Primus ExpressSpider Stove

Image courtesy of Manufacturer

By Dave Wilkes

While in Central California (San Luis Obispo) for a family weekend, a Primus Express Spider with “windscreen” from North American Gear, LCC was delivered to my door for me to review and it looks to be everything I had expected based upon the reading I had been doing about this product.

Description and specifications from manufacturer’s website: http://www.primuscamping.com

A sturdy alternative to top-mounted gas stoves

The ExpressSpider is one of the lightest hose-mounted gas stoves available. As its name indicates, it uses the same technology as our ExpressStove topmounted gas stove. And it lives up to its name by being a really lightweight stove that’s also extremely stable and durable, thanks to its well-planned construction. Comes with a heat reflector and nylon stuff sack.

FEATURES

• Weight: 198 g / 7 oz
• Output:      2000 W / 7150 BTU/h
• Boiling time: 4.5 min
• Dimensions:          105 x 85 x 55 mm / 4.1″ x 3.3″ x 2.2″
• Ignition: Manual
• Suitable for: 1-4 People

MSRP (US$) $60.00

Measured weights:

Stove only: 196g / 6.9oz

Pack weight (stove, windscreen, sack): 228g / 8.0oz

This stove is a pressurized gas canister type stove but is unlike many of the canister stoves now available. In fact it is more like some of the liquid gas stoves I have used in that the stove itself is separate from the fuel container and connected by a flexible metal fuel line (incased in a metal mesh sheath), and it has a fuel preheating tube. The stove itself consists of three folding legs that also act as a pot stand, a central burner, and unlike any other canister gas stove, a preheating coil that passes over the burner to pre-heat the fuel. In addition to the stove itself the box contained a small stuff sack and a “Wind Screen”. The stuff sack is a small black nylon bag with a mesh outer layer, and has a drawstring closure. The “wind screen” turns out to be a round sheet of aluminum intended to be placed under the stove (I will go into more detail about this later).

Stove in 900ml Ti pot

The stove attaches to the fuel canister using what I have seen referred to as the “universal” threads. While not actually “universal” since there are fuel canisters that are incompatible, it is the most common and as such, the stove is compatible with fuel canisters from multiple manufacturers. This is a good thing for me since no place locally carries Primus fuel canisters. For my first use, I attached the stove to an almost empty JETBOIL 4 season fuel canister (3.53 oz / 100 g) that I already had on hand. In addition, I purchased an 8.1 oz (230 g) fuel canister by Burton (“High Performance Fuel Blend”), bigger than I will probably use for hiking or backpacking, but a good size for experimenting with the stove at home and maybe while camping.I have read that one of the advantages of this stove is that due to the fuel canister being separate from the stove the canister can be inverted to improve its effectiveness when it is cold or low in fuel. However, I found nothing about this in the instructions, even though there is a section in the instructions about cold weather usage. Since this is new to me, it will be something I intend to test…with extreme caution.

Instructions:

I enjoy reading instructions that are clearly not written/translated by a non-English speaker. Some of the terms and wording used can be interesting and fun to read. Sometimes this language barrier can cause a problem with the instructions being unclear or even wrong. This is not the case for the Primus, while some of the wording sounded a bit odd to me, I could not see anything that affected my understanding of the instructions. However, I think the instructions do miss a key piece of information. In the section that describes dissembling the stove to clean the jet, it does not describe how the jet is to be cleaned; it simply says “Clean the jet”. While on the topic of instructions, I found it interesting that the assembly instructions say to use soapy water to check for leaks when attaching the fuel canister…while I can understand the desire to be safe, I don’t see this as being reasonable for a backpacking stove.

Setting up the stove:

I found setting up the stove for the first time quite simple. I found it to be quite intuitive and am sure I would have had no trouble doing it without reading the instructions. To assemble, unwrap the fuel line from around the stove and extend the legs (that also function as pot stands). Then verify the fuel valve is turned off, and screw the fuel canister onto the valve section. To light, simply turn on the fuel while holding a flame to the burner.

Note that the valve section has a gasket to insure a leek free connection. I wondered if the gasket could accidentally fall out and tried to see how easily it might come out. I found I was unable to remove it easily and did not want to risk damaging it so did not try too hard. I am confident that it is unlikely to fall out on its own, but I will be keeping an eye on it throughout my review anyway.

