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Reviews > Cook and Food Storage Gear > Stoves > Primus AB ETA Solo Stove > Test Report by Ralph Ditton
Primus Eta Solo Stove
Test Report Series by Ralph Ditton
Initial Report: 5th August, 2010
Field Report: 3rd October, 2010
Long Term Report: 13th December, 2010
(courtesy of Primus)
My playgrounds are the Bibbulmun Track, the Coastal Plain Trail and Cape to Cape Track. I aim to become a sectional end-to-end walker of the Bibbulmun Track. I am nearly there as it is 964 km (603 mi) long. My pack weight including food and water tends to hover around 18 kg (40 lb) but I am trying to get lighter. My trips range from overnighters to six days duration.
Sighting the Eta Solo in its display case I was a little bit concerned as to where the burner unit was.
It was not until I took off the lid and discovered that the burner unit was tucked neatly on the inside of the pot together with a set of instructions.
When I assembled the unit it looked like what I expected from the web site. The only surprise was the heat reflector, pot support arms and the hanging hook assembly (suspension kit).
Bearing in mind that I had not looked at the web site since mid April and I had completely forgotten about them. A quick check on the web did mention them, but no photos of them.
All of the pieces fitted well together without any force needing to be applied apart from squeezing in the red buttons on the burner to allow the pot to sit and be locked into place when the red buttons are released.
The Eta Solo appears to be Primus first generation single personal cooking system that is compact, lightweight and miserly with fuel.
One thing that struck me immediately was the smell of the durable plastic lid that has a special opening for drinking hot brews. It smells very petrochemically. Not a good aroma to my nose.
The instructions come in a wide variety of languages such as English, French, German, Swedish, Finnish, Polish, Hungarian, Romanian, Czech, Bulgarian, Turkish, Arabic, Spanish, Portuguese, Chinese, Romanian, Danish, Norwegian, Dutch, and Italian.
When fully assembled for use using all pieces for the supplied pot, the Eta Solo (hereinafter known as stove) comprises of the following starting from the bottom, a) gas cartridge stand that can accommodate three different sizes of gas canisters. It can only take one at a time, b) the gas canister that has a screw type Lindal 7/16 valve, c) a burner unit with a built in Piezoelectric ignition system, d) a cooking 0.9 l (30.4 oz) cup/pot, e) removable wrap-around heat resistant cover with a sure-grip handle, f) plastic lid with a drinking hole and two draw air holes.
pot support stand
If I was not to use the supplied cup/pot I would use the following, a) as above, b) as above, c) the burner unit would have installed the three pot support arms and the heat reflector that would go around the burner and Piezo lighter, d) the other pot or pan.
pot supports and heat reflector in place
Should I use the suspension kit with the stove, I would do away with the cartridge support mentioned in (a).
No gas cartridge was supplied with the stove, however, the instructions mention that only Primus Propane/Butane/Isobutane mix cartridges are to be used exclusively.
I do plan to use other brands of gas canisters as I have done in the past when similar pronouncements have been made by a manufacturer and I will comment on their performance.
Why do I say this?
Butane and Propane are both non-polar and will happily mix together. The bonding energies of the molecules of both liquids do not really care. The resulting liquid will look like liquid Butane. (Acknowledgment to Roger Caffin FAQ).
So it does not matter what branded canister the liquid mix comes in. The main thing is that it is a screw type Lindal 7/16 valve so that it screws to the burner unit.
In addition, Primus gas cartridges are not that easy to locate for purchase. Very few stores here carry them. The only size that I have seen and purchased in the past is the 230 g (7.4 oz) cartridge. Apparently the 100 g (3.2 oz) cartridge will fit inside the cup/pot.
I have seen this size made by other manufacturers and the base is smaller than the cartridge that I usually use.
The 230 g (7.4 oz) cartridge will not fit inside the cup/pot.
