Twenty years ago, Primus released an innovative new stove on to the market. In the intervening years the Micron has undergone design changes, refinement and had features added. How is it holding up in 2023?
Those looking for a sub-100g canister top stove are pretty much spoiled for choice. We now have a slightly bewildering range from a number of manufacturers. It hasn’t always been this way. Primus has been one of the foremost designers and manufacturers, and their Primus Micron has long been a choice for lightweight campers and backpackers. However the Micron isn’t just one stove. Three Points of the Compass takes a glance at most of what has been available over the past twenty years.
The first Primus MicronStove, model P321383, was released in 2003. This minimalist stove had three bent pieces of stainless steel wire for pot supports and was also fitted with a built in piezo igniter. Made from aluminium and steel, the Micron weighed 94g. This made it one of the lightest canister top stoves on the market at the time. It was also one of the smallest- measuring 66mm x 42mm x 66mm. In fine conditions, preferably with a windscreen, this 2200W stove took around four minutes to bring a litre of water to a boil. The 7500 btu was modest compared to the Micron stove models that followed.
Early versions of the Primus Micron stove had a steel catalyst mesh centre to the burner head. Primus said this both protected the flame in windy conditions and helped distribute the flame across a broader area.
“Invented in Sweden, made in Europe”
Swedish manufacturer Primus had opened a manufacturing factory in Estonia in 1994 and much of their stove portfolio, including all of their Micron stoves were made at that facility.
Of note with this piezo gas stove is that the ignitor is a neatly designed affair, tightly aligned with the central gas stem, unlike the bolt on apparatus that succeeded it.
A second generation of the Micron stove, model P321393, was released in 2007. This introduced shaped pot supports of sheet metal with serrated top edges that supported and gripped pot bases better. The control valve of both first and second generation Microns was operated by a hard black plastic knob rather than the wire control that replaced it on later models.
The weight was later reduced slightly by removing the piezo on this stove as Primus were very aware that there was a ready and willing market of lightweight backpackers keen to reduce pack weight and eager for lighter stoves far removed from the cranky brass affairs of only a few years previous.
Also in 2007, the PrimusMicron Ti 2.5, model 321386, was released. This was a further development of the Micron stove and probably the pinnacle that the stove reached as regards low weight. This had weight shaved from their standard Micron model by swapping in some titanium parts. The non-piezo version weighed just 69g and delivered 2400 W 8500 BTU/h.
Things get a little complicated in the Micron history now as another stove model enters the scene. The Primus Express Stove was to become another important gas stove in their portfolio, frequently swapping in and out of fulfilling the role of small and lightweight canister top gas stove. The Primus Express stove differs primarily visually from the Micron by the valve control knob and how the support arms fold. The Express stove has pot supports that rotate around the stem of the stove, while the Micron has pot supports riveted to the burner that rotate up to lock in to place around the burner head. The Primus Express stove knocked out 2600W, 185g/h, more power than earlier versions of the Micron and less than later versions. There were a number of Express models introduced in 2008. There was the ExpressStove without Piezo, model P732484, and ExpressStove with Piezo, model P321483. A complete stove kit was also released, this was model P353083- Eta Express. This was an Express stove with Piezo, together with a one litre pot with heat exchanger, a small lid that also acted as a small frypan, and a windshield that hooked on to two of the pot supports. The Eta Express name changed to Express Stove Set in 2015.
The three Express models took the place of the basic Micron stove, though the Ti Micron remained available as a truly lightweight option. This was joined in 2008 by a titanium version fitted with an ‘Easy Trigger’ piezo ignitor. The MicronStove Ti, with Piezo, model P321389 weighed just 83g so was effectively a lighter version of the Express stove with piezo available at the time.
Note the two cast ‘wings’ protruding from the base of the valve section. These straddle the lindal valve on a canister and enabled a heavy pot weight to be supported while also reducing the chance of over-tightening on to the canister valve when screwing on. The same protuberances are also found on the Primus Micron gas lantern that I reviewed here. Later tweaks of the Micron design shifted these protuberances round ninety degrees and the feature simply became part of the valve block shape.
In 2010 Primus introduced blister packs for some of their lightweight stoves, the first of these was ExpressStove, model P321474, and ExpressStove with Piezo, model P321473. These were only available outside the European Union.
The MicronStove Ti model was discontinued in 2011, replaced that year by the ExpressStove Ti. This again featured titanium pot supports. There were two versions- the 86g ExpressStove Ti with Piezo, model P321486, and the 72g ExpressStove Ti without Piezo, model P321489. Sadly, some users reported quality issues with the titanium pot supports over the years.
As if this wasn’t confusing enough, in 2012 there were ten different item numbers for the Express stove in its various formats. Not for long, five years later, other than a solitary Express set that remained on sale, the Primus Express stove was discontinued in 2017. Or was it….
