How did your DCF shelter age (and expire)?

[Dan @ Durston Gear]

DSM told me recently that the backpacking market is about 50% of the total DCF consumption, with sailing and the military as some other big ones. Right now DSM is in the process of potentially selling off their materials division, so I highly doubt they’d want to reinvent DCF manufacturing in the near term. But longer term, if there was a coalition of gear makers that wanted it they might be able to band together and get convince them to develop efficient manufacturing that keeps the cost about the same as regular DCF. However, quite a few DCF companies don’t seem to be concerned about it, and for the ones that are, there are still ways to design around those limitations, so it’s a hard thing to rally around.

The other challenge is education. If the tents cost 10-20% more yet 90% of customers don’t know the difference, then the pricier tents won’t sell. To sell those, a company would have to educate potential customers that it’s worth it, which is a tough sell since bias stretch is a boring topic for 98% of people and DCF seems to be working well enough right now even when it’s not designed to consider this, and very well when it is designed to account for this, so the improvement in actual customer experience would be slight. I’d like to see HB DCF at the same price and agree it’s an improvement, but I do think with careful design it doesn’t matter too much to real world users.

[Stumphges]

Jerry, you gotta think that sailmakers would certainly benefit from HB DCF. How could they not?

But the sailmaking market doesn’t seem that big, either, from the figures Dan has shared. I wonder what share of the sailmaking market (high-end, technical sails) DCF has. If I were a sailmaker, I would want something with bias stability, and we know that there are other options out there for that.

[obx hiker]

“If I were a sailmaker, I would want something with bias stability”

Wonder how many have voted with their feet on the current iteration?  Seems to me sails ought to be a larger market than 50%. What are kite boarders using and etc etc?

[Roger Caffin]

There is a difference between kite boarders and yacht owners. Kite boarders do it for fun, and on a limited budget. Some yacht owners are the same, but there are always the very rich who are desperate to beat ‘their friend Fred’, and for whom the budget does not matter.

I gather that there is a fine line between coming in first in a race and bursting the spinnaker because you have pushed it 1% too hard.

Meanwhile, the rest of us are happy with nylon: a very forgiving material.

Cheers

[Jerry Adams]

There was that video of making a sail.  Narrow triangles of fabric sewed together so most of the tension is along the grain of the fabric, radiating out of the corner.  They worked around the problem of tension on the bias.

I don’t think sail users care as much about weight of fabric like backpackers

I’m surprised 50% of DCF goes for backpacking tents.  That could be enough of a market.  Adding fibers at +- 45 degree angle isn’t technically that difficult?

 

[Jon Solomon]

We’ve been told for a long time that markets promote innovation.
Obviously that’s just not true — at least the way today’s markets are organized.

I admire savvy designers like Dan and Henry who can account for the limitations of non-HB DCF and design accordingly. Imagine what they could with HB DCF.

Perhaps a decade from now, or sooner, DCF will be challenged by other options. Perhaps silpoly; perhaps something new. I don’t understand anything about the limits of polyester but just looking at the development of silnylon it might be possible to predict a timeline. After 30D silnylon became the gold standard of the UL backpacking world and launched a number of famous cottage brands (both Tarptent and MLD began with 30D silnylon), it took something like 10 to 15 years to bring to market lighter sil alternatives that offered most of the strength with similar benefits. Perhaps the same thing will happen with silpoly. When that happens, maybe whoever owns DCF by that time will finally pull HB out of the hat.

Education may be a lost cause, as Dan says, but that doesn’t mean that it wouldn’t be possible to generate widespread enthusiasm for products manufactured with HB DCF. People don’t need to be educated to be enthusiastic, especially given today’s online swarm culture. If anybody could generate that kind of enthusiasm, it would be people like Ryan and Dan, working together with other manufacturers and aided by a swarm of prosumers and early adopters attracted by the superior function and aesthetics.

