The Triad XE stove in operation, with priming cap.
The Vargo Triad XE is a jetted and pressurised alcohol stove that looks superficially a bit like its sibling, the Triad, but there are a number of significant differences. It is promoted as being 'dual-fuel': you can use the assembly to burn solid fuel tablets as well by removing the alcohol tank. This review will focus on using the Triad XE with alcohol, and a small modification I made to the stove.
The Vargo XE is light, robustly constructed of titanium, and it has really strong legs and pot supports. However, getting it going proved very difficult at first, and the stove usually just went out with fuel remaining. Basically, there's a lack of thermal feedback without a very close-fitting windscreen.
The reasons for the poor performance suggested that a small modification might make the stove far more tractable. I tested the modified stove and the result was wonderful: the modified stove works with or without a windscreen, and it burns far hotter than before. Best of all, the modifications are easily made.
What's Good - as bought
- Robust construction
- Stable on the ground
- Strong - handles a heavy pot
- Easy to set up
What's Not So Good
- VERY hard to get going
- Can go out
- Needs a very close windshield to get going properly
What's Good - after modifications
- Strong, stable and robust still
- Burns much hotter
- Can operate without a windshield in still air
|2006 Triad XE|
|Stamped, spot-welded and riveted|
|'Pill can' with holes around the top, in a small support base with legs and pot supports|
|12, drilled around rim of lid|
|Not stated, but a shade over 1 fl oz (28 mL) of denatured alcohol|
|Claimed: 6 minutes for 2 cups|
|Claimed: 9 minutes when filled (packaging) or 25 minutes (web site)|
|"One weight-conscious backpacker," boiling water and light cooking|
|Measured: 1.73 oz (49 g) total, claimed 1.5 oz (42.5 g)|
The Triad XE looks a bit like the Triad at first, but there are several differences.
- The XE design has separated the support structure from the fuel tank/burner.
- The XE fuel tank has a lid, so filling and emptying it is much easier.
- The XE is pressurised.
- The XE is heavier (but it's still very light).
- The flames on the Triad go upwards; the flames on the XE go outwards.
Before we get into the operation of the stove, I should mention that the design makes the stove very stable. The fold-out legs can be dug into the soil a bit, after which the stove doesn't move. The fold-out pot supports are just as rugged. I can confirm that the stove will support many pints (or litres) of water without a worry. However, if your pot/cup has a base smaller than 3.6 inches (92 mm) diameter, it does not sit on the pot supports very well unless you fold the pot supports inwards, to rest on the fuel tank. The support circle is then rather small. This is a stove for wide pots.
The tips of the legs and pot supports are quite sharp and could damage other gear if not folded away carefully. I did worry a bit that the tips would gouge my aluminium pots. Of course, a titanium pot or cup would have no trouble. If this really worries you, it is fairly easy to smooth the tips down a bit with a grinder or small sharpening stone.
Field Experience - Part 1
I spent some time with this stove, but I could not get it to burn well. Time and again the flames went out while there was still some alcohol inside the tank. Obviously I was doing something seriously wrong. I sat down and had a careful look at how this stoves works, and came to the conclusion that the support base was actually cooling the fuel tank down by channeling air against it. This is illustrated in the photo here, where the green lines show airflow being sucked in through the holes by the flames to hit the side of the tank. If this incoming air is cool, it will cool the tank and stop the alcohol from boiling.
The Triad XE stove with green lines showing cooling air flow.
Subsequent discussion with the designer, Brian Vargo, revealed that I should be using a very tight windshield (as with the Triad). While the XE packaging does not mention the use of a windshield, the web site states: "NOTE: A special windscreen is required! The windscreen will maintain the intensity and efficiency of the flame." The windshield will cause the air around the support to be heated by the flames so the tank won't be cooled down.
However, it seemed to me that there should be another ways to make this pressurised stove burn well, so I decided to see if my ideas would work. This means that the rest of this review concerns a modified Triad XE. However, the modifications are simple.
The alcohol has to be boiling to be forced out the holes in the lid, to make flames. This means the fuel tank has to be heated. The flames coming out of the standard holes all point away from the tank, so they won't do this. Could I add a couple of flames which would heat the tank? Certainly this would be possible if I could get them pointing downwards from the lid rather than outwards.
Modifications to the Triad XE.
