Moulder Strip Directions

Geek stuff:
The siloxane tape is interesting stuff, but I am going to GUESS that it won’t be as good as the Velcro straps and the silicone pad Bob M showed in posting #3496048.
My reasoning is as follows:
IF the (Cu or Al) strip does not conform exactly to the canister, THEN there will be very little physical contact area for heat to flow through. Heat transfer will need to be by another path.
But IF the contact area is enclosed by a nice wide insulating pad, THEN the air in there is going to get hot and the hot air will transfer heat from the strip to the canister.
On the other hand, if you don’t enclosed the contact area, then the hot air will escape from between the strip and canister, and heat transfer into the canister will be much reduced.

There are some corollaries to this.
If the physical contact is limited and the system relies on the hot air transfer mechanism, then the strip is going to get much hotter (to heat the air). That means you need to be a shade cautious about what materials you use as the insulating pad and the strap. Silicone for the pad would be fine, and nylon tape (Velcro) holding it in place should be fine. But some other sort of material like polyethylene which melts at a far lower temperature then either silicone or nylon might possibly melt. I have not tested this!
If you want to use a wet suit cozy, then you should check the materials. Neoprene foam is probably OK, but what is the knitted surface fabric? A silicone pad would of course make it all (probably) OK.
Is it necessary to enclose the entire canister in a cozy? I doubt it. Just a good insulation around the contact zone – like over the silicone pad and somewhat larger than it.
To be sure: keep the bottom of the canister OFF the snow!
Geek, geek, geek!

Cheers

Is it necessary to enclose the entire canister in a cozy? I doubt it. Just a good insulation around the contact zone – like over the silicone pad and somewhat larger than it.
To be sure: keep the bottom of the canister OFF the snow!

It really is as simple as that.

I like to use the cheap N-butane (with various other ‘pollutants’ as Jerry has documented) because its much higher vaporization temperature exposes issues with cold canister operation at much warmer ambient temps than the usual isobutane/propane blends.

With commercial blends containing propane (even the Primus “summer” blend in my photo a few posts up-thread), when the copper HX strip is used I have only noticed stove performance sagging when all these conditions are met: 1) the ambient temperature is 25°F or lower, 2) a 220g canister is in use, and 3) when said canister’s fuel level is low, say 20% or less remaining. In this instance a canister cozy helps. I have run 110g canisters totally empty at -5°F with no cozy.

With straight-up N-butane, however, IME it is always good to use a cozy (and insulating platform) because with a vapor temp of 31°F combined with the effect of evaporative cooling, performance drop-off can already be seen with ambient temps as warm as 45°F.

But this is not going to be a problem for the vast majority of people because there are very few of us who refill canisters with N-butane.

yeah, cheap butane is good for testing because it has a higher boiling point so you can see cold degradation at a higher temperature

if you’re not a super cheapskate or testing cold performance, just get the stuff like MSR Isopro that says it contains isobutane.  That works down to 20 F or so without anything.  It might start slowing down some when the canister is mostly empty.  I think most people don’t camp below 20 F

I discovered silicone tape over a year ago, and I’ve found it to be interesting stuff. It likely won’t be useful for this discussion, but it has lots of other uses. I make lightweight pot lids from a silicone baking sheet (or over liner or whatever). The only thing that sticks to silicone is, you guessed it, something else that is silicone. So for a little ‘handle’ to lift the lid off the pot I use a piece of Rescue Tape (another brand of silicone tape). I carefully clean the surfaces of both the lid and the silicone tape with alcohol, dry it off, then press the tape onto the lid. Things stick together pretty well, but I can also remove the tape (with some difficulty) if I need to. A buddy that works at my mega hardware store mentioned that pure silicone caulking adhesive ‘might’  make the bond more permanent. I haven’t tried that, mainly because there’s no need to. It would be nice if someone made tiny tubes of that adhesive, like Super Glue and Gorilla Glue do for single use.

Another use I’ve found for my Rescue Tape is to secure a small piece of evo foam to create a good index finger rest on each of my trekking poles (why is it that no one makes a pronounced finger rest on their trekking poles any more?). The key thing there is to stretch the silicone tape as you wrap it around the pole handle, When you’re done, the sil tape wants to return to it’s original shape, but it can’t, so you have a tight, secure wrap where the sil tape sticks to itself. When this is done, I slip the right size baby sock over the pole’s handles. This way, I don’t have to deal with a rubbery handle, and the socks absorb any moisture from my hands. This whole mod adds about 0.5 oz to the pair of poles, but it makes me happy.

