Hello, so I got this one: https://classiccampstoves.com/posts/37173 I love the Vesta single burner stove, compact, no moving parts that you can lost, powerful and very very sturdy. I had the opportunity to get a dual burner for less that what you usually found a single burner on the french ebay site. And I got it. Pretty amazed to found it came with little funnel, meths tin and a multipurpose wrench. Nice! My personal review: It is a very well made stove, very compact and sturdy as the single burner one. Case is made of a pretty thick gauge tin with a lot of folded edges here and there to avoid sharp edges, it has spot welds. The hinge pin is a pretty think rod (maybe 2mm in diameter) which makes it an indestructible hinge... The tank is permanently outside the case, which at first sight, looks quite weird, it is made of iron, basically like a plumbing pipe with two caps welded, one at each end. Fuel cap at the center, made of brass with the NRV integrated. Both burners are same size, and also same size of the little single burner. Each burner connects directly to the tank and have a large cup under the burner for the preheating fuel. It has the typical mesh from the Vesta stoves to help to keep the absorbent material from falling (very useful in my opinion). Grille is also heavy duty, made of iron rods and think bent iron plates, making to X over each burner. Being a dual burner stove, for sure you were going to expect some pump, huh? The answer is no, so it is a self pressure stove. The size of the preheating cups under the burners makes you think the lighting process it's not going to be easy... An that's true. The trick to open a little bit the regulating key and let a little fuel to come out is nearly impossible. The thick, big and cold ironish tank make your hands be like nothing if you want to heat the tank a a little bit before preheating. I filled gently the cup with meths, after it burned out all the meths the burner didn't started, so I repeated the process. At the second time I was luck to get a weak blue flame that started to heat stronger after maybe two minutes. The tank was just midl then. Then I started the left burner and It wasn't easier than with the right one. Each burner is a lot weaker than my single burner Vesta. The grille just above each burner is the effective area to cook, as the lid, even laying horizontal, is higher than the grille. That makes impossible to put large pans or pots (centered) on that stove. Another cons is that the regulating knobs are so close that even being made of Bakelite they get very hot, so you burn your fingers... So it is a stunning and rare stove, which turns to be a not very handy one... Enjoy!
Variation between the burners suggests at least one of the burner wicks is in bad shape and I'll bet the other one isn't much better. It's not a fair review of the stove if you don't strip the burners, replace the wicks and then see how it fires up. All you're telling us is that it's in poor condition - operationally speaking - as purchased. With wicks replaced and burners stripped and cleaned (crucially the small bore port between the head of the wick tube and the jet housing that gasoline stoves have) it would be great to hear you report back. If performance is still bad? From what I can see of the fuel cap in one of the photos in your Stove Reference Gallery entry for this it's the same as the cap on a single burner version and has no provision for an external hand pump, such as that for a Coleman Quick Light lantern or Optimus 8R with a mini-pump. Would an Optimus mini-pump cap fit? I'd be looking to pressurising the tank with a separate pump rather than warming up the fuel tank with a heat source. Pouring hot water over it is self-defeating if you're looking to use the stove for heating water! Anything hotter's a fire risk! Interesting stove. John
Thanks for sharing your Vesta two burner. I've got several one burner Vestas and like them very much for the same reasons you do. The size of the tank and the fact that it's shielded from the flame by sheet metal probably accounts for the reduced heat output. There is no such barrier between the flame and the tank of the single burners so the tank heats up and pressurizes quickly. I'd imagine that two burner tank would take forever to heat up especially with only one burner going. Replacing the wicks as Presscall suggests would probably be helpful. The originals are cotton and scorch over time inhibiting the flow of fuel. I replace those in my stoves with fiberglass wicks and it made a huge difference. Great stove even if it is French and doesn't work well, I'd love to find one myself. Again, thanks for taking the time and trouble to share it with us.
I don't believe the heat of the flame impinging on the fuel tank in a gasoline self-pressurising stove is influential in pressurising the fuel. Most stoves have a heat shield to reflect most of the heat from the flame and pot base away from the tank. Logic suggests the fuel burning in the priming pan has to be capable of pressurising the fuel before the burner is even in action. Pressurisation is done by heat conducted from burner to tank by the connecting tube and by the fuel in the tube - which is after all getting hot enough to be vapourised towards the burner end of the tube. Consequently, the metal the fuel tank is made of and its heat conductivity, or for that matter if the wall of the stove box separates tank from burner is irrelevant. I've been using a German Pressgas gasoline stove a lot lately and that has a steel fuel tank well shielded from the burner flame. Even before I've pressurised the fuel with the pump or lit the priming fuel, the vapor pressure of the fuel sitting in the tank on a cold day in Britain is sufficient to prompt a dribble of fuel at the jet if I open the control valve. Difficulty in priming the Vesta and poor performance when it eventually gets going is what you've described. It's not a design fault but a clear symptom of wicks in poor shape and burners clogged with charred wick. With wicks replaced and burners cleaned out it'll go like a rocket I'm sure.
