This is only a ‘first test’, and I may find I like it OK on further use, but…
I bought one of these for under $40, shipping included. At that price you don’t expect too much. The alternative, that I’ll likely get eventually, maybe in a year or two, is much heavier, harder to ship, has insulated glass doors, etc. etc. Oh, and costs two or three times as much…
So I figured it was ‘worth a shot’ to try this. (And it likely was ‘worth it’, where ‘it’ is not much money…)
OK, the product is reasonably designed and built. Folds up small and easily for transport. Whole thing is about the size of an old large laptop from a decade or two back… Set up is easy (two built in latches top and bottom hold it locked open / closed and the sides, top, and bottom have little tabs and slots that engage.)
Some folks reviews had said the temp gauge was way off. I put a calibrated oven thermometer in mine to compare. (Calibrated in my electronic controlled GE electric oven that cooks perfectly…) It was not an exact match, be very much ‘close enough’. I’d put it at about 15 F most of the time. But that “most of the time” is the key…
The Test Rig
I set up the oven, empty, on my Coleman 2 burner “Dual Fuel” camp stove. This stove has been the primary “Disaster Prep Stove” for us for the last 1/4 century or so. Not used much in that time, it mostly lives in a box in the garage “for Quake Day”. I have used it at initial buy (to make sure it worked) and at least once a year or so as a ‘prep check’. A couple of times on ‘car camping’ events with groups; and, as of last year, set up in the Patio Kitchen ‘work in progress’. It has been a nice way to make tea and coffee during warmer weather while “working” on the patio, without need to track yard debris (i.e. ‘wipe your dirty feet!’) into the house. I decided to do this once I figured it was time to convert the ‘disaster prep’ from “unleaded gasoline” over to kerosene and from “4 folks, neighbors and friends” sized down to “2 folks & stragglers”.
I’ve decided to go to kerosene so that I don’t have to keep doing “fuel rotation” on unleaded gasoline. Gasoline doesn’t store nearly as well, and I’d dump a large can of it into the ‘gas car’ each August and refill. (Summer gas evaporates less…) Kerosene in metal cans in relative cool and dark will keep for years. Also, given the rare actual usage, even after a 7.x quake, I’m just not as concerned about Kerosene having a ‘bit of smell’ in use. Also, the Government is still playing with “what is gasoline?” and we’ve gone through a variety of ‘odd things’ including MTBE and now Ethanol at 10% perhaps headed to 15%. The stove was never designed for that, so who knows how well it will work. All in all, time to ‘move on’, so I’m going to “use the stove” more and “save the stove for ‘that day'” much less.
This stove is the ‘design point’ for the oven, near as I can tell, as Coleman describes how to use it on just this kid of stove. So it seems like the best test rig. The stove puts out a LOT of heat on high. The generator is sized to drive 2 burners, so when only one is in use, you get LOTS of fire out of it, if set wide open. I was running on unleaded gasoline, rather than Coleman fuel. I’ve run both and they both run about the same in this stove. (Not surprising since it was designed to run on both).
I put the oven, empty, on the stove and put the heat on ‘modest’. This on the primary (right hand) burner. It warmed over a couple of minutes toward 300 F. Then stalled. This was indoors with zero wind. The oven is thin sheet metal, one layer, no insulation. It has small ‘vent holes’ on the sides and the top to side ‘join’ is leaky. Flame is applied to a round port in the bottom with sheet metal inset and vents to duct that hot gas into the interior spaces. In short, your food is placed in a very large square flue for the burner, more than an actual oven space.
I cranked the heat up to high. A couple of minutes later, the front thermometer said 350 F (more or less, it isn’t very precisely marked and mostly gives 100 F marks and some dark lines between them where you can guess what they mean… But OK, the calibrated oven thermometer was placed on the wire rack at the middle point of the oven, same height as the one on the door. It did not agree when checked mid-warming, but eventually the one in the door caught up. Not that surprising as the calibrated one is low mass and the one in the door is, well, in the door and connected to more mass.
At about 4? minutes into it, they were both at about 350 F and the “new stove burning off” smell was modestly strong, so everything was getting pretty hot. On checking the interior thermometer, I noticed that the sheet metal in the bottom of the oven was glowing red in spots. OK…
I don’t know for sure if that is “normal” or not. The oven is described as aluminum coated steel, so unless the bottom panel is special, that will not do well with prolonged use at a dull red.
At this point I shut the test down as I was not keen on melted or red hot metal next to a gasoline tank on the stove all indoors.
I doubt that it was a significant risk, but figured it would be better to do any further testing outdoors on brick (and with the complication of wind / heat loss). That test will follow in a few days / weeks / whenever…
Some ‘reviewers’ had reported temperatures very different from the front gauge. Some had reported various kinds of cooking issues, from slow cooking to burned bottoms on a ‘cake’. Comparing what I observed to their complaints, I think the issue is just that the temperatures inside the oven will vary a lot. A flat ‘cake pan’ on the rack in the lowest position will be right above a red hot glowing hot air intake, while the thermometer will be well above it in an area where heat loss may make for much lower temperatures, where there is no IR heating, and where there is the potential for cool ‘down drafts’ near the walls.
Two reviewers said it worked better with foil over the outside. Essentially making it a little insulated and preventing wind from blowing in through the vent slots in the sides. (How you can keep a constant temperature in the box with wind blowing in vent slots in the sides is beyond me…)
It takes a very high burner setting to get to a normal baking temperature of 350 F (normal ‘middle’ setting. Slow cooking is 275 F for ‘oven BBQ’ while 325 F gives light brown on bread and 375 F gives dark brown crusts. 400 to 425 is good for biscuits and other fast cooking things that need some fast browning, and 450 F is a bit low, but OK, for pizza.) Fuel use will be quite high with the oven, even more in any kind of wind. For sporadic ‘treats’ when camping, like muffins that take 10 minutes, it would be OK. The irregular temperature can be compensated with cooking time and any burned / under done just part of the “camping experience”. As a ‘real oven’, it is a non-starter.
