Moulder Strip Directions

[Roger Caffin]

Hi Bob

We specialise in geekiness…
But I don’t see that a spring and a bit of string qualifies as complicated and kludgy. It would work in the dark at -10 C. A lot simpler than nylon webbing, buckles, silicone pads, etc. Hum?

Cheers

[Bob Moulder]

So let me get this straight… for one of the leading backpacking stove experts in the world, a man of science and engineering… a Velcro cinch strap is complicated? 

 

 

[Roger Caffin]

Yeah, I’m stupid. My wife says so.

What does the velcro cinch strap weigh?

Cheers

[JCH]

I try to stay away from online controversy and avoid anything that has even the faintest whiff of trolling, but I’m going to break all of my self-imposed rules of internet decorum and wade into this all the way up to my nose.

It’s very hard to read the last series of posts from Roger and Jerry and not come away with a sense that there is more than a bit of axe grinding going on.  Why are you both seemingly so intent on dismissing this concept?  Roger is one of the most knowledgeable people on the planet when it comes to backpacking stoves, but could it be that having put quite a bit of effort into solving the cold weather canister riddle, Mr Caffin is bothered that someone stumbled upon a simple and elegant solution with a slight tweak of an idea he had dismissed?  Or perhaps it is simply a case of looking after his financial stake in a stove business into which much thought, energy and effort has been invested.  It’s much more difficult for me to suss out why Mr. Adams is tagging along.

Mr. Moulder, Mr. Dunckel and Mr. Thomas have posted a great deal of testing data and statistics that show the HX strip, when constructed and used as specified by Mr Moulder, works well, is cheap, and lightweight to boot.  I encourage Mr. Caffin and Mr. Adams to post their data showing that it is not, or that another (their?) solution is superior.  Let’s be clear…I’m not asking for photos of deconstructions using large stainless steel hose clamps or other silliness.  Let see some cold, hard facts and rigorous analysis similar to that supplied by the gentlemen in the HX strip discussions.

And in case my point has been missed thus far, changing the design of something such that it’s performance is diminished, and then claiming the original design is flawed is at best specious, if not obviously self-serving.

[James Marco]

This IS backpackingLIGHT. Anything that will do the same job at less weight is good. Personally, I use a simple Hair Tie and Aluminum strip. Seems to work fine down to about 25F and it works on both sizes.

[Jerry Adams]

sorry JCH, I must not have been clear enough

I think all of these techniques work good.  It’s really just subjective which one an individual will prefer.

And this is the beauty of BPL.  Lots of good ideas.  People can try different ones that might work for them.  Many ideas will not be so good for an individual.

Any disrespect I have given to anyone is just my bad attempt at humor.  Techno geeky people tend to get into endless arguments about unimportant details leading to disrespectful Trumpian exchanges is all I’m laughing at, we seem to avoid that here, at least 95% : )

I’ve taken data to a geeky extreme, see https://backpackinglight.com/evaporative-heat-loss-in-upright-canister-stoves/ and parts 2, 3, and 4.

The physics says aluminum has a little less thermal conductivity but weighs about half as much as copper, so if you make it a little thicker, it will work the same but weigh less.  Since this is backpackinglight, people go to great extremes to save a little weight.  Actually, using aluminum instead of copper could be cheaper.  Usually, the question is how much will you spend to save an ounce of weight.

My problem is it doesn’t get very cold here in Portland.  If it ever got cold enough, I might verify that an aluminum strip with a short stove and a 110 g canister works good.  With a tall stove and 220 g canister and an aluminum strip that’s sized to work the same as Bob/Gary’s copper strip, it just barely keeps up with the evaporative cooling.

I used to do this for a living, but this is much better because I can just do what I feel like doing.

[Jerry Adams]

I don’t think Roger’s stoves are a huge profit making business, more of a hobby to entertain himself.  I don’t think he charges too much.  Many people have been happy with his stoves.

[Gary Dunckel]

James, do you use a silicone hair tie, or something else? I’d like to see a photo of your setup if you wouldn’t mind.

JCH, I have similar feelings. Bob and I have been rather disappointed with some of the responses that we’ve received about our copper HX strips over the past couple of years. Some people have poo-pooed the concept without actually trying it out for themselves. I have come to not really giving a hoot about that anymore. I have a setup that works flawlessly for me, and that’s all that matters. I can’t be bothered with people that post just to be posting, thinking they are actually contributing something to the science being discussed, when in fact they look foolish, unscientific, or just lazy.

[JCH]

Gary – Well said.  I respect your honest, measured response and agree wholeheartedly.  Over many years I have developed a well tuned bulls*t sensor, and have a hard time remaining silent when it goes off…the recent turn of this thread has it screaming.

James – I think we would all like to see your hair tie solution :)  Please do post a photo if possible.

[Jerry Adams]

“Some people have poo-pooed the concept without actually trying it out for themselves.”