The stove itself is very light. In fact I found that the aluminum “windscreen” when unfolded and flattened as much as I could by hand, would actually prevent the stove from sitting flat. The weight of the stove alone is not enough to fully flatten the aluminum, and so it tends to lift one or more of the legs off the ground. Putting a pot of water on the stove overcomes this and the setup seems stable (at least on a table and my porch, we will see how this does under actual backpacking conditions where the ground is often uneven). I really don’t get calling this a windscreen, since it sits under the stove it can’t possibly block wind, it is more of a stove base/heat reflector. On the other hand, I once had a bad experience while priming my liquid gas stove and some of the fuel leaked on the ground and the pine needles caught on fire, so I have taken to carring something non-flammable, along the lines of this “windscreen,” to put my stoves on. In addition, the bottom of my Ti pot is very thin so I am thinking that this could act as a simmer plate to help better distribute the heat when cooking and/or simmering.

Regarding pots:

I recently picked up a GSI Haulite Minimalist cooking set. Sadly the 3.5” pot is a bit small for this stove and so is too unstable for me to use. However my 900ml TiWARE titanium pot (5.5” diameter) fits quite well on this stove and so this is what I will probably be using for most if not all of this review. The stove when packed fits in my Ti pot with room to spare, but unfortunately not enough room for the 100g fuel canister.

So far I have not been a big fan of canister stoves. To start, they can be greatly affected by cold weather, and even the so called “4 season” fuel mixes are only partially effective in cold conditions, often using up the cold weather part of the fuel leaving the rest of the fuel unusable except in warmer conditions. Another thing I don’t like is that these canisters are not refillable, andthis creates two issues. First is the obvious waste involved in using and disposing of the canisters (NOTE: if drained and punctured, they can be recycled). Second is what to do with partially full canisters. It can be difficult to judge how much fuel is left in a canister, and I don’t like the idea of carrying one of these steel canisters for miles up a trail only to find there is only enough fuel left for 1 or 2 meals and then having to carry the empty with me the rest of the trip.

So why am I reviewing this stove especially with winter right around the corner you might ask? That is a fair question. After reading about this stove, I was intrigued by a few of the features. First is the preheating tube, intended to make the stove more efficient and possiblly work better in cold weather. Second is that since the canister is separate from the stove, a wind screen can be used to improve the stove’s performance and efficiency (making it odd that the manufacturer does not include an actual wind screen with the product but they do offer one as a separate option). Third is that since the canister is separate from the stove, it can be used in an inverted position so that in cold weather the liquid portion of the fuel is used first thereby improving its effect and allowing the use of all of the fuel in the canister instead of only the portion that will vaporize at the given temperature. [I won’t bore you by going into the details of how the different fuels function at various temperatures but encourage any interested readers to research that on their own]

Dec 2 ’10

NOTE: Unless otherwise stated all of the cooking mentioned below with this stove has been in conjunction with my 900 ml Titanium (Ti) pot.

Well as I have come to expect weather and commitments have conspired to make reviewing gear difficult…but not imposable. I have been playing with this stove quite a bit at home, experimenting with what I can cook with it and how well it works with my Ti pot. What I have found is the small diameter flame combined with such a thin pot can be problematic. Ironically this is exactly what I desire for my smaller GSI Minimalist pot, but the diameter of that pot is slightly too small to fit this stove safely. The center of my 900 ml Ti pot gets quite hot but the thin material does not distribute the heat well. For boiling water and heating things like soup this works fine, but for thicker dishes I have to be quite careful. I have been able to make a kind of cream of wheat using this stove in my kitchen but burnt it when I tried it while camping. However, I was able to simmer split pea soup while camping, something I have been unwilling to do with any other stove I have used, and it came out very well (nothing better than fresh hot pea soup when camping in the snow). What amazed me was how well the stove melted snow. While camping, my water purifier failed and I had to melt snow. The snow in the area was quite light and so not ideal for melting but it was all I had. So I packed as much snow into my pot as I could and added some water from the stream (to avoid damaging my pot), and lit the stove. Next thing I know, all of the snow is melted and starting to simmer!

Note the Frost on the canister

As I mentioned previously, I have avoided using canister stoves for cold weather due to how much they can be affected by the cold. I took this stove with me on a 3 day trip into the Eastern Cascades for some solo snowshoeing and camping. The fresh powder made the snowshoeing a lot of work, but the forecast (6-9” of fresh snow and “coldest air of the season”) combined with it being during the week allowed me to have the mountains almost entirely to myself. I found an abandoned camp ground just below the snow line and set up camp. The temperatures started out just above freezing dropped to below freezing that night and stayed there the rest of the trip. For this trip I decided to use the Burton (“High Performance Fuel Blend”) canister rather than the JETBOIL 4 season canister since it is bigger and I expected I might need the extra fuel. I did bring a new JETBOIL canister with me just in case the Burton one did not work, but it was not necessary. Normally in these conditions I would keep my fuel canister in my sleeping bag to help keep it warm, but since I wanted to test the cold performance of the stove I kept the stove and fuel canister in my tent. For each meal the stove lit easily and except for some sputtering worked quite well.

