as well and out perform TOAKS.  My 2 cents.

I’ve used a Soto Amicus and a Pocket Rocket Deluxe above 11,000 feet with no issues other than the piezo not functioning up high. I was not using a wind shield but I was using a heat exchanger pot.

If the wind shield was at least partially open I doubt that was the cause.

Guys, thanks for your thoughts. I’ll do some more testing when I get back up to altitude, which alas, probably won’t be until next season.

Consider taking a 2nd known stove (PRD or Soto, perhaps borrowed) up to altitude to be a control for smooth burning. It’s < 3 oz extra carry one time for definitive experimentation

Separately commenting on ignition, not all piezo are equal on spark energy. When I used Jetboil, > about 9k ft altitude defeated their piezo ignition energy. In past decade, PRD piezo has been reliable near treeline, say 11,800 ft. Still, i carry a small, light ferro rod as backup.

This is from Roger from a few years ago……

The problem with altitude is well-known and can be scientifically explained.

First of all, you can not light just any fuel/air mix. If there is a lot too much fuel or too much air, it won’t light. That is, if the mix is too rich or too lean. In fact, there is an optimum fuel/air ratio where ignition is easy. As you go away from the optimum, it takes more starting energy to get the mix to burn.

Second, the spark you get from a piezo-ignitor does not have a lot of energy. If you are close to the optimum fuel/air ratio, then the spark has enough energy and the stove lights. But if your fuel/air mix is a long way from the optimum, the spark may not have enough energy.
At altitude the air pressure is lower, and this changes the fuel/air ratio: it becomes very lean. This makes it hard for the tiny spark to light the mix. In the other hand, a Bic has lots of energy and will always light a stove.

Aha! Can you reach an altitude where the spark in a Bic can’t light the butane fuel in the lighter? This is less likely to happen (or more difficult), as the spark starts very close to the fuel and there is a wide range of mixture as you go through the stream. In most cases the spark will find a suitable part of the mix before it goes out.

Also, the flow from a BIc nozzle is at a much lower speed than the flow from a stove burner head. The high flow from a burner head cools the spark faster.

What this can mean in practice is that careful adjustment of the spark gap on the stove, plus a very low flow of fuel, can often be enough to light the stove. That is why many piezo-ignitors have their tips very close to the metal of the burner head.

I would imagine also that some ignitors have bigger piezo crystals than others, meaning they can put more energy into the spark. That seems logical, but it makes the ignitor more $$.

Cheers