Silicone tape will always be in my arsenal of MYOG supplies. However, I don’t see an application related to the Moulder Strip concept.

Hey Gary…are these the socks you use?  Just want to make sure I get the right ones :)

Ha, JCH! Kinda, but sorta not. I’m all about garnering squirrel respect, you see, so I go with Superman or Batman socks so they know who’s boss. But actually, my favorites are black ones that seem to absorb hand sweat best. The key is to get the right size, which are pretty small (for ages 6 mo.-9 mo. or something).

I am also all about Scunci silicone hair ties, which are the finest ‘rubber bands’ on the planet. I place a medium one at the bottom of each baby sock to keep them in place. I will sometimes put a large one on each pole at the top, out of the way. I connect the trekking pole handles with 2 of the large ones to make an inverted V to support my Contrail.

(end of my usual thread drift…)

Gary –  Just wanted to maker certain I correctly identified you if I ever see you coming down the trail :)

Seriously tho…you do not find that the socks squirm around or bunch up or create wrinkles?

No, actually. They work fine if you use the right size baby socks, and of course the right Scunci.

I’m optimistic. The 1.5″ tape is going to work just fine for holding the strip to the canister and will be able to be reused several times changing from one canister to another. It will work much better than a spring and string. The strip needs to be made so that for a surety it conforms to the curvature of the canister. Make it right!!! Think POSITIVE ;-)

The 1.5″ tape is going to work just fine for holding the strip to the canister
I agree that it should work – but would like confirmation :)

and will be able to be reused several times changing from one canister to another.
That’s the bit I hesitate over. I have used siloxane tapes and expanding tapes before, and my experience has been that they are not so good the 2nd time around. BUT – I just don’t KNOW for this stuff.
And I also worry about dust and dirt – we all know how well that sticks to silnylon fabric.

We need actual field testing.

Cheers

Roger, order a roll of the tape and help the forum members out in the name of stove science. ;-)

LONG delivery times to Australia.
Besides, it’s a group effort.

Cheers

I just ordered a roll from aAmazon and will be part of the group effort. Roger…you missed out on a group tape test opportunity. 

Hi Dan

No worries. I will wait to hear from you and others how it goes.
Will you be able to pass some tape on to others?
Um – can one peel off a foot or two of the tape without triggering it? Important question actually: can one take a bit of spare tape in one’s kit?

Cheers

Roger, In another thread you recently mentioned that a synonymous name for this technique (warming gas cylinder with a heat shunt) is the “alpine bomb.”  Can you share some of the background of that version of the nomenclature?

See for example http://www.ademiller.com/blogs/climbing/2005/12/gear-the-alpine-bomb.html

Gear: The Alpine BOMB
31st December 2005, 06:36 pm

Or, more aptly, how to modify a cannister stove to work in really cold weather. This isn’t my idea. It was published years ago in Mountain Review magazine (issue 7 page 74). It also appears in Mount McKinley Climbers Handbook, Glenn Randall (page 32). The version shown here is much simplified and not adapted for hanging. I also use a wind shield with it (not shown).

A leter version may be found at http://gearthirty.blogspot.com.au/2012/03/alpine-bomb-for-msr-reactor.html, although it references the above.

Earlier references are hard to find on the web, mainly because they are older than the web. But I knew about the idea around the 1980s, when all we had were the Bleuet canisters. They were and still are n-butane (and are dangerous things).

Cheers

Roger, when you go out in winter conditions, how many canisters do you consume in one outing/trek/walk-about(average)?

In the extreme temperatures, when the Moulder strip is necessary, is the strip applied to the canister at home prior to leaving?

Could the strip be permanently applied to the canister with JB Weld and considered a consumable? Several canisters could be prepared ahead of time in that fashion and have no need to do change overs of the strip in the harsh climate conditions. Does this idea have any merit?

Silicone tape comes in different sizes and colors:

https://www.amazon.com/X-Treme-Tape/b/ref=bl_dp_s_web_9346923011?ie=UTF8&node=9346923011&field-lbr_brands_browse-bin=X-Treme+Tape

Product description
X‑Treme Tape’s strength comes from both its thickness and the advanced bonding characteristics of the special silicone formula. X‑Treme Tape has about 15% more material/thickness than rival brands making it the most reliable product available.

Um – can one peel off a foot or two of the tape without triggering it? Important question actually: can one take a bit of spare tape in one’s kit?

Cheers

Yes Roger, it can.