The burner unit does fit inside the cup/pot. In addition, the gas cartridge stand will fit inside with the burner unit, but I have to spread one of the legs open to straddle the Piezo ignition housing. The support arms and suspension kit also fit happily inside the cup/pot.
The heat reflector would go inside the cup/pot first to sit on the bottom so that it is not in the way for the other items to stow away.
No mention is made as to what material the vessel is made out of, but a search on the web for their pots would indicate that it is made out of hard anodized aluminium as is the heat exchanger on the bottom.
There appears to be no non-stick surface on the inside, just plain anodized aluminium.
Stamped onto the sides of the vessel are on one side, two graduations with the top one stating 2 cups, so I presume the bottom is 1 cup as it appears to be equidistant to the other graduation.
On the other wall directly opposite the cup graduation are five graduations with the top one stating 0.5 L. It can therefore be said that the other equidistant graduations are at 0.1 L intervals.
From the 0.5 L mark to the top of the vessel there is a gap of 53 mm (2 .08 in) which would allow for 0.9 L to be contained.
I measured out water into the vessel and yes it does take 0.9 L but it is full to the brim.
That is overfilling it for cooking/heating purposes as the water would spill over when it is being warmed up to boiling point.
On the outside 20 mm (0.78 in) from the top is the bracket for the suspension kit. It appears to be heat stamped to the side as the means of attachment.
Wrapping around the vessel is a removable heat resistant cover that has a handle called a "sure-grip". It is just a piece of webbing stitched to the cover down the side and forms a loop so that the back of my hand fits snugly inside whilst my palm and fingers wrap around the vessel.
The cover has a U shape piece taken out of it on the top section so that the bracket for the suspension kit is accessible.
The burner component clips onto the vessel by pressing the two red tabs in. When released, they lock into place the vessel which has a flange turned inwards. On the metal strips attached to the red tabs is an angle which lock into the flange.
The flame control knob has a - and + symbol stamped into the end to indicate high and low flame control.
Opposite the control knob is the Piezo ignition square button. It is just a matter of pushing it in to obtain a spark to ignite the gas when the control knob is turned on. It is then just a matter of adjusting the flame with the knob.
The knob turns anti clockwise to release the gas.
There is a metal warning label attached to the control knob by way of a key ring. It tends to get in the way. It warns about Carbon Monoxide, using only outside and not to use by connecting to a remote gas supply.
The actual burner is quite small. It is only 33 mm (1.3 in) in diameter.
Trying it out
I filled the vessel to the 0.5 L mark with water from the tap which had a temperature of 16 C (61 F). The outside air temperature was 13.3 C (56 F) as measured by my Kestrel unit. There was no wind. The altitude was 7 metres (23 ft).
It took the stove 5 mins 20 sec to get to a rolling boil with the control knob in the normal position to give a flame that covered the inside of the heat exchanger but not roaring on full throttle.
I lit the stove with the vessel attached and got a brief flare out of flame right around the air intake slots as I ignited the gas. It lit on the very first push of the Piezo button.
Fortunately I had long sleeves on or I would have had singed hairs on my wrist on the hand that I used to light the unit.
If this is going to be an ongoing problem, then I will be lighting the burner first then attaching the vessel to the burner to avoid the flare out.
When removing the vessel from the burner, I had to be careful in not touching any metal parts as they were still very hot. I found it a little bit tricky trying to squeeze the red buttons in without my fingers slightly touching the metal especially the bottom of the ring directly above the red buttons.
The heat resistant cover worked but I could still feel heat coming through it. It was not hot enough to worry me but I was definitely aware of it.
The petrochemical smell from the lid was pronounced when the water was getting close to boiling.
Things I like
I took the Primus Eta Solo Stove out for its first cookout to Prickly Bark on the Coastal Plain Trail. The campsite sits at an elevation of 80 metres (263 ft) which is in reality a very large sand dune covered in Banksia trees and scrubby, prickly vegetation.
Temperatures in the evening and morning when I was using the unit was around 6 C and 9 C (43 F and 48 F) respectively.
