Explorations into Candle Stoves

Is it just me or is 6g to boil 455ml sounding remarkably efficient? If you can put up with the crap boil time…wow!

I think Mark might be really onto something here.

Yeah, it is… that's the beautiful potential of wax… FYI, I was planning on doing it myself, but have found with a young son and another child on the way my time is limited…

I believe the caldera cone system may lend certain advantages to a wax burning setup… the higher internal temps of the cone should result in a more complete combustion (read more heat and less soot from a smaller wick size). Also, the nature of the cone eeks more heat capture from a smaller flame size as well.

Actually, on a SP600 stove I got tap water to tea-temp / hot chocolate temp with JUST a tea candle… not quite boiling, but didn't hardly use any fuel either…

Note, Soy Wax should hold a lot of promise… not nearly the same kinds of organic contaminants that beeswax would hold, and not nearly the inorganic contaminants that makes paraffin nasty to deal with. Basically, it should be purer than either.

HAH! I was still typing whilst David was posting…

Hi Jason

> Would you guys say it's more or less than the amount you would get with a typical wood burning stove?
Mark needs to answer as well, but from my experience I think the answer really depends on how you run your wood fire. If you are using a good gasifier and wait until the initial flames die down a bit, then I think a clean-running gasifier would be cleaner. I THINK.

Yeah, the amount of soot I got from my trial was slightly less than I would have on a basic wood stove (something similar to the J Falk or Nimblewood)

"And I have not tried the cone with a candle, but one potential problem I see is that the cone is a "low oxygen" area (as the TrailDesigns folks note) and this could be problematic. But it is probably worth a try."

Low-Oxygen would only be an issue if you're vaoprizing fuel at a rate faster than it can oxidize (aka combust / burn).

The key is to keep the fuel-vaporization rate lower than the oxygen intake rate. If this is maintained the higher combustion area temps and longer heat retention time would make it advantageous.

"Also, if someone is clever enough to "gasify" the wax with a preheat tube or some such arrangement like liquid fuel stoves have, then one would have a potentially great stove."

Hmm… I wonder what would happen if one paired wax with a BB… probably wouldn't be true gasification but could get interested and be able to burn at a higher rate than the cone…

Ryan,

Interesting you should mention…, I recently built a donut prototype, but haven't had a chance to test it. I'll post the result when I do but it is likely to be a while before I get to it.

-Mark

Adam, if you're willing to pay for shipping, I'll box up as many as you like and send them out to you. The two part system comes in at about 70g for shipping calculations. The package seems to cost about $8-10. Maybe less if some power shopping techniques were employed.

Lemme know.

-Michael

Hi Mark and Roger,

Thanks for a great article I enjoyed reading it, I found it interesting that the waxes have higher heating value than propane/butane fuels and can be as efficient. I have done a lot of testing on canister stoves and with a non flux ring pot I use about 6g of canister gas to boil 0.5l of water. One thing that I have noticed is that with both canister stoves and alcohol stoves it is not less efficient to take longer to boil water but it can be much less efficient to boil too quickly.

I think you might find this interesting. I recently ran some tests on an side burner alcohol stove that I made, with a std aluminium pot and the same stove with a 1.5l JetBoil pot the std pot used 17.18g of denatured alcohol to raise 0.5l water 80C and the JetBoil pot only used 12.4g of denatured alcohol to do the same, but this dramatic increase in efficiency was not the same with other alcohol stoves.

I have done similar work on a Donut stove ( I called mine a central flue stove) I made it out of a piece of bar stock aluminium ( see picture below), it works ok but needs some tuning, the flame is a bit stronger than I would have liked because I think it has too much thermal mass.

Tony

JB weld is available in Australia. I have bought some at Bunnings or K Mart.
That coincided with me losing interest in making stoves…
Franco

Adam,
JB Weld is definitely available in SA at KMart, any problems let me know and I will try and get you some

Have you considered trying the Primus ETA pot? It appears to be wider than the Jet Boil and has a ring under the fins to protect them. I've heard reports that it halves the boil time with an alcohol stove.

Hi Adam,

I know you have been given at least one place to look for JB Weld in Australia so this may not be necessary.

When you posted your question I sent an email to the New Zealand distributor for JB Weld to ask where it was sold in Australia. I had exchanged emails with this person a few years ago. I just got an answer back from them and thought I would still pass it on to you. This is what they sent:
====
Contact the company below who are the Australian distributor. They should be able to help you.

Matt Allen
Finishing Services
tel 61 3 9553 2522
facs 61 3 9555 4048
email [email protected]

===

For New Zealand see:

http://www.jbweld.co.nz.

Hi Roger,

"I will disagree here. I don't think the thermal mass has anything to do with the amount of flame.
If there is too much flame it means too much alcohol vapour is coming off. You could reduce this by getting the flame further away from the metal (less boiling), or by covering the top ring and using jets to restrict the flow of vapour."

You might be right about the moving the flame further away but restricting the flow of vapor did not work with this stove, I have tried using jets (see picture below) and the stove used its fuel even quicker than the open top. I was trying to design an inside out Gram Weenie with a central flame to improve efficiency.

As part of another project I have been building a similar alcohol stove with the very thin aluminium Red Bull cans and I have had the opposite problem of not been able to get a strong enough flame, I moved the flame closer and I now have a nice flame.

Tony