Following some design improvements, in 2017 Primus released an updated range of the Micron, now called the Micron Trail gas stove. In 2019 all Micron models were updated with new valves, and a fourth model joined the fold. Weights increased very slightly, ranging from 80g to 132g. 2017 and 2019 models of Micron stoves could each bring a litre of water to a boil in under three and a half minutes. If paired with one of their PrimeTech Pots, Primus said a minute could be knocked off this. Three Points of the Compass has one of the slightly lighter pre-2019 stoves, the Primus Micron Trail, with piezo and pressure regulator, model P321452, dating from 2017.
My 2017 Primus Micron Trai, model P321452, with piezo and pressure regulator, weighs 86g and knocks out 2600W / 8900 btu/hr. On full bore I can get 85 minutes out of a 230g gas canister, however I don’t run my stoves on full. It came with a decent enough 9.5g carry pouch. I have never used any of the pouches supplied with these stoves, preferring to wrap my stove inside a square of Lightload towel for storage inside my pot on trail, this is also used to wipe out and dry a pot after use.
Unlike the neat first versions of the Micron with piezo ignitor, this feature now looks very much a bolt-on accessory. The wire that sends the spark to the burner head, hopefully igniting the gas, is a temperamental nuisance. The little wire bends with impunity and frequently doesn’t spark. It needs to be positioned just right. Mine almost never works. This wire is also prone to snapping off.
Primus sell replacement piezos for these stoves (part no. 740700) and made a helpful instructional video on how to change it. In truth, it is a cheaper, better (and very slightly lighter) stove without it. Just simply carry a mini-Bic, handheld piezo, or as I prefer, a small ferro rod. You will need to carry one of these anyway, for when the piezo most certainly fails. As it was, Primus eventually abandoned the mounted piezo entirely. The Micron model that required release, but never was, is a Primus Micron with pressure regulator valve block and no piezo ignitor.
Other than the uncommonly seen blister packs, Micron stoves are usually purchased in a card box, that contains the stove, nylon carrying pouch, instructions, and the usual tag attached to the wire valve control.
The Micron is quite a noisy stove when on full bore and almost silent on low. It has a tall narrow flame and is more suited to narrow pots as heat is centrally directed on the base of the pot or pan. While it can be turned down very low and a simmer maintained, the smaller flame is extremely susceptible to being extinguished by even slight breezes
So, in 2019, there were four distinct versions of the stove.
- MicronTrail, without piezo ignition. Models P321450 (80g), from 2019 P321454 (87g). 2.2kW / 8600 btu. gas usage: 160g/hour.
- MicronTrail, with piezo ignition. Models P321451 (90g), from 2019 P321455. 2.6kW / 8600 btu, gas usage: 198g/hour.
- MicronTrail, with piezo ignition and pressure regulator. Updated in 2019 when weight increased to 94g. Model P321452. 2.6kW / 8600 btu. gas usage: 198g/hour.
- MicronTrail Duo. With canister adapter to fit EN714 lindal screw on valves and Easy Clic Plus canisters. Model P321456 (132g). 2.2kW / 8600 btu. gas usage: 160g/hour.
The fourth Micron stove was a model that few UK backers will have encountered. Though not the only manufacturer to do so, Primus introduced an innovative and interesting Duo feature to some of their stoves. The Duo connector enabled a stove to fit both the most common canister valve types found across the globe- canisters with screw on type EN417 lindal valves, and Easy Clic Plus canisters (more commonly called Easy Clic). This stove connector is of most potential use for someone travelling across Europe and uncertain what canister type they may be able to purchase.
The first Express Duo stoves were introduced in 2009. These were the ExpressStove Duo, model P321444, and ExpressStove with Piezo, model P321443. It was another decade before the first Duo version of the Micron stove appeared. Primus have informed me that the Duo version of the Micron was introduced in 2019, though my Primus MicronTrail Stove Duo was manufactured in 2018.
We now had the 82g MicronTrail Stove, model P321455, the 92g MicronTrail Stove with Piezo, model P321454, the 94g MicronTrail Stove with Piezo and pressure regulator, model P321452, and finally, the 132g MicronTrail Stove with Duo connector, model P321456. While the Duo version was advertised as weighing 132g, my example weighs 127g. As far as I am aware, this Duo version of the Micron is the smallest and lightest backpacking stove that ever incorporated this feature. This made/makes it a truly viable stove for the pan-european backpacker who likes having options. No Duo stoves were released with piezo and regulator valve block.
The valve block was completely redesigned and along with other small changes, most obviously to the wire valve control, the basic Primus Micron model became P321460. Alternatively you could buy it as Primus Micron Stove with Piezo, model P321461, the only difference being a remote piezo igniter included in the price.