Bob,

In your experience is there an upper limit on the number of minutes you can continuously run the stove (As in melting dry western powder snow into several litres of water/ melt water for a group) before the canister gets to the point where you dont want it to safely get any hotter?    IIRC your trip reports are often solo for a night or two, so I’m wondering if there’s a diminishing rate of return where at some point with longer trips and more snow melting/stove usage  required where it would be preferable to bring an inverted cylinder stove?

For context I have an inverted canister stove, Optimus virga, with an in-flame preheat loop and am wondering whether it still has a logical place in the stove quiver, before I start sourcing a copper strip to save the ounces.

And to BPL members generally, do we keep calling this technique ‘Moulder Strip’ or ‘alpine bomb,’ the latter clearly being the older?

I vote Moulder Strip : )

I would second the “Moulder Strip”.  Bob’s post was the first time I’ve seen someone really put in the time to test the safety and efficacy of the technique.  The velcro/silicone/copper assembly also makes for a relatively standardized device with consistent performance.

(It’s also easier to explain in the airport security line.)

-J

“…the latter clearly being the older.”

Wait a minute, Bob’s pretty old himself. I mean, maybe he was one of those dirtbag rock climbers that coined the term ‘alpine bomb” in the first place. Then he comes along later and polishes the design – that deserves some big-time credit, don’cha think?

Besides, like somebody else said, “Moulder Strip just sounds cool.” So…as long as I live (if I live that long) I will call it that. YTMV (your terminology may vary).

Hi Dan

Roger, when you go out in winter conditions, how many canisters do you consume in one outing/trek/walk-about(average)?

Based on records from 10+ years for trips up to 3 months in length, we use about 30 g of fuel per day in the summer time for TWO people (my wife and myself). That’s a cold breakfast (muesli), morning tea (coffee and tea), cold lunch, snack in PM, and a cooked dinner with washing up. I have managed to drop that figure of 30 g/day down to about 22 g/day with extreme care once – I had miscalculated during planning … (oops), but 30 is easy.

Record keeping: I weigh the canisters before and after the longer trip and records the weights with felt-nib on the underside. On some really long trips in Europe I recorded the number of days per 450 g canister.

For winter in the Alps I allow double that: 60 g/day for TWO people. But winter can be variable: sometimes I warm the milk for breakfast, and sometimes I have to melt a bit of snow for water. It takes the same amount of energy to melt snow to make 1 L of water as it does to bring that 1 L of water from ‘cold’ to the boil. That said, I am fairly good at finding access to water under the snow in Australian conditions. So fuel consumption in winter varies over a range depending on conditions.

To be sure, light weight is the goal, but not at the cost of suffering (too much) in the snow. That is not just uncomfortable, it is distinctly hazardous, and we do this for fun. So I make sure I am carrying 60 g/day for the full length of the trip. If there is a little left over at the end – smiles all around.

Cheers

Opinion:
Alpine Bomb or Moulder Strip?

The early Alpine Bomb designs were based on very heavy gauge copper wire beaten flat and crudely held against the canister – but they worked, and established the concept. Bob’s efforts took that basic rather crude design and turned it into a neat flat copper strip shaped to the canister and held in place with a Velcro strip and a silicone pad.

A number of us have shown that thicker soft aluminium may also be used and is a little lighter, but that is an engineering detail. Both materials work.

Frankly, Bob’s design looks far more couth and professional, as well as being something any MYOGer could copy. Credit where credit is due, imho.

Cheers

Alpine Bomb or Moulder Strip?

Having coined the terms, of course I support “Moulder Strip” and, if distinctions are needed from the variety of other materials and geometries proposed, then “Classic Moulder Strip” (CMS) for a strip of copper sheet metal.

We already have to combat a lot of confusion and excessive caution about its use WHICH IS ONLY FOR WINTER CAMPING CONDITIONS!, and “Alpine Bomb” would make that a lot worse.

“In your experience is there an upper limit on the number of minutes you can continuously run the stove (As in melting dry western powder snow into several litres of water/ melt water for a group) before the canister gets to the point where you dont want it to safely get any hotter?”

Kevin,

BobM, DavidG, GaryD, myself and others have run lots of tests on CMSs and variants of it.  So while Bob’s actual use to make breakfast on the trail is pretty short, back home in those test sessions, I’m often doing multiple pots of snow melting and water boiling. I’ll have the stove running for a hour sometimes (swapping variants out, but quickly restarting the stove) which would be an unusually long usage on the trail and yet the canister never gets overly hot (because we’re testing in sub-freezing conditions).  Everyone else reports the same, sometimes with thermocouple data nicely graphed.