If you're correct, then the single burner Vesta is the exception that proves the rule. The Vesta flame is so close to the unshielded fuel tank that radiated and reflected heat do in fact play a significant roll in pressurizing the tank. I know this from running a test to determine BTU output over time. Actually I ran three tests. The first without a pot, the second with a 6 inch diameter pot filled with water, and the third with a 10 inch pot filled to the same height with water. The tests were run using the same VESTA stove fitted with an aftermarket silent cap under identical conditions. Each test was run for an hour with the stove being weighed every 5 minutes. From the stove weights I calculated the BTU/hr output over each 5 minute period. The results are shown on the line graph below: I did this testing several months ago for my own edification. I thought of posting the results on CCS but decided no one would be interested since I seem to be the only person who regularly uses VESTA stoves. Anyway, a big pot radiates and reflects more heat to the tank and increases tank pressure more than a small pot which in turn increasing pressure more than no pot. Incidentally, the BTU/hr. output seemed awfully high to me so I measured the size of the jet and found that the hole had been worn from the normal .23 mm to .25 mm. With the enlarged jet this stove really screams. I'm still using this jet not only because it boils coffee water quickly but also because when the cleaning needle is up inside the jet enough gas escapes around the needle to provide a perfect simmer for cooking rice. I wish I'd taken a photo of the flame when it was putting out 9,000 BTU's. It was about a foot high and really quite impressive!
Thanks a lot for your comments! As you said, the stove was fired, nearly 'as found' with just an exterior cleaning and a cap seal and new NRV. The hurry to fire the stove to see it running made me end with that partial job... I'll replace both wicks too see how it then performs. IMHO I think that heat from flame does affects to get pressure, especially on thin tin or brass tanks. Heat shields are there to avoid overheating to avoid overpressure, right? BTW: z1ulike, what do you mean by a wick made of cotton and SCORCH? Cheers!
Interesting graph Ben. The output peaks and then tails off, presumably because the fuel's being used up and with less volume of fuel in the tank the vapour pressure decreases and hence heat output goes down to the point where the flame goes out when it runs out of fuel. The point I was making was that one of these stoves is surely not designed to rely on radiant heat from the flame to get it up to pressure when priming it or maintaining it at pressure in use. A foot-high flame as a result of reflecting heat onto the tank from a too-large pot may be impressive but it's not a lot of use, practically speaking, for cooking on. More modest tank pressures are intended and are achieved with the conducted heat (as opposed to radiant heat) from the burner. Regarding the wick, there's a surface scorching or browning of it which is normal and there's burning to the extent that it breaks up and hinders fuel and gas flow. The main cause of burning a cotton wick, xavi, is letting the tank run dry. As long as fuel's passing through the wick it's kept from burning as a wick in a paraffin lamp is. It's usually the irreversible damage of a burn-out that kills wicks off. John
Using the stove with the valve wide open as was done in the test is only useful for melting snow or boiling water for coffee or pasta. Used this way the stove is actually self regulating as you can see from the graph. The flame and heat output automatically adjust to the size of the pan. The larger the pot the greater the heat output. In practice the stove works quite well for this purpose. Put a too-large pot of water to boil on a Vesta and it quickly ramps up to handle the size of the job without any pumping or user intervention. I've done a lot of cooking on my Vesta's from pancakes to rice. The downside to this stove is that it has to constantly be watched and adjusted when cooking foods that might scorch or burn. As the pan heats up it reflects ever greater heat back to the tank gradually increasing the flame under the pan as the food cooks. Frying bacon is the opposite of boiling water. The stove works automatically when boiling water but requires constant attention when frying bacon. You have to keep throttling the flame back as the pressure in the tank increases or you end up with burnt bacon or at worst a grease fire. Cook breakfast on three separate Vesta's and you've really got your hands full between constantly monitoring and adjusting the flames, turning bacon, flipping pancakes, and cracking eggs. It's the opposite of Dutch oven cooking where you can walk away and enjoy a martini as dinner cooks.
