Another look at the “Fire Focus 14” ESBIT burner

Interesting, Eric. So, basically about the same time to get water to a boil, but the FF14 held the boil longer.

If the FF14 holds the boil longer, it must be controlling the oxygen flow to slow the burn — yet the time to boil is the same, so it must be (as it’s name would imply) indeed focusing the heat.

HJ
Adventures In Stoving

I'm expecting mine to arrive any day now. I worry less about times and more about fuel economy.

Dare I hope to boil four cups of water with one Esbit tablet?

Where would one find a picture of it?

Thanks

Derrick

Look HERE

Thanks

I am really impressed, Eric. Thanks for sharing this!

Waiting for mine to arrive. Can't wait to try it out in the Sidewinder! I <3 ESBIT

KJ

Ian,

Interesting question, will the Focus Fire 14 boil 4 cups of H2O on one ESBIT tab?

First I'd want to use the Cakdera Cone with fitted pot. This is because the CC appears, in my experience, to be the most efficient ESBIT stove available. All other stoves let too much heat escape before it even touches the pot.

My pot is only a 3 cupper B/C I wanted a small pot for solo cooking so I can't use it for a 4 cup test. A larger Tri Ti or aluminum CC will be needed. I use a 1.5 L. JetBoil pot on my Sidewinder but only with wood for winter snow melting. The JB pot sits on top of the Sidewinder with the fins outside the Sidewinder's top.

I doubt if just one tab will do it but it may work with a 1 qt. or 1 L. FITTED pot in the CC. Likely 1 1/2 tabs will work well.

BUT… the Focus Fire 14 will only hold one tab. I wish Jon would make the "chimney" just a bit larger so contain two 14 gram tabs stacked or side-by-side. A taller chimney aould also have the result of giving more "draw" (faster air flow from the bottom air vents). However this may result in shorter burn times – I dunno.

But I'm working on a taller 2 tab chimney that also holds the tablets by the sides like the CC Gram Cracker does, to restrict burn area. If it works Jon can have the design gratis. For me it's all about making ESBIT a better alternative to alcohol. ;o)
So far playing cards and tape seem to be the best template materials for experimenting with shapes for aluminum and ti sheet metal.

Eric, do you light the cube first and then put the burner over the top of it or can you light the cube through the burner top?

Thanks for the results of your tests.

DY
Adventures In DIY Stove Making

Thanks Eric. I have the sidewinder paired up with the Evernew 600ml. My plans are to burn seven tablets each (40* water) with the gram cracker and Jon's creation to see how they compare.

For the way I cook, I really don't need the water to come to a boil but I've been on a mission to boil 4 cups at 40* and keep coming up short.

Hello everyone,

The Focus Fire 14 is an experiment of mine to produce a highly efficient Esbit based stove. By my calculations, the stove has a fuel efficiency of 66%. This is not quite enough fuel efficiency to boil 4 cups of water starting at 70 F, but its close. That being said, the stove was designed for people who boil 2 cups or less per meal. My thought being that this would be the sweet spot for this design. This is a straight up stove and does not have the simmering capability of the Epicurean Stove.

I believe that this is also a pretty niche stove with limited appeal; of course I may be wrong. Anyway, the Focus Fire 14 is in the pre-ALPHA stage of development. I am looking at getting feedback from people to see how I can improve the stove.

Best regards – Jon
wwww.flatcatgear.com

Thank you, Jon. And would the FF14 be more efficient than an Epicurean if the Epicurean were in “high” (air holes down) mode? I assume the Epicurean would be more efficient if the Epicurean were in “low” mode, but that running in low would take “forever” to boil water.

HJ
Adventures in Stoving

The Focus Fire 14 was optimized for efficiency

The Epicurean Stove was design for dual burn modes: Primary being the low mode (baking), Secondary the high. Low burn rates do not always mean more efficient.

Hey Jon,

First, thank you for being willing to cater to the very small customer base that this product is designed for. Those who use hexamine fuel tablet has always been small, but with the help of guys like you and others out there, we are helping to push forward some of the safety aspects of using hexamine fuel tablet when compared to alcohol for fuel.

I have a bit over 60 burns using the FF14 at this point.

Except for on the first day that I acquired it, I have used 4g esbits exclusively. I did use one 14g on the day I got it, just to test it out, but I am a 4g esbit user.

Using two different 400ml pot setups I find it takes:

6 grams to reach shrimp eyes – about 70-80 °C (155–175 °F)

8 grams to reach crab eyes – about 80 °C (175 °F)

10 grams to reach full boil – 100°C (212 °F)

I do not time how long it takes… that is for those who care more about things than I do.

I do not know how cold the water is… what kind of a hiker carries around a thermometer and sticks it in the water before they heat it up.

All of my testing has been done at elevations below 100 feet.

I have gone through about 1000 of the 4g esbits over the course of the 2013 hiking season and without using the FF14 I would say it is saving about 2 or 3 grams of esbit per heating, over not using it.

I am not really sure how consequential that is for the average hiker. For myself, at the amount of days I have done this year, and with about 1000 cubes burned through, and an average of it saving 3 grams per burn, if my math is right (which it usually is not) that would be a year-long saving of about 3000 grams / 105 ounces / 6.5 pounds – over the course of the year.

At this point in time I would have three recommendations for it:

1) The little triangle where the clip goes into should be a square, the triangle causes it to either not stay in there or to come apart when it heats up.

2) Consider making a two piece version. The design makes it a very odd shape and difficult to find a good spot when using these 400ml pot setups that some of us do. Having it in two pieces would allow us to shove it down into different spots in our cup along with the rest of the stuff.

