Ideas for higher heat candle "stove"

[Anonymous]

I’m not necessarily looking to cook with it, though that would be a great option if I can optimize efficiency enough. Meant more to be combined with insulated tent for a “hot tent” set up (read more like, “warmish tent” set up).

I’m a complete noob when it comes to making stoves or the like, so any feedback from experienced folks would be more than welcome. The below ideas may be pretty ignorant–correction welcomed.

Some tentative ideas:

First, fuel sources. Beeswax is great stuff, but hella expensive. I plan to use some smaller beeswax candles more for light, than warmth.

Soy wax on the other hand, can be bought for around 24 dollars for 10 lbs. Lower combustion temp too.  I’m thinking of combining that with some bulk bought refined coconut oil (probably from Costco).

How to burn same?  Thinking of mixing in a half and half ratio, putting it in a largish tin.  I’m thinking of using some carbon felt as a larger surface area wick.  No idea if the following ideas will work, but this is what popped up.  Get some stainless steel mesh, roll it in a little, short pipe.  Put pipe upright in center of the tin. It will stick just slightly out of the wax.  Over that, put the carbon felt, which covers most of the surface of the tin.  The SS mesh pipe will keep it uplifted in the center (not sure what to do once the wax gets low, maybe just bend the top over?)

I’ll try it like that first, and then also try it with several regular candle wicks placed through holes in the carbon felt.

[Jon Fong / Flat Cat Gear]

By using carbon felt, you can make one mega-candle.  You will generate a lot of soot in the process.  As the mega-candle heats up, it will probably melt the surrounding wax so the wick should be supported and basically free standing.  The smell of burning wax is pretty profuse and will get into everything.  If you like the smell of wood smoke, you’ll probably like wax.  My 2 cents.

As a reference, I have found that 1 tealight puts out about 25 watts so probably 20 candles for a 500 watt heater.

 

[Anonymous]

Thanks for the info/feedback Jon.  Would CO be a potential issue if it becomes too “mega” of a candle?

[Jon Fong / Flat Cat Gear]

I have no idea, you might ping Roger

[Ben H.]

I just wanted to throw up a link to Jon’s candle stove:

https://backpackinglight.com/forums/topic/another-wax-stove/

Very impressive in my opinion.  To answer your question about CO.  I don’t have any direct knowledge, but my thinking is that: 1) candles tend to produce significant soot. 2) soot is carbon from incomplete combustion. 3) CO is also the result of incomplete combustion… so 4) you should certainly be careful about CO when using a candle in a confined space.  Probably not a problem with the standard wick candle, but could be significant if you are talking about 20 candles like Jon mentioned to get around 500 W of heating.

[Gary Dunckel]

Wait…I always thought that paraffin was a fairly soot-free (and safe CO) candle wax. Isn’t that what the igloo and quinzee folks use for light in those minimal ventilation abodes?

[Roger Caffin]

No, paraffin is NOT soot-free, and it CAN make lots of CO. If the flame is ‘bright’, it is probably making both.

In fact, within certain limits, ANY flame burning hydrocarbons can make soot and CO. To be sure, some oils are a bit less prone to this when burning in a small flame, but a stove is not a small flame.

Some folks may use paraffin, but that is more likely to be due to its ready availability and low price. As for having flames in a low-ventilation abode – Darwin rules.

Cheers

[Jerry Adams]

look at threads where David Thomas talks about wax stoves

there’s still soot, but not as much if you optimize the stove

the soot has a lot of wax in it, so it’s hard to get off of things

[David Thomas]

One the one hand, I applaud your interest in developing your own tent heater based on a wax fuel.  On the ever-present other hand (OTEPOH), I’ve got a chemical engineering degree and have been selling, repairing, using, and modifying backpacking stoves for 40 years now and I’m not sure I’d take this on.

It can be fun to reinvent the wheel, but you usually end up with a hexagon or ellipse instead of a circle.  Candles – been there, done that.  5000+ years of development have already been done.  White gas, propane, and butane stoves?  50 years of R&D, field testing, millions of units sold and lessons learned.

