Fire Maple Star 1 (HX System) weight hack

[Jon Fong / Flat Cat Gear]

OK, here is a fun and relatively cheap hack for you guys.  I recently bought a Fire Maple Fixed Star (Heat Exchange) cooking system on Amazon for $41.95.  The price goes up and down a bit but it is still pretty cheap.  It is a tank at 18.8 oz, so I spent time figuring out how to strip down the weight.  The final result is a cooking system that is around 10 oz.  With a windshield, the performance is about on par with the MSR WindBurner.  Details are in the video, enjoy!

Initial 18.8 oz

Final ~10 oz

 

 

[baja bob]

Widesea has a similar setup sold on Amazon for $46. You get a .5L pot, .8L HX Pot, very large windscreen, stove, fold-up stand for the gas canister and a bag. Stove (2 oz), windscreen (2.7 oz) and HX Pot (5.9oz) come in at 10.6 oz. Remove one of the silicone covered handles and you get to 10.1 oz

https://www.amazon.com/widesea-Cookware-Equipment-Backpacking-1-2Person/dp/B09TT169T8/ref=asc_df_B09TT169T8/?tag=hyprod-20&linkCode=df0&hvadid=598348773578&hvpos=&hvnetw=g&hvrand=7521557069488482235&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9031023&hvtargid=pla-1730300971818&psc=1

[Tim (Slowhike) Garner]

Nice work Jon!

[Kevin Babione]

@Baja Bob – Does the Widesea setup come with a lid?  It looks like it’s designed so that the .5L pot is meant to be the lid for the .8L HX pot.  Coming up with a lid on my own wouldn’t be tough, and in spite of Jerry’s testing, I like a lid on my pot when heating water.

[Jerry Adams]

I use lid too : )

[Jerry Adams]

Nice video Jon.

[Jon Fong / Flat Cat Gear]

The TOAKS D115 replacement lid works fine on the WideSea pot.  Add another $10 to the total.  My 2 cents.

[baja bob]

No lid with the Widesea kit.  I was actually intending to buy just the HX pot and then get one of Jon’s setups for it and saw this kit with a stove and windscreen included for an extra $18.  It has what looks like a Soto knockoff that comes with the 3 prong pot stand that runs $10. Figured I could use it with my Windmaster. Haven’t tried any of it out yet.

[Jon Fong / Flat Cat Gear]

After working with a lot of HX pots, I have discovered that not all HX pots are the same. The pot for the Fire Maple Star X1 far outperforms the Fire Maple 1-liter pot. Same manufacture, slightly different pots. The Star X1 gets about an 80% efficiency (n=6): on average, it took 4.5 g of fuel to boil 500 ml of 20 C (68 F) water. Additionally, performance in the wind is about on par with the MSR WindMaster: boils 500 ml of 20C water using 6 g of fuel). I am still digging into why there is such a difference.

[Bill in Roswell]

I wonder how the Star X1 pot would compare in efficiency with Jetboil Stash HX pot?

[Jon Fong / Flat Cat Gear]

Well, it’s time to starting think about HX pots as a system and not just the pot.  The Stash is fantastic in fair weather conditions but performs horribly in the wind.  The robustness in the wind has to do with how the stove couples to the HX pot.  For some reason, JetBoil decided that just resting the HX pot on what is basically a simple canister topped stove would work well.  It doesn’t.  The Fire Maple Star X1 mounts the stove to a flate plate and the HX mug sits on the plate.  It is significantly more robust in the wind compared to most other HX Systems.  My 2 cents.

[DAN-Y/FANCEE FEEST]

[Bill Budney]

it’s time to starting think about HX pots as a system and not just the pot.

How do heat exchangers work? It looks like a reverse heat sink: collect as much heat as possible from the stove head, spread it and store a little for slower delivery to the pot (for greater efficiency of heat transfer over time). Is that about right?

If so, then doesn’t a tall, somewhat snug-fitting, windscreen do most of that job without the weight of the heat sink? I’m thinking like ocelot or cone windscreens; with only a small gap between windscreen and pot.

In my head, I’m picturing that the windscreen would store a little heat in the air volume, then apply it to a large area of the pot; not just the bottom, but the sides as well. While not as good at the job as a heat sink, I would expect hot air to do at least part of the job? Does it work better when the heat sink is almost as tall as the pot (for greater contact area between pot and hot air)?

 

[Jon Fong / Flat Cat Gear]

I am pretty sure that if you developed a mug with fins on the bottom as well as up the sides that you would create a highly efficient system.   Light weight HX mug cost $20 and can weigh in the 4-5 oz range and when properly configured can boil 2 cups with about 5 g of fuel.  Let’s say someone develops an HX mug with additional vertical fins that can boil 2 cups using 4 g of fuel, cost $30 and weighed an ounce more.  Is the 1 g savings worth an additional $10 and 1 oz?

[Bill Budney]

Let’s say someone develops an HX mug with additional vertical fins that can boil 2 cups using 4 g of fuel, cost $30 and weighed an ounce more. Is the 1 g savings worth an additional $10 and 1 oz?