Yes, I’m complaining that it does OK what it was designed to do, and for not very much money; but it isn’t at all what it was NOT designed to be: a real oven.
As I bake bread every day or two, one of my ‘long term goals’ is to put an oven in the Patio Kitchen. I’d thought this might be a minimal / starter option. Something to ‘play with’ while figuring out what I really want. Maybe try some breads over a hickory fired stove too and see if wood flavored bread is a feature, or not. In reality it is simply too much of a giant heat leak to ever use effectively over a small ‘rocket stove’ design. (Maybe over a larger one?… but the wood use…) Furthermore, using it over a fuel driven burner, such as Kerosene, you are just asking for ‘strange flavors’. It likely would be fine over the typical ‘three rock’ or ‘fire ring’ camp fire with modest sized logs / lots of coals. It is mostly a tin box to put in a hot air flow.
So for my ‘ersatz oven’ on the patio, I’m going to try my “Dutch Oven” with a wind shield around it. At least then the pan in the pot is isolated from the flue gasses by a lid. Eventually, the “Patio Oven” will be a larger, heavier, much more expensive, but much more durable and energy efficient oven. Likely along the lines of the one used by my Amish relatives on their kerosene stoves.
This is a ‘camp’ variation on that theme:
It still says it is open in the bottom, so some “flavor tests” over various fuels with the Coleman will tell me if that’s a problem or not.
It’s black, has two adjustable shelves, handles for carrying it, heat reflectors along all sides and the top, and a door with a glass window and a thermometer. The bottom is open and the lower shelf has a heat shield underneath it to direct the heat towards the size (sic – Side?) of the oven.
The Butterfly oven is no ordinary camping oven. It is approximately a 13″ cube. It is very sturdy and does not fold up. Inside dimensions are 10.” high, 11″ deep and 12″ wide. The door opening is smaller, so for pan sizing, the door opening is 11″ wide and 9″ high. It will accommodate a 10×10 pan, which will allow a little air space around the sides for more even baking.
Other camping ovens on the market are not as sturdy and do not have the heat reflectors and air insulation pockets that the Butterfly camp oven has. This results in more even internal temperatures which results in a more pleasant baking experience. Assembly (somewhat difficult) required. (We also offer this oven ASSEMBLED for $10 more).
These folks have a nice picture of the inside where you can see a kerosene burner below in the opening. Lower price, at $55 as I type, too:
So the money on the Coleman will not be wasted. I’ll be using it for ‘stove sizing’ for an oven and for ‘flavor testing’ of open bottom ovens. It may well be that I have to ‘roll my own’ oven to keep food out of the flue gasses.
The “Perfection” oven has been around since ‘way back when’ at the time Rockefeller was making a kerosene monopoly in the world and trying to dominate the appliances as well. It was one of the products they ‘pushed’ to increase market penetration. It is the one more commonly used in Amish communities, but at $200 was a bit more than I wanted to spend on a ‘test’.
It is also unclear where the flue gasses go in the oven. I think it is inside the walls… but for $200 want to know that first. It typically was used on the matching stove:
I have a vague memory of seeing one of those in some house somewhere when I was shorter than the stove… maybe 3 years old? On some family trip somewhere that a 3 year old doesn’t quite bother to remember ;-) But the stove was interesting ….
In the end, it may just be easier to show up at The Mechanics shop with some sheet metal and glass wool packing and weld one up to my own spec. Flue gas in the bottom, around the sides and back, out a hole in the top. An outer skin holding the glass wool in place for exterior insulation. It would take a bit of fuel to get the inner shell metals hot, but then it ought to hold an even temperature very nicely on not much fuel.
At some point the Coleman Oven will be used in a ‘double shell’ experiment. Basically using it as the inner layer and just wrapping it in a gas conductive shell. Who knows, I might go so far as to make a ‘brick surround’ it can be set into. (Though the fuel needed to heat a brick oven is rather high…) So again, the money spent on it will not be wasted. Heck I might even use it to go camping ;-)
But what is very clear is that it isn’t a ‘Real Oven’. It’s a ‘toy oven’ for use when pretending to bake on a camping trip and making muffins or other fast foods. Not for a loaf of bread, nor for roasting a chicken for an hour+ as the fuel use would be horrific.
So I’m going to ‘play with the toy’… and that’s worth $40 to me.
But my search for a Patio Oven continues…
(For those ‘distressed’ by my resent focus on stoves, ovens, et. al.: Please realize that every year I review my “Quake Prep” gear and make sure I’m ready for “The Big One”. I’m also designing a Patio Kitchen since electricity in California is going “Crazy High” in prices. Besides, I really like cooking and cooking tools. I did grow up in a Restaurant Family and cooking from about 5 years old. As I’m throwing “time and treasure” at answering some questions about gear and processes and fuels, I think it of some use to document that. If you don’t cook, eat, camp, or care about fuel use; well, there are other articles. But yes, I am going to be “playing with fire” and posting about what works, what doesn’t, and what’s too expensive to be worth it. Eventually “Spring Cleaning” will be over and “Summer Build” too. Winter will come and outside fire based cooking will end for the year… Until then, it’s going to be Hot Fire, Cold Beer, and room temperature wine… with burned meat, wet slow cooked meat, roasted, fried, stewed, and whatever else vegetables, fish, birds and who knows what all. It’s ‘early spring’ here in California and that’s time to “Play with fire” ;-)