Wednesday, 18 May 2011
Primus Express Spider, Review
The Primus Express Spider has been available for some time now and while I’d read the reviews I’d never actually tried one. I was offered one for review by Millets so I was looking forward to seeing how it performed.
The Express Spider has a few features that set it apart from basic canister mounted stoves, the 1st and most obvious is that the burner isn’t directly attached to the gas canister but is instead connected via a flexible fuel line, the 2nd useful feature is the pre-heat facility which helps maintain performance or in some cases allows the stove to actually work in temperatures below freezing when a canister mounted stove could fail completely.
I guess most people considering the Express Spider do so for its cold weather ability but it has something to offer even if you only use it in mild conditions. As it’s a remote canister stove it sits much lower than a canister mounted stove which not only improves stability but also makes it easier to use in a small porch such as those in some solo tents simply as the burner being lower is further from the flysheet. The pre-heat feature while it’s designed mainly for colder weather is also beneficial when it comes to using the last few grams in the canister.
I’ve found in the past with canister mounted stoves that when you get down to the last 10g or so of gas the reduction in pressure in the canister means that there’s insufficient fuel flow to keep the stove burning, it’s not unusual to remove a seemingly empty canister yet when you shake it you can hear that there’s still fuel remaining. What the pre heat function does is allow you to invert the canister, the fuel then flows along the fuel line as a liquid until it reaches the pre-heat tube where it vaporises (becomes gas again) and can burn as normal.
When it comes to low temperatures what can happen is that as the canister itself cools the pressure in the canister drops to the extent that there’s insufficient fuel being delivered to the burner head, this results at best in a slower boil time but the side effect of that is that the longer it takes the colder the canister becomes and thus the pressure continues to drop, eventually the stove will stop even though there’s plenty of fuel remaining. In this situation you can simply invert the canister as you would if it was almost empty, the fuel is delivered as liquid until it reaches the pre-heat tube where again it vaporises and is once again burned as gas. Without a pre-heat tube inverting the canister simply results in liquid gas arriving at the burner head and the result is that the stove flares up which definitely isn’t something you want happening when you’re trying to cook in the porch of a small solo tent.
The Primus Express Spider comes supplied with a small stuff sack that from the outside looks like mesh but on the inside it’s actually plain fabric, I’m not sure why its mesh on the outside but plain fabric on the inside means that the stove is easy to remove and pack as it doesn’t get caught up in the mesh.
The stove itself is really well made and is devoid of any unnecessary features, someone said that a product had reached the peak of development not when there was nothing left to add but when there was nothing left to remove, if that’s the case the Express Spider must be almost as close to the peak of development as it’s possible to get, minimalist but with no useful feature missing.
The legs all fold together for packing but when unfolded each have a stop position to ensure that they’re as stable as possible, being a tripod design means that it’s stable even on a rough surface. The burner head is quite small, smaller than I’d probably prefer as this is a stove I’d use with a wide shallow pot rather than a tall narrow one, 2 reasons for that, 1. A wide shallow pot is more stable and 2. A wide shallow pot is better if you want to melt snow (this is a stove aimed at use in lower temperatures after all) That said in use it seems to work just fine although I’d be inclined to run it at less than full power. One final design feature that I like is that both burner and the fuel valve/regulator can rotate on the fuel line with the result that once set up there’s nothing trying to tip the stove over. Perhaps the only thing I’d like to see changes is the position of the fuel valve, rather than a vertical valve I’d prefer a horizontal valve as it’s easier to operate with the canister inverted, that said it’s not a deal breaker by any means.
With all the potential advantages why wouldn’t anyone want to use a remote canister stove? Well it comes down to bulk/weight over a canister mounted stove. On the issue of bulk the Express Spider fold up so well that it’s hardly an issue, in fact I have a canister mounted stove that while being smaller is more difficult to store due to the larger diameter burner head. If bulk/packed size isn’t an issue them what about the weight? As far as I’m aware the lightest canister mounted stove at present weighs about 48g, most however will come in at between 60-100g, the Express Spider weighs in at 191g with the stuff sack adding another 10g if you choose to use it. If not the lightest it’s certainly one of the lightest.
I’ve tested the Express Spider in what I would consider a real world situation and in breezy condition with an almost full 100g canister with the valve about 2/3rds open it boiled 500ml of water (13.5°c) in 3mins 44secs, obviously that isn’t super quick but by running it with the valve less than fully open it achieved the boil on 8g of fuel and that’s pretty impressive. Of course I nay have achieved a faster boil with the valve fully opened but I’d prefer fuel efficiency for the sake of waiting an extra 30 seconds.
Having tried it with an almost full canister I wanted to see how it performed on an almost empty canister with the canister inverted. The result really impressed me, starting with a canister that had 24g of gas remaining the Express Spider managed a boil in 3mins 47secs and used 9g of gas.
All things considered the Express Spider is definitely a stove I’d have no hesitation in using or recommending, I haven’t read negative reports on any of the blogs I follow and having tried it myself I can see why.
The video below shows the stove in operation with the canister inverted and about 20g of gas remaining. I forgot to weight the canister until I'd switched the camera off but for what it's worth it weighed 104g.