Sputtering?!?! Yea, I said sputtering. Something I have noticed about this stove is that some times when running at a low level the flame of the stove will “sputter”, that is flair up and down. [see attached video] At first I was concerned, but from what I can tell it does not seem to have any effect on the stoves operation, so it is more of a curiosity and annoyance than anything.

In my original posting I mentioned the “windscreen”. I have tried using this a few times but after about the second use I noticed a hole in the center where all of the folds come together to a point. Then after folding and unfolding it a few more times it split along one of the seams, so now there is a split running from one edge to the center so I have stopped using it. I have been using an aluminum wrap around wind screen from my old MSR stove, however after watching the way this stove works with its very small directed flame, I feel that except for in high winds the wind screen is probably not necessary.

I have intentionally not included fuel consumption in this review. It is not that it is not important; it is just that it is subject to so many variable factors that I just don’t see how my results will be relevant to the reader. What I will be doing is keeping an eye on how much use I get from a canister of fuel so I can predict how much fuel I will need to bring for a given trip. However I will note that after years of using my trusty liquid gas stove, I have never become very accurate at this, and so make it a habit of overestimating how much fuel I will use so that I don’t run out. So far since I have yet to empty my first canister with this stove, I don’t have much to go on.

Overall I am very impressed with this stove. It is not as small or compact as I would prefer, and it does not work with my favorite pot, but it has some definite advantages. So far it looks to work at least as well in cold conditions as my old liquid gas stoves, but with less hassle (no pumping or constant adjusting the flame, and no priming). Since the fuel is in a sealed canister, I expect the jets are less likely to clog. The stove is very easy to light (turn on the gas and apply flame) and does not seem to need time to warm up. If I were to offer suggestions for improvement I would have two. First would be that the pot stands be extended so that the stove works with smaller diameter pots. Second would be to attach the fuel preheating tube to the stove at both ends. The fuel preheating tube is attached to the stove at only one end and I have found it can be easily bent if the stove is not handled properly. I worry that I might snag it on something and bend the tube such that it crimps or breaks, this would make the stove completely unusable.

So while the stove would not be what I would consider ideal for my short solo outings, I look forward to using it to cook for a group and for longer trips (e.g. I am trying to arrange a weeklong trip next summer with my brother, and plan to use it for next year’s MT Adams climb).

SIDE NOTE: I did have one other thought about the design of the stove for a lighter weight option. Since this would require a significant redesign of the stove it is probably not worth mentioning, but I never let that stop me before so why start now. My idea is to change the connections on the preheat tube such that the fuel line can be attached directly to the stove with the preheat tube removed for use in warm conditions. Second would be to offer different sets of legs for the stove in different sizes. The user could select the size of legs that works with their pots allowing this stove to be used for large group size pots as well as for ultra light/solo use.

Dec 23 2010

So easy a 9yo can use it

After many years of using a liquid gas stove that has never let me down, and experimenting with a few other designs that good as they are, simply have not been able to replace my old friend, I was surprised that a pressure gas canister stove could possibly become my favorite stove even in cold weather. Since my last review, I have used this stove while snowshoeing a few times to make a hot lunch or hot drinks to accompany my lunch (the ultimate extravagance for me). The stove has worked better than any stove I have used in the past. While it is not as light as my alcohol stoves, it works far better in cold weather. In temperatures just below freezing it works as good, if not better, than my liquid gas stoves, is lighter, and far easier to operate. Hence my willingness to take it with me while snowshoeing. Something I would have never really considered before.

This stove has become a standard part of my cold weather and/or group gear. To summarize my findings, the stove is small and light, it is easy to operate and so far quite reliable. It works very well in warm and cold weather (though I have not been able to use it in temperatures much below freezing) and I noticed no change in how well it functioned when used at altitudes from 800’ to over 4k’. While it may be a bit large for solo trips it seems well suited for larger groups due to how quickly it heats water. It also simmers well despite the small diameter flame.

This is a great lightweight 3-4 season all weather stove, that I would highly recommend.

So I would like to thank the folks at 4AllOutdoors.org, North American Gear, LCC and Primus for the opportunity to review this fine product, and I look forward to many trips with it in the future.

Dave (the turtle) Wilkes

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