I didn’t mean any disrespect.  In fact, I have tried all of your techniques.  Not too much with copper just because I have aluminum handy.  To me, copper and aluminum are interchangeable.  If you make the aluminum a little thicker.

And I appreciate that after haranguing people for years you tried the aluminum reflector. : )

[Bob Moulder]

With a tall stove and 220 g canister and an aluminum strip that’s sized to work the same as Bob/Gary’s copper strip, it just barely keeps up with the evaporative cooling.

I took the photo below last winter in Harriman State park, Feb 15. Ambient temperature was 14°F.

The fuel canister was a partially full (approx 60%) 220g Primus summer blend. I bought a few canisters of this online from a German supplier because I couldn’t find them anywhere in the US. These canisters sat in the basement for a long time because very shortly after I bought them I figured out that the whole issue of fuel blends became totally irrelevant because my copper HX strip permitted the use of N-butane at below-zero Farenheit temperatures. So I took this large canister on an overnight trip just to use it up.

When I took out the stove in the evening I discovered that the HX strip setup I had stored in the MiniMo pot was one for a 110g canister, so I had to use a short copper strip with the larger canister, and with no cozy. As you can see in the photo, I used some rubber bands and a Snow Peak ‘hot lips’ silicone piece to secure the copper strip to the canister. This setup worked just fine. I started it with no pre-warming (it got down to 10°F overnight) of the canister and I let it run for well over 20 minutes to see if the performance diminished, but it did not.

It might be the case with aluminum, but in the case of copper this whole insistence that the strip must be very tightly clamped to the canister is just plain wrong. As I have stated time and again — and has been demonstrated in MANY actual field tests — the curvature of a copper strip doesn’t need to match that of the canister all that closely to work well. This was an early assumption of mine, as well, but much testing proved it to be incorrect, as are the assumptions about the length of the strip, as shown below.

What this whole exercise has taught me is that one should not make assumptions without testing, nor make sloppy, lazy inferences that different materials are going to behave the same as theory says they should.

If you guys want to pursue the use of aluminum as a heat shunt in this application, perhaps it is best to start a new thread and have at it. I promise I will not come and piss on your parade as you pursue your avenue of inquiry with the same openness and rigor as I have mine… at least as long as you don’t insist on repeatedly misrepresenting my findings.

Fair enough?

[Bob Moulder]

Thanks, gents, good observations.

Gary and others, I was still writing my screed as you posted….. it took longer than expected because in the middle of composing it my wife made me take the dog out for a walk.  ;^)

[Jerry Adams]

again, sorry, I really appreciate your testing and posts, the copper strip is an excellent way to use butane at lower temperatures

[James Marco]

Sorry guys, pictures are still being a “witch.” I still have to get the program, but I have been really lax about things…working with Lean2Rescue these days…

Anyway, 25F is not that cold. It worked enough to make coffee and oatmeal for myself and daughter and maintained itself for the three pots necessary for our breakfast.

We were using a JetBoil SOL (Aluminum version.) The strip was from some scrap sheet roof flashing (HD stuff, not sure of the exact size.) I used it to make some step flashing around a chimney for a friend, cutting it by scoring with a utility knife and bending.) About the same as Aluminum siding for thickness.

The low end was about an inch and a half wide and sat against the bottom crimped edge of the canister. (The slight bend at each cut came in handy.) The other end was trimmed to fit up into the burner section, I think this was closer to one inch. I did this on site so didn’t measure it. I used a small found stick to apply pressure to the flashing after roughly forming it with my finger. Bob said this is unnecessary for pressure (I pretty much agree) but the metal strip was fairly warm to the touch and I was afraid it would melt the hair-tie, but, it stayed fairly tight throughout the burn. I believe the fabric coating helps it.

Anyway, I slipped the hair tie on, then slipped the strip on. Then rolled the hair tie up for leverage and added a piece of a stick. After about a minute of operation, it melted the end of the flashing in the flame, but, I ignored that. Too long was my supposition. Anyway, after it melted, I turned it off (trimming the end with a knife) and it did NOT repeat.

The strip itself got hot and conducted the heat down to to canister as Bob describes. I had the old SVEA, but was wondering, so, I just hacked off a strip and tried it. Worked OK. I am guessing if it got much colder, I would want a thicker strip. Likely, this would have prevented melting, but this depends on how much extra you leave. It looks like the quenched flame in that area actually cools the metal somewhat…only a guess based on a couple observations. So, a lot would depend on where you end things near the burner. I will note that the heat will also be reduced, since, it is traveling away from the HX fins on the cup. But, this effect always happens in cold conditions. To pay extra fuel to make something work (aka “priming”) and is fine with me. I have done more car camping with Lean2Rescue than I have done for the past 5 years combined, rebuilding 4 lean-to’s with them in the past few months.