The Micron Trail stoves’ stablemate was the PowerTrail, with piezo, model P324414. These were amongst the most powerful canister top stoves produced by Primus for backpackers and campers. A litre of water could be bought to the boil in three minutes, or two minutes with a PrimusTech Pot. However sales were not large and Primus decided to withdraw from this niche part of the market.
A pressure regulator version of the PowerTrail was released, model P324415. While this was a tad less powerful than the base model, the pressure regulator did ensure that it’s performance remained consistent almost regardless of altitude, run time and canister pressure. A Duo version was also available, this was model P324416 and lacked both piezo and regulator.
In 2021 the Micron Stove was again updated, the name simplified, the mounted piezo was removed from the design and the valve block and blending tube material changed. The wire valve control was also very slightly altered in design. The base stove was the 85g Micron stove without piezo, which now became model P321260. This stove was also available with a separate handheld piezo ignitor as model P321461. While this change to a remote ignitor was sensible as the slightly clunky piezo bolted to the side of the Micron stoves was not the best, there was no difference in the stoves themselves and I fail to see why two identical stoves had different model numbers. There was no pressure regulator version. Power output is 2600W / 8900 btu/h and in optimum conditions will raise a litre of water to a boil in three and a half minutes. This is still the official stove in the Primus lightweight category. However due to some unspecified production and sourcing issues, Primus have been unable to produce it, and replaced it with the Express stove in the catalogue for the past couple of years. So, in 2023, the Micron Stove is not currently available, nor is it officially discontinued. If you want the Duo version of the Micron, you will need to find one of the earlier models still sitting on a dealer’s shelves.
There have been some decent upgrades made to the Micron over the years. The wire valve control that replaced the former plastic knob is far easier and safer to both access and use in the confined space between a gas canister and hot pot above.
If you purchase an older Micron model with a piezo, this still has the appearance of a bolt-on afterthought, while also being pretty useless. Many other stove manufacturers have found ways to protect this feature and it is time Primus did the same. A basic model will cost around £30 mark, add a (useless) piezo and this increases to £40. Add the potentially useful pressure regulator and it is getting pricey at around the £60 mark. But shop around and you can get this stove a great deal cheaper. All versions of the stove are to the usual high quality Primus manufacturing standard.
“Ultralight and compact, the Micron Trail Stove is the stove of choice for weight-conscious backpackers”
Primus
In conclusion:
The Primus Micron was one of the best and most innovative of small stoves when first released. It was lightweight, compact and delivered decent performance at the time. Despite introducing piezo ignition and pressure regulators to the small canister top stove stable, it eventually got left behind as other manufacturers rose to the challenge. Most major stove manufacturers now have at least one sub-100g stove on their books. Stove design became ever smaller and cleverer and more compact, more powerful stoves are not difficult to find. Even pressure regulator valve blocks are not the uncommon feature they once were.
Piezo igniters have always been temperamental and the likes of Soto, Kovea, and MSR in Kovea’s OEM wake, have all found ways to make their piezo more reliable and protected. Primus could, and perhaps should, have gone that route, rather than just giving up on their mounted piezo and instead simply supplying a remote piezo ignitor.
Since the original wire supports were improved, the fold out pot supports on the Micron have universally been well made and strong, however many alternative backpacking stoves have been designed to make even smaller packages when collapsed and will stow inside the smallest of mugs or pots. While the Micron will also do that, you might struggle to fit in a gas canister with it.
The burner head design has barely altered over the decades and remains susceptible to side breezes. It would have been good to see the head being dished slightly, or given a raised lip around the circumference to offer a little more protection. The Micron never became a poor stove, just simply average. The Duo version however, still has something to offer those unsure on what type of gas canister they may be able to purchase.
Still on the Primus books is the Express canister top stove, as we have seen, another stove with a long history. The Express is now the simplest and lightest backpacking stove that Primus sell. However the Express doesn’t gain a great deal of attention from the lightweighters, despite weighing just 83g, 6g less than the much lauded 89g Primus Firestick Ti, which is the lighter version of their 102g Firestick.
Earlier this year I noticed that a couple of websites and reviewers, in their ‘best stoves for 2023‘, were placing either the old Primus Micron Trail or the Primus Micron in their top ten. However the Micron family of stoves do not currently appear on the Primus product pages and hasn’t for some time. You can still purchase one. The stoves have been available for so many years in their various guises that various models frequently turn up in decent used condition. In addition, many outdoor stockists are still sitting on new old stock, sometimes quite old old stock. If looking to buy one, be careful with what actual model of stove you are being offered.
Three Points of the Compass has previously looked at a few stoves that may suit the lightweight camper and backpacker. Links to these can be found here.
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