Because I had been fiddling with all of the components of the stove by taking the cup off the burner unit and the heat resistant cover just to look at it all again, I made the mistake of putting the heat resistant cover on upside down.
I was not aware of this when I lit up the stove to cook a carrot and bean combination to go with the evening meal.
After a short time the flame went out and I couldn't work out why straight away. The gas bottle was full and it was not freezing so the gas should burn.
Then it dawned on me. I could only see into the burner section through the inverted U shape. Hang on, that was supposed to be on the top just under the bracket for the suspension kit.
The heat resistant cover was below the bracket and this caused the bottom section of the cover to block off the air vents apart from where the U shape was.
I had starved the flame of air.
Once I realized this I removed it completely and lit up the stove again.
This time I got another flare out of flame through the air vents and the flame singed the hairs on the back of my right hand.
On each and every occasion that I lit up the stove, I got a flame flare out apart from when I had the air vents covered by the cover.
The stove was lit to cook and/or boil water eight times between the evening meal and just after breakfast when I made a pot of tea to wash breakfast down.
In the morning, I did replace the heat resistant cover, the correct way up and noticed that it slid down over the air vents.
I had to undo the hook and loop and pull on one edge whilst holding the cover near the other edge to ensure a snug wrap around the vessel so that it would not slip down back over the air vent.
One thing I noticed that would be of great assistance would be to have a small extrusion to the lid so that I could use it as a finger grip to remove the cap from a very hot vessel and avoid the steam.
I needed to remove the lid to pour the water into cups and remove cooked vegetables.
When the stove is attached to the gas canister with water up to the 0.5 L mark, it is not plum bob perpendicular. The vessel takes on a slight lean.
The reason for this is because there is a bit of play between the control knob housing and the moulded bracket that holds it and the Piezo igniter. In addition, there is also play at the top just under the burner head where the stem passes through the bracket that has the two red buttons that release the burner unit from the vessel.
out of kilter
As far as I can tell, this has had no negative affect on the performance. I just looks out of plumb.
Another thing I need to be cognizant of is not to over fill the vessel with water. I filled the pot to within 20 mm (0.8 in) of the top and when the water boiled vigorously, it literally spat out through the two holes in the lid a good 100 mm (4 in).
As an aside. The water did boil very quickly. Within a few minutes.
Over the long weekend in September I went on a car based camp that was for three days and two nights at Gelcoat within the Wellington National Park.
The camp sat at an elevation of 80 metres (263 ft) and 40 metres (131 ft) from the Collie River.
Temperatures ranged from a high of 26 C (79 F) to an evening low when cooking dinner of 8 C (46 F).
The gas canister had a mixture of 70 º Butane and 30 º Propane and was half full.
Cool evening and early morning temperatures had no effect on the efficiency of the burner unit. It operated very well.
One lady in the group was having a good look at the stove and pulled the heat resistant cover off. She then reassembled it and screwed it back onto the gas canister.
What she did and I failed to notice when I went to fire it up shortly afterwards was that she had put the cover on upside down. This caused the cover to cover over the air vents of the stove.
The lady had covered the vents completely unlike my effort earlier in the test.
I couldn't work out why the flame went out straight away when I lit it. I tried a few times to relight the stove and my thoughts were not very complimentary during this process.
I even unscrewed the gas canister off to see if I had run out of gas then I noticed the cover covering the air vents. The penny dropped.
After righting the heat resistant cover and reassembling the gas canister to the stove, it lit up and did its job. I also righted a wrong. I took back what I said about the stove not working.
I still experienced flare out of flames but not on every occasion.
The difference between getting my hairs on my hand singed or not was about one and a half extra seconds of gas being released from when I turned the control valve on and pressing the Piezo ignition button.
If I was not quick enough I got a flare out.