When the lid of the fuel tank is pressed on properly it comes down to the pink line in the picture above. I marked this line, and drilled four small 0.7 millimetre diameter holes at 90 degree intervals around the wall just above the line. The red arrow points to one of them. This was easy to do with a sharp new drill bit. These holes would make four more jets of flame, except that they would be largely blocked when the lid is pressed down. So then I lightly tweaked the rim of the lid away from the hole at each hole. The tweak is visible at the two blue arrows, with the lid slightly rotated out of position. This tweak makes a gap over the new hole, and this gap lets the alcohol vapour come out, but the jet is deflected downwards. The deflection is most obvious when you look at the right hand blue arrow. When the alcohol vapour burns there will be a flame going down the side of the stove for a little way before it curls back upwards toward the pot on top of the stove. This flame (all four of them actually) will heat the side walls of the fuel tank.
The four tweaks to the lid were done with some round-nosed pliers, and are pointed to by the red lines in the photo below. There is one tweak to each hole I drilled. The exact shape of the tweaks isn't critical as long as the alcohol vapour can come out. Equally, I found that the tweaks don't need to be very large: what is shown is probably more than is needed. Only a very small gap is needed, so don't overdo it.
Tweaks to the rim of the lid to deflect gas flow.
With the extra flames going down the side of the fuel tank for a little way the tank will be heated. The flames will soon turn around and go upwards because they are trapped inside the support base. There may be a very small loss of fuel efficiency, but I haven't been able to measure it with any reliability.
Field Experience - Part 2
Does the modification work? It certainly does. A little bit of priming fuel in the support bowl plus some under the support (in the green cap shown in the first picture) is enough to get the stove started, and once the flames start coming out from the new holes the stove is up and running. In fact, too much alcohol can make the stove roar a bit too much at the start. Priming now requires a delicate touch rather than a big slosh. The flames now coming out from the main jets are at least 1 inch (25 mm) long.
In fact, the first test run was perhaps a shade too successful, so I flattened the tweaks down a bit to restrict the flow out of the new holes. I found that not much flame was needed from those new holes to make the stove go just nicely. It is quite possible that only two new holes would suffice, but it was a bit hard to test that when I already had four holes.
It is hard to see alcohol flames in the daylight of course, but the next photo shows them coming out: there is an orange glow at the right hand side and a faint trace of blue at the left. There is a windshield in this photo, but it is more for convention and priming than for real need. The stove will now run quite happily with no windshield at all, as shown in the first photo at the top.
This photo shows a small green aluminium bottle cap under the stove. I use this for priming both the XE and the Triad. The use of the cap lets me monitor how much alcohol I use for the priming, and I found that I really needed only a millimetre or two of alcohol in the cap, plus slightly less in the support bowl. Too much priming is to be avoided. As soon as the alcohol in the cap is lit I poke it under the stove, where it makes a nice controlled flame which burns for between 3 and 4 minutes. The fuel in the support bowl is lit by the flame from underneath, especially if I put the little cap at one edge rather than right under the middle of the stove.
Field Experience - Part 3
The Vargo Triad has jets pointing upwards, while the Triad XE has flames pointing outwards. I found I needed to use a fairly wide pot with the XE to take advantage of the flame spread. This is especially so now the stove burns more strongly. Typically I use my 150 millimetre (5.9 in) diameter Trangia kettle. If you don't want the flames spreading out so much, you should have only two small extra holes under the lid, to apply less heating to the tank.
Boil time depends on a lot of things, but there was no question about whether the modified stove could bring 2 cups of water to the boil. It did so very reliably, and much faster than the Triad. With the windshield shown in the pictures set about 1 inch (25 mm) out from a Trangia kettle, priming to a good flame took about 20 seconds, and then the boil time for two cups of water (500 mL) was about 5 minutes 20 seconds after that, from 20 C (68 F).
Filling the container up with 1 fluid ounce of alcohol, which is the maximum amount of alcohol it can reasonably take, gave a burn time of about 7 minutes after I had done my modifications. If you run the stove without the modifications the burn time will be longer, but so will the time to boil. A definite time cannot be given since the burn rate depends so much on the amount of thermal feedback provided.
- Putting fuel in the stove tank is very easy (especially compared with the Triad).
- The packaging claims that the burn time is 9 minutes, while the web site claims 25 minutes. The 9 minutes seems about right for the modified stove.
- Dual fuel operation: tip the stove upside down and burn solid fuel tablets on it. Not tested.
- Recovery of unused alcohol is easy once the stove has cooled down, provided you haven't pushed the lid on too tightly.
Morning tea with the Vargo Triad XE.
The Vargo Triad XE is a very sturdy combined alcohol and solid fuel burner.
Recommendations for Improvement
- I'd like to see the modifications I discussed offered on the stock stove. I have discussed these modifications with Brian Vargo and at present he does not wish to adopt them as he is happy with the stove as he uses it. This is fair enough.
- You should use metal layer under the stove for safety; a windshield is a very good idea anyhow, and the small priming pot is very useful.