3) Try to resolve the heat flexing issues, that you and I have previously discussed, so that the FF14 remains flat and does not result in warping and lifting up of the edges and thereby allowing extra oxygen into the unit, and/or allowing flames to be released out the corners.

Again, thank you Jon for helping out those of us who are out there using hexamine fuel tablets as our source of heating water while on the trail.

+John Abela

Interesting design Jon :-) Nice and light.

Hi John, I was bale to watch your video using the FF14. John Abela’s Coffee Time on youtube I could see what you were saying about warpage of the burner. I also noticed that your Ti cone was warped way out of shape and was allowing a lot of air to enter from under the bottom edge. I feel you should get better results if both warp issues were eliminated. What is causing the warpage of the cone?

That’s alot of stuff you’re putting in that little pot :-)

DY
Adventures In DIY Stove Making

John,

Thanks for your feedback. I am compiling a wishlist of potential changes to make on the next round. I have a solution for the flexing issue and I am thinking about a better way to join the two halve. After I get a complete list, I will cook up a new version. Best regards – Jon

Using two different 400ml pot setups I find it takes

John, how much water was in that pot? One cup? Two cups is about 475 ml which doesn't fit very well in a 400ml pot. :)

6 grams to reach shrimp eyes – about 70-80 °C (155–175 °F)

8 grams to reach crab eyes – about 80 °C (175 °F)

10 grams to reach full boil – 100°C (212 °F)

Hey! Enough with the technical talk. How about you put it in terms an average Joe like me can understand? ;)

HJ

Wow John, you are using 4 gm. tabs and here I am trying to make a FF chimney that will take two 14 gm. tabs for longer burn time.

I guess we have really different approaches with ESBIT stoves. I boil for FB cooking and actually cook at times.

When my boiling or cooking is done I blow out the ESBIT flame and re-use the leftover fuel for the next meal, usually adding 1/2 a tablet to it to get a complete burn with no fuel remaining. Sometimes I blow out the flame on a new tab after cooking but re-light it later for heating up dishwashing water.

As for warping of the long edges of the FF 14 chimney I'd recommend titanium for a material that will resist deformation from heat. I'll probably get some from The Ti Goat soon. GOD! This ESBIT stove tinkering is as bad as alky stove tinkering! It's addictive.

Anyway, the quest for ESBIT burn efficiency continues. Personally I feel the Focus Fire 14 is bringing us even closer to "maximun" efficiency nirvana. For me a 4 minute longer burn time means a lot.

@DY — you sir, are a freaking master!! I got my package yesterday. Cutting half the weight off the system in the video you linked too AND it includes a lid that actually STAYS on!!! The master has done it again!

@Jon — that is pretty much all that data that I have mentally kept track of that I was able to recall. If there are any other questions you have, just drop me a message.

@Jim — water in the cup in the video… hmmm, probably 375-380 ml. I had to give myself room for the coffee :-D

As for the ‘lingo’ lol. It use to be listed on the ‘boiling’ page of wikipedia but some dweeb decided to remove it… but you can still access it in the history page.

@Eric, I have never really been one that cared about really long burn times, I just want some dang hot water lol.

John Abela said:
@DY — you sir, are a freaking master!! I got my package yesterday. Cutting half the weight off the system in the video you linked too AND it includes a lid that actually STAYS on!!! The master has done it again!

Canadian Postal Service is dependable :-)

Back in August I created a thread here just for you concerning the contents of the package I sent. Not a one person was interested in it’s contents so I have not pursued such a light weight kit. You are now the owner of the one and only prototype. I want to make another kit and need you to check the height of the pot for me please.

Here is the thread:

SulYte Gram-Splitter XULyte Gram Reduction Kit

Eric, any more testing on the FF14?

DY
Adventures In DIY Stove Making

Dan,

I'm still trying to get a template that JUST fits two ESBIT or FireLite tablets and still looks like Jon's prototype chimney. I want to get it exactly correct "in the flat", like Jon's unfolded chimney that he sent to me.

Also I'm trying a roll-up cone-shaped chimney with two bottom vents
that may work well with Ti sheeting.

When I do get one of them to work properly I hope it will still work with one tablet but I may have to use the Gram Cracker base (not sides) to hold it high enough for good flame above the chimney.

Conversely, if the "24 gm." larger chimney won't work well with one tablet I can always carry Jon's original chimney in addition, which weighs a bit less than the complete Gram Cracker.

One thing is for sure, Jon's base pan for the chimney absolutely must have the corners sealed to contain all the liquified ESBIT fuel for a longer burn time. My best job of sealing the corners came when I used small strips of aluminum Refletex tape. Perhaps heavier aluminum muffler tape would be best for durability.

Research is SO tiring. I think I'll have another IPA to speed up my creative thinking. ;0)

I think the shape of a flame coming from a rectangular chimney will quickly become round once it leaves the top of the chimney so why not use a round container with enclosed bottom to retain all liquid esbit? You really don’t want a pinpoint source flame on the bottom of your pot. A 2 inch diameter flame is ideal for smaller pots.

I once did an experiment with a pinpoint source of heat using a cone shaped device for concentrated flame. I named it “Stiletto Stove” It’s in my archives at bplite. Once the water was at boiling temperatures, the large vigorous boil bubbles were directly in the center of the pot where the pinpoint heat source was. The column of rising bubbles was about 1″ in diameter. The diameter of the pot was about 5″ It was interesting to see such a small column of large bubbles within the pot.

DY
Adventures In DIY Stove Making

I found that round opening don't work well. The rectangular opening is sized to create the right area to perimeter ratio to control the airflow. Best regards, Jon

BTW, The Focus Fire 14 does not create a point source as the pot to flame opening distance forces the flame to spread out .

"Gram Cracker" is my favorite new gear name, ever. Brilliant.