When I am out hiking, I usually take a butane lighter (usually in my pocket) and warm up the bottom of my canister to work with Roger’s Winter Stove (or warm it over a fire for 15-30 secs.) I shake it and start the stove, then flip it after a few seconds (between 5-30.) In cold weather (spring and fall) I always bring the SVEA and forget the extra weight. Hot breakfasts and hot suppers are quite important in rain, snow, cold winds, and, the low temps…

Good trick, Bob!

[Bob Moulder]

James, the Bic canister warming trick was shared with us by David Thomas.

[David Thomas]

 

“What does the velcro cinch strap weigh?”

Mine weighs 2 grams.  I find them at Home Depot next the electrical extension cords, a few dollars for a dozen.

And that’s all I need down to 0F.  I didn’t try the really skinny light velcro during my tests at -15F and -21F.  Then, I had a thicker, fuzzier, wider (1.5″) piece of double-sided (loop on one side, hook on the other) Velcro that also served as a cozy – 15 inches long handles any canister and weighs 9 grams.  Less if for a 110-gram canister only.  You can see pics of that Velcro at my post about testing Moulder Strips and Gardner Gadgets one morning in Fairbanks: https://backpackinglight.com/forums/topic/testing-moulder-strips-at-15f-26c/

[Casey Bowden]

Not to derail this thread, but did the Point Reyes Hot Tub happen last weekend?

[David Thomas]

Casey,

Alas, no.  I spent that weekend, Monday and Tuesday, at a remote hydro facility (Bradley Lake) at the head of Kachemak Bay out of Homer, Alaska.  When that came up, I had to cancel my plans for the Point Reyes Gourmet Trip Reunion.  I went with a 30-pound, 110,000 BTU-hour inline water heater and a BBQ propane tank and left those in Castro Valley after I tested them.  I’d hiked out to Coast Camp 2 weeks prior and the water faucet in camp had plenty of flow and pressure.  I’m sure it would have all worked (although taken 3 trips to pack it in.

The water heater was actually pretty versatile – there are adjustments for heat rate and water flow.  The only tricky bit for remote use is that you need 12+ feet of head for the water.  For showers, that could be a bladder or bucket hauled up into the trees.  For a hot tub, you’d need a spigot with water pressure or a LOT of hose to tap a stream high above the tub.

So I’m lot more ready the next time it comes up.  And it was educational for me to learn how inexpensive some inline water heaters are now.

[DAN-Y]

Has anyone tried this 1.5″ silicone tape? Does not have adhesive on it, just sticks to itself, can’t weigh that much using 1.5 turns of tape.

[Roger Caffin]

I suspect we have a bit of a culture clash here. Engineering types LOVE to argue about technical details – as Jerry pointed out way back the thread (#6067). That may be confusing to others from different cultures. Relax guys: we all love each other, and we do LISTEN to each other and LEARN from each other.

David T was on the mark when he posted the actual weight of a bare velcro cinch strap. The small plastic D-ring will add weight, but that looks like being lighter than I had expected. I was assuming heavier Velcro (to get higher pressure) and so on.

Bob’s observation that the curvature of a copper strip doesn’t need to match that of the canister all that closely to work well is interesting, and does indeed partially contradict what I had been assuming. I suspect that a tighter fit might speed up the feedback effect, but that too is an assumption. The silicone pad probably helps there.

The bottom line I get out of all this is that Bob, Jerry and Gary have made a significant contribution to the general knowledge of how to use upright canister stoves in cold weather, and that benefits all of the UL community. That’s great, and is the core of BPL.

Cheers

[Bob Moulder]

Looks like a good candidate, Dan.

My first thought concerned whether it attracts dust and loses its stickiness over time.

I read through the 4 pages of product questions at the end and did not see this addressed.

[David Thomas]

Dan: Nice to know about.  Fabulous temperature limits.  I can imagine using that on a water hose with a pinhole leak or securing a wire splice.  Maybe as an insulating layer on a pot handle?  I ordered some up.  I’m kind of a tape geek and keep my favorites in stock at all times.

[Ben H.]

…My first thought concerned whether it attracts dust and loses its stickiness over time…

– Bob M.

I looks like the tape has a plastic film that is peeled off the unrolled tape, so that would support the concern for attracting dust and grime.  Plus, someone in the Q&A mentions that the tape is not very reusable.

 

[Roger Caffin]

It probably has a siloxane-coated surface. That is the silicone-based adhesive they use to make sealing tapes which bond to a silicone coating (think seam-sealing silnylon seams on my tents). Expensive stuff, or it used to be. But if correct, it would suggest it is really a fix-and-forget material rather than a reusable one.
My 2c.

Cheers

[DAN-Y]

I’ve used the tape for plumbing issues and it is very sticky stuff. I’ve used it to create a pot gripping surface but it was insufficient as an insulator for my sensitive finger tips.

I’m not a canister person so I’ve strayed away from experimenting in the name of stove science.

I hope someone can do some experimenting with the Moulder Strip and the silicone tape.

I have a little knowledge that makes my life interesting ;-)

 

[Author]

Posts