There are two things I’d do (and have done) with wax: use a wick in a small candle and use multiple such candles if I wanted more heat (i.e. a 100-pack of tea candles).  Or use a loop of wick in a large container (a loop of corrugated cardboard in a tuna-can of wax).  Those work.  They smell, make soot, and make CO.  But they work.  You have to play a bit with diameter, wick thickness and length, but you can figure that out with some trail and error.  (pro-tip: experiment outside).

If, however, I wanted a tent heater, I’d want to minimize CO production and not be spilling molten wax.  I’d either run the lowest-CO butane or white stove on the market, or (preferably) I’d run a catalytic heater.

Catalytic heaters will come with all sorts of warnings to not use them in enclosed spaces, but that is what everybody actually uses them for because the only way to heat up the whole planet is to burn fossil fuels for a century.  Easiest is to accept the pound of steel in a 16-ounce propane cylinder and buy a propane-fueled catalytic heater off of Amazon or at Walmart.  Here’s one for $30:

It’s 3000 BTU/hour (900 watts for you metric-weeines) and won’t blow up or spill melted wax.  If you buy bulk propane, ignore those pesky “$25,000 FINE!!” warning, and refill your canister without crossing state lines, fuel is only $0.80/pound.

If you don’t like carrying a pound of steel for every pound of propane (and who does?), there were white gas versions back in the day.  And now there’s eBay to help you recreate your childhood in so many ways.  Here’s a white-gas version offered for $60:

It ain’t UL, but it works, will emit FAR less CO than anything you or I cobble together in our garages, and puts out 3,000-5,000 BTU/hour.  And fuel costs a little over $1/pound.

Rule of thumb: Within 10%, all hydrocarbons have a heat of combustion of 20,000 BTU/pound.  Oxygenated hydrocarbons – IPA, ethanol, methanol are lower because 1) it’s partially oxidized already and 2) the weight contains some oxygen instead of using atmospheric air wherever you burn it.

[Roger Caffin]

Hi David

but you usually end up with a hexagon or ellipse instead of a circle
And what is the matter with non-circular gears? Like these for instance:

Just joking … (but such gears do work).

Cheers

[David Thomas]

I had a 15-speed road bike with elliptical gears on the crank gear set.  It caused the gear to do more work (move more chain) in positions your leg was the strongest.  I liked it because it felt smoother – it was a more uniform effort to pedal.

[DAN-Y]

Contact your local beekeeper and purchase hive wax from him and use it for your candles, much cheaper to go that route. Bees wax smells so good :-) for a night or two, see how you like it…nothing ventured, nothing gained.

[Anonymous]

Thank you for all the feedback Jon, Ben, Gary, Roger, Jerry, and David.  Quite the thread Ben.

Jon, that’s a pretty sweet stove.  You’re not selling any of these?  I’d buy one if it was reasonably priced.

Some points put into holistic context:

If I just accepted conventional wisdom, I wouldn’t have developed the most comfortable and cool rain system I’ve ever tried. Many folks on this site have said that you basically either have to accept waterproofness and some measure of discomfort due to lack of moisture vapor transference, or greater breathabilty and lack of waterproofness and thus also discomfort. Even though some of the sagest voices on this site repeated this mantra, I didn’t accept that this had to be the reality.

The tent in question will be pretty small (pyramid tent, about 47 inch tall at peak and 58″X58″ base [I’m short and will be sleeping diagonally]  and fairly well insulated (two highly water proof fabrics with 2.5 oz Apex, a layer of space blanket, little foam pieces to create air space for the former [NOT foam baffles], and maybe a little 700fp down and/or loose PP microfiber, all in between same).

I won’t necessarily need a mega super candle heater and it will surely have much more ventilation than an igloo (good size, fairly breathable insulation panel [much more breathable than average quilt]  on the front of door from bottom to mid way, and breathable peak vent panel and I live in a low snow area).

In any case, I plan on buying a CO monitor and doing repeated runs of home testing before taking it out backpacking. I have a while before it will be cold enough to take this out in the field anyways.

Who knows, experimentation might lead somewhere (and it might not).  Jon certainly made some strides in efficiency in his wax stove cooker.  Granted, he is a stove guru with tons of experience, but sometimes a fresh and beginners mind approach can result in innovation, if only by accident or intuition.  It’s worth at least trying, even if it doesn’t lead anywhere fruitful.  Sometimes the journey is more valuable than achieving a desired end goal.