The other issue that I have is after boiling water or cooking my eggs and/or vegetables, I am still getting a tickled up top part of my thumb and middle finger when I squeeze the red buttons in to release the pot from the stove. The skin on my digits are touching the underside of the metal ring immediately above the red buttons.
If I try and squeeze the red buttons in with my digits further down and away from the metal, I find it very difficult to press the buttons in to release the stove from the pot because I am closer to the pivot point.
What did I Cook?
On this trip I cooked chopped up vegetables for both of my evening meals. It was a simple process of bringing the water to the boil with the vegetables, let them simmer for about a minute and then turn the stove off letting the vegetables cook "Dutch Oven" style.
This method entails putting the lid on the vessel and blocking the holes on the lid to keep the steam in.
Whilst the vegetables were cooking by the "Dutch Oven" method I was then able then to attend to the other components of my meals.
For breakfast on the first morning I poached an egg.
It was not a total success because the action of the boiling water sunk my poached egg boat. The egg did cook whilst submerged. I just had a bit of trouble fishing it out of the bottom of the pot then draining the water off it.
The photo below shows the egg just moments before it sank.
The following morning I did a boiled egg to have as my morning tea on the planned day walk.
Again I brought the water to a rolling boil with the egg in the bottom of the vessel. Very quickly upon reaching the rolling boil I turned the heat off for three reasons:
1) I did not want the egg shell getting cracked from the rolling boil action of the water.
2) To complete the cooking action by the "Dutch Oven" method.
3) To conserve my gas.
The boiled egg turned out, to use an Italian expression,"Perfecto". Slightly soft in the yoke.
The photo below shows the stove heating up the vegetables on the first night.
heating up the vegetables
The petrochemical smell emanating from the lid appears to have gone. I cannot smell it anymore.
Things I like
Things I dislike
I only had the opportunity to do an overnighter during this test phase at my usual haunt of Prickly Bark on the Coastal Plain Trail.
The reason for this is the fire restrictions of any type of flame placed on my testing areas due to the fire warnings of "catastrophic".
We have had the driest and hottest November on record with an official heat wave of temperatures exceeding 35 C (95 F).
The hottest day was 39 C (102 F).
Temperatures at Prickly Bark over the two days averaged 33 C (91 F) with a hot Easterly wind blowing in from the desert and central wheat belt.
I only boiled water to use for my dehydrated evening meal and for cups of tea at my supper time and breakfast.
Altogether, I had four firings of the stove.
I had no issues with placing the heat resistant cover on upside down as I left it on and did not fool around with it.
To experiment with the stove, I used another pot which required me to use the three pot supports and heat reflector.
The pot used was an Antigravity Gear non-stick 3 cup pot with lid. I had to use a spondonical (billy grips) to remove the hot pot from the stove.
This was for my final cup of tea.
Setting up the stove to use another style of pot was very easy. The three pot supports slipped easily into their respective holes and cut outs on the side.
The heat reflector then sat on the elbows of the pot supports level with the burner head.
When I placed the pot on the pot support arms it became very obvious that there was a tilting of the burner unit. I mentioned this in the Field Report using the supplied vessel.
With the burner unit screwed onto the gas canister and supporting the pot of water I estimate that there is a lean of 5 degrees below the horizontal on one side and an uplift of 5 degrees on the other side above the horizontal.
I was worried that the pot might slide off with hot to boiling water. Fortunately that did not happen.
The lean is caused by the bit of play between the control knob housing and the moulded bracket. One of the legs on the burner was just about touching the gas canister. The gap, by my measurement back at home was about 1 mm (0.04 in).
I do like the versatility of using the supplied vessel and using other pots. This gives a better option to cook different types of food.
With a bigger, broader pot I can cook vegetables and eggs for more than one person at a time.
Also with using a different pot with the set up of pot supports, I did not experience any flare ups of flames, unlike when I used the supplied vessel which was covered in the Field Report.
The petrochemical smell did not reappear during this phase, so hopefully it has gone for good.
Thank you to Primus for making this stove available to test.
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