 

 

 

[Stumphges]

Dan’s idea of the DCF makers coming together to buy the DCF product line sounds good, an UL Co-Op?, but seems unlikely to happen. I think Jon is on the right track with what might motivate change.

Regarding sails, recall that the sailmaker pattern we discussed did orient the panels along the “grain” of the fabric, but also that the makers chose a bias-stable fabric for that design. It may be that orienting fabric so that the tensile forces on a static sail (panel) are along the grain is sufficient, but that one still wants stiffness and strength on the bias to handle panel (sail) deformation resulting from impact with a wind gust (or even steady wind pressures).

Roger points out that nylon is a very forgiving material. It is stiff enough, but not too stiff, and is very elastic. When a gust hits a silnylon panel the yarns stretch a little bit along the grain, but almost never beyond the limit of their elasticity. Similarly, when a panel bows inward it will deform along its biases, but the silicone coating is absurdly elastic and will spring the panel back into shape immediately after impact.

Without bias stabilization, the same gust will be met with virtually no stretch along the grain of a DCF panel, but mustn’t there be deformation along the bias? If so, that deformation will be permanent.

Although Dan has argued that clever reinforcement obviates most of the problems with DCF, I’m not so sure. Consider Henry Shires’ comment here:

General suggestion for minimizing fabric deformation in DCF tents is to keep the forces aligned parallel to the fabric surfaces and to do what you can to keep all the forces equalized and running through reinforced areas. DCF will permanently deform in high stress areas over time but as long as the deformation is in line with the normal tension points then the effect on overall performance is low. Where you run into problems is with mid-panel pullouts and force lines orthogonal to surfaces areas as those will create “bubbles” in the surfaces and the structure will suffer in the wind.

The bold sentence is essentially what bothers me about DCF. Deformation is inevitable. It can be minimized, but it can’t be prevented. And I’m not entirely convinced that the effect on performance is necessarily low.

I suspect that if users took careful ridgeline measurements of new tents and then measured, them again at intervals of use, we’d learn that these shelters are slowly melting over time.

I think that a lot of this is going unrecognized because many of the DCF tent designs on the market are not really designed to be taut, precision-built structures. Look at the photos of the tents on the Zpacks site. Most of them don’t pitch taut at the factory. Are we going to notice deformation in those things? Probably not until there is failure like that shared by Arthur.

I guess from that perspective, precision-built DCF tents like those from Tarptent, and by the sounds of it Durston Gear, might be the bellwethers. How they age might tell us a lot.

Aside from measurements, another thing that would be illustrative would be photos of pitched tents throughout their life spans. Presuming that a user can produce a consistent pitch, changes in the tautness of the panels and hems over time could serve as indications of plastic deformation. That would make for an interesting thread.

 

[Sam Farrington]

Having rejected DCF long ago, I had forgotten what Dan pointed out way earlier in this thread; namely, that it has a warp and a weft like most fabrics.  The only problem is that the threads, strong as they may be, are visibly separated from each other, as seen in fine insect netting.  Were nylon or polyester woven in this fashion it would be useless, for tents anyway, because coatings would not reliably fill the gaps, and it would not be waterproof.  It would also not be able to hold its shape under stress, particularly from those guyouts  Zpacks slaps onto the middle of tent walls to add space and stability (and stake weight).  Even with the mylar plastic sealed to it, I’ve observed points on DCF where the weft threads shift sideways, opening up larger areas that are protected only by the fragile mylar. No surprise then that DCF does not hold its shape.

Kudos to those like Henry who have designed tents to minimize the drawbacks of DCF.  You don’t need statistics to see that backpackers are crazed by the prospects of lightening shelters, the one thing we cannot do without.  Not that many don’t try to.  Dan commented in an old thread about backpackers heading for town on the PCT when it rained, or worse, when their flimsy tarps were blown down.  But for those who carry tents, it can be hard on the back.  Maybe not right away.  But with lots of treks over the years, it becomes apparent.  Take Nimblewill, for example.  Early on, he found a safe and reliable tent design that greatly reduced his shelter weight, and has recently completed the AT again (in segments) at 83 years of age.  And the design is still marketed by Judy Gross, but no longer in DCF.   So it should come as no surprise that dedicated backpackers will pay dearly and risk safety to be able to carry a superlight and reliable shelter.