 

[Anonymous]

That’s a good idea Dan, thanks.  Yes, I too like beeswax a lot.

[Anonymous]

If I could purchase a wax stove cooker from Jon or Dan (or if I somehow came up with a decent design myself), when not using it for cooking and just heating, if I had a strong pot support, I could use a pot I don’t mind dinging up, and put stones in there for a little latent heat after it’s put out for the night.

The pot plus stones would also act as a heat diffuser, and accumulate the majority of the waxy soot on the bottom of the pot. Unfortunately, I wouldn’t be able to use my Al pot for this, but probably could use my Ti pot.

[DAN-Y]

Some good information on using pure beeswax candles along with “Brass Followers”

https://store.standrewsalmanor.org/a-word-about-followers/

Made in the USA beeswax candles

https://www.dadantcandles.com/

 

[David Thomas]

“I plan on buying a CO monitor”

the cheapest option is the colorimetric monitor sold to pilots.  $5.  Less in quantity.

Qualitative rather than quantitative, still, it’s so small, cheap, and compact, that it wouldn’t be bad idea for anyone using a stove inside their tent to hang it in the breathing zone.

[Anonymous]

That’s dang cheap there David!

I think that would be a good to bring with me when on actual backpacking trips, but I want to measure actual levels during the home testing to get an idea of an average also. I saw some for around 25.

[David Thomas]

Or $9.85 at Walmart for a smoke-detector style CO alarm with digital readout.  But be aware that the smoke-detector styles are dampened and delayed in their response.  The first generation created so many alarms and responses by fire departments, that they changed the specs for only prolonged, elevated levels to give an alarm.  Years ago, someone offered an aviation one without the dampening and delays because pilots want to know right away if their cabin heat HX has a leak and exhaust fumes are entering the cabin.

[DAN-Y]

Oh the magic of Google

[Anonymous]

Thank you for the tip David.

That looks cool Dan. Somewhat similar to the concept of putting stones and/or dirt in a pot for more radiant heating.

I’d might use the flower pot system for home heating (with some modifications because they can be a little dangerous), but there is no way I’ll be carrying around flower pots on trips.  Stones are usually easy to find if there isn’t too much snow cover and Ti pot is pretty tough.  I usually park it not too far from a creek or the like, and it’s rare for them to freeze over around here, so at the very least I know I can find stones in there.

Modifications for flower pot home heating.  Make a (copper or aluminum) heat sink base for the candles, put them in a glass container so if the wax spills it’s contained, put a couple little holes in the pots above to allow better circulation, and put a little more space in between the candles and above pots just to be on the safe side.

[Anonymous]

I just came up with a cool idea to minimize soot/fume and CO build up while maximizing heating efficiency.  Going to build it before I share it.

[DAN-Y]

After reviewing the info found on google I came up with a waxy idea how to create a smokeless stove using wax. It will be the bestest yet 

[David Thomas]

I’m usually opposed to the hippy-dippy sorts and their Rocket Mass Heaters, soapstone stoves, and other forms of thermal mass (unless they’re willing to let the indoor temps swing between 60 and 80F – then the mass will do some good).  And I don’t want to carry flower pots with me while backpacking.

But I can imagine a thin-walled metal chimney (e.g. flue pipe from Home Depot) filled with (on-site!!!) coarse gravel / cobbles heated over a wood fire outside the tent.  The chimney does a lot for a cleaner burn and the induced draft literally “fans the flames”.  Two such rock-filled units in rotation could be releasing heat inside the tent while the other is getting heated over the fire.  No CO worries, no waxy smell, no fuel or mass to carry other than the thin metal walls and a few Ti stakes to retain the rocks in the duct.

[DAN-Y]

Posting the flower pot heater was to spark interest in conserving the heat radiated by 4 tea candles.

Capture the heat! Justin has an insulated tent, good start :-) He now has a source for CO detector(thank you David) He’s well on his way.

The technology is out there, all we have to do is apply it ;-)

[Author]

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