An ounce more than 5 oz? I’m not really the right target for that… I have enough trouble justifying 7 oz for a canister. But I’m sure that some customers would love to get 20% more efficiency for $30. Is that about 30% more efficient than a non-HX mug?

If it must be HX, then how about a lighter heat sink? Having to buy a special mug is kind of meh. MSR makes an HX gizmo for (almost) any mug. Aluminum heat sinks are not as good as copper, but they do work. If you could make a lighter HX adapter that works with any mug, then that would be noteworthy.

Still, I’m more curious how the HX stacks up to your best Ocelot setup? I’m just guessing about what I wrote in my first message above, and you’ve probably done the tests. I’d be more interested in a windscreen designed in a way that maximizes heat transfer without the HX mug. If you had a windscreen that delivered half of the efficiency gain of HX without the extra weight, then that would get my attention.

 

[Jerry Adams]

That’s like my derivation of an old REI product

aluminum with steel wire connector, 1.25 ounces

serves as a HX and a windscreen

I forget the efficiency – not as good as some reports of real HX pots.

With any addition, including a HX or a lid, it’s hard to justify the weight with the weight of fuel saved.  I think the only possible exception would be a windscreen if it’s windy.

Normally, only the exhaust gas that passes close to the pot transfers heat to the pot.  With a HX, some of the exhaust gas that flows away from the pot and is wasted, will heat up the HX fins, and heat will be transferred from the fins to the pot.  Also, the HX can direct the exhaust gas flow closer to the pot.

[Bill Budney]

Right, thanks for putting a picture to this idea, Jerry.

I’m thinking that a well-designed windscreen could do most of the job without the weight of HX.

Could be part of why cones are popular for low-power burners; they do an almost perfect job of collecting all hot gas and forcing it around the pot? Would need some adaptation for an upright canister stove, but maybe fine as is for a remote canister stove.

Not sure that the cone shape is necessary for any reason other than stability.

[Jon Fong / Flat Cat Gear]

Of anything, I think that you would need to have vertical fins bonded to the mug to further act like a heat sink.  My 2 cents.

[Bill Budney]

OK, I’ve prototyped a proof of concept that boils 30% faster. Ordered a better scale for more precise gas measurement.

To really test the concept I should probably compare it to an HX mug. Does it matter which one? I don’t want to carry an HX mug, so my only reason to buy it is for testing. That Widesea for $20 sounds ideal for my purpose, but does it perform as well as other HX mugs? No point in doing a useless test.

 

[Jon Fong / Flat Cat Gear]

The WideSea is pretty good. Looking forward to seeing your prototype.  If you don’t want to buy a high resolution scale, just do 5-6 boils and look at the total amount of fuel used.  My 2 cents

[Bill Budney]

OK, thanks. WideSea ordered. Scale arrives tomorrow… it isn’t fancy; just better than my kitchen scale. Good idea on totaling multiple boils.

If my concept works then I will certainly post it. If it turns out to be stupid, then I may not. :)

 

[David Gardner]

Wow Jon, MSR Windburner-like performance at 1/2 the weight is really impressive.

[Jon Fong / Flat Cat Gear]

For optimal results, you do have to use the Windshield and you have to point it into the wind.  Since the wind does not always come from the same direction, some diligence is required.

[Bill Budney]

Interim Report: The WideSea HX pot is better than I expected. As far as I can tell, it is merely a fraction of an ounce heavier than the record-holding Sterno Inferno (which has been selling on eBay for absurd prices recently). The HX pot weighs about 4 oz more than a 600ml titanium mug (but would decrease if I did surgery similar to Jon’s above).

Goal: Efficient burn without the weight of a heat exchanger (HX) pot.

Hypothesis: My rough estimate is that the WideSea HX adds about 80 sq cm of surface area. It also focuses the flame. A heat shield that heats the sides of the WideSea non-HX pot/mug adds more than twice that surface area. Unless other factors are involved, the heat shield should be more efficient.

Based on (small) 200-ml boils, I’m getting about the same efficiency (in grams of fuel per boil) with the heat shield. Boil times have been slightly longer with the heat shield vs the HX pot; possibly due to lack of the flame-focusing effect of the HX pot.

Next tests: Larger water volumes and more test runs for hopefully improved accuracy.

Refining the goal: Right now, my unoptimized prototype heat shield weighs more than the HX pot’s added weight, so no real benefit yet. In order for this to be a success, the heat shield must weigh less than the HX penalty of 2 -4oz (depending on which non-HX pot). Not sure how much I can shave off yet, so TBD.

TLDR: The heat shield concept works, but requires a lighter (more expensive) pot as well as a lighter heat shield in order to save much system weight. It remains to be seen whether this experiment will be worthwhile in the end. Clearly the WideSea HX delivers good performance per dollar. The 4-ounce weight penalty only sounds like a lot until you compare it to the weight of a single freeze-dried meal (roughly the same).

 

[Jon Fong / Flat Cat Gear]

Post a picture! it would be fun to see where you are heading.

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