There is a cotton wick inside each burner which draws fuel from the bottom of the tank. The wicks have a metal rod inside to hold their curved shape. The end of the wicks closest to the burner can scorch and inhibit the flow of fuel. I think Presscall is right that this is primarily caused by letting the fuel tank run dry while the stove is operating. It might also be cause by unwittingly priming the stove when the tank is empty and the wick is dry. Here are 4 wicks taken from single burner Vestas. The top wick is in pretty good shape with just minor scorching just at the end. The second is a little worse. The third is extremely scorched and hard. The fourth is darkened by rust which could potentially reduce fuel flow as well. The pipe connecting the burner to the tank is made of steel which is often rusted inside of poorly maintained stoves. On my Vestas I replace these cotton wicks with fiberglass wicks into which I inserted a piece of stainless steel wire to keep their shape. The fiberglass wicks work well and won't scorch even if the tank runs dry. However replacing wicks is a lot of trouble and I wouldn't bother unless you plan on using your Vesta regularly. If you do decide to change the wicks let me know and I'll give you a few tips.
Try pre-heating your burners a couple of times They are quite a large burner, 8ozs, and overall approx 5 inches long
Ben, This may be a good place to add your tips because some time later someone will search this forum and find this thread. Ken in NC
O.K. one last thing then I'll shut up (one should never get me started on the subject of Vestas!). I think you are right xavi. Most self pressuring stoves with thin tanks are designed to be pressurized only by the conduction of heat through the fuel pipe. Hence the shields on Optimus 8Rs, the tank on the outside of the box on a Campus 5B, the burner above the tank on SVEA 123s etc. These precautions limit the pressure inside the tank which in turn moderates the flame. However it seems the single burner Vesta is uniquely designed to rely on radiant heat from the flame to get it up to pressure when priming or maintaining it at pressure in use. Hence the thick steel tank located inside the case in close proximity to the flame with no heat shield. It also comes equipped with a safety relief valve that is so stiff it doesn't activate even when putting out 9,000 BTU's with a pot of boiling water overhanging the tank. The two burner Vesta with a steel pipe connecting the burner to a large tank made of thick of steel (poor conductor of heat)and shielded from the flame by the case may well be contributing to the weak flame you're experiencing. With such a configuration it might take a long time to heat up and pressurize the tank making it behave more like a conventional self-pressuring stove only weaker. This lack of oompf may have limited the appeal of these two burners and led their scarcity. Still...I WANT ONE!
O.K. just one more thing, then I'll shut up. This photo shows what I used. The wick is a 1/4 inch fiberglass core braided rope having a twisted fiberglass core sheathed in a blended KEVLAR(R) and fiberglass braid. I purchased online here http://tinyurl.com/pmdqyfg . The wire is 10 gauge stainless steel bent at the end so it won't push past the end of the wick. Any wire will work as long as it's stiff enough to hold its shape. The thread is simple cotton sewing thread. Fiberglass wicks don't hold together as well as the cotton ones so I wrapped them with cotton thread to keep them from fraying and to hold their shape during installation. Once wrapped, it's fairly easy to push the stainless wire down the middle of the wick and bend it into shape. The key to this operation is a piece of plastic drinking straw cut lengthwise down the middle. Place both halves of the straw around the wick letting it extend 1/8 inch past the end. After much trial and error I found that leaving a small gap between the end of the wick and the brass insert it butts up against works best. If you shove the wick all the way in it blocks the hole and limits the flow. Using the straw allows you to compress the wick to a diameter that fits in the hole. The stiffness and smoothness of the straw allows you to easily slide the wick into the burner tube. When inserting the wick hold the straw tightly so the wick doesn't slide and push it in until the straw butts up against the brass insert inside. Holding the wick firmly against one half of the straw, bend the other half up and pull it out with your other hand. You can then hold the wick in place against the side of the tube and pull the other half of the straw out. Once both straw halves are removed the wick will expand and hold firmly in place. You can then insert the wick into the tank and tighten things up.
Interesting weighing exercise Ben. Your graph implies that there might be a performance "sweet spot" for self pressurizing stoves... Related to tank fuel level... Or tank temperature... Or both... Or something else... Hmmmm. You controlled for the loss of weight of water evaporating from your pot, right? So if xavi's stove is running cold, how about running a heat conductor from some warmish point on the burners around/under/in contact with the fuel tank. Has anyone tried a heating element like this?
No, the pot was briefly removed every 5 minutes so the stove could be weighed by itself. Then the pot was replaced until the next weighing.