Ahh, if only I had a dependable, tiny shelter weighing almost nothing, and could backpack endlessly.  In reality, shorter hikes can be just as enjoyable, well almost.

[Monte Masterson]

Meanwhile Tarptent, ZPacks, Gossamer Gear, MLD, Locus Gear and others will collectively sell thousands of DCF tents in 2022. Mainly to consumers who are willing to deal with a shorter lifespan and higher price in order to be much lighter and not have a tent that’s a wet sagging sponge every morning. And please don’t try to convince me that silpoly doesn’t hold water. Granted it’s not quite as thirsty as silnylon, but it still retains a lot more water than DCF.

The lightest silnylons weigh between 0.8 oz to 1.05 oz (7D’s to 15D’s) and only 15D silnylon 6.6 would come close to matching the strength of .51 DCF. And there’s no ripstop silpoly I’m aware of lighter than 20D. Even if there was you couldn’t trust it because polyester is not as strong as same weight nylon. Silpoly of 20D weight is the lightest I would consider going, and it’s WAY heavier than DCF. And I’d still bet on .51 DCF over 20D silpoly in powerful winds. Now 20D silnylon 6.6 is a different story.

[Jerry Adams]

I mostly agree with that

I had my silpoly mid in the rain, shook it off vigorously, put in plastic bag until I got home.  20.9 ounces when wet.  14.6 ounces when dry.  So it gained 42% of it’s dry weight.  I assume most of that is just water stuck to the outside of the fibers.

I think the 1.1 ounce/yd2 silpoly from rsbtr is strong enough, but you need slightly improved technique.  For example, run a reinforcing strip from the tent stake loop up to the peak of the tent.  And the standard reinforcing circle on side tent stake loops – with 1.5 oz/yd2 silnylon you don’t have to do that in my experience.  But most people do that anyway on silnylon.

If you’re camping in high winds probably silpoly isn’t a good choice.

[Murali C]

I am surprised that storm worthiness of DCF keeps coming up. I have been in thunderstorms and hard rain in my DCF tarps over the years and nothing has happened. In gusts where the whole tarp shudders with every gust of wind changing direction every few seconds.

I am sure 95% of folks do this – find trees/boulders to act as barriers for your shelter. If you are above tree line and there are no barriers to buffet the winds etc, that is a different story. There as well, if you are expecting storms, go down tree line and find some barriers.

Usually I will hear stories of people getting wet from their nylon tents. Stupid designs like put the mosquito netting first and then the rain fly next. I mean who designs stuff like these?

I think we tend to pack our fears most of the time. Sam – you should get a Zpacks Pocket tarp or Zpacks Altaplex tarp and a bathtub ground sheet – you will not get wet. They provide 360 degree protection and the bath tub will protect against splashes. If you want added peace of mind, get a the 0.74 version.

[Sam Farrington]

Correction:  From my last post:  “Were nylon or polyester woven in this fashion … ”  

That implies that the warp and weft threads are woven together on DCF.  But close examination of the samples where the Mylar was pulled off by opening Hysol bonds shows that the warp and weft threads are not woven together as in a typical fabric.  Rather, they are just laid one over the other before the mylar sandwich is bonded by the autoclave.

[Jon Solomon]

Happy New Year, everybody.

Not sure I agree with some of things being said here. DCF holds surface water. How much, I’d like to know with specific tested weights. In the absence of tested weights, I’d hazard a guess and say that soaked DCF will easily hold a couple hundred grams of water weight.

The 20D silpoly from RBTR is okay in most situations but is basically spineless in strong wind. I think Henry said as much in a thread somewhere explaining why he hasn’t moved to that fabric. My experience bears that out. I’ll still use it but am looking forward to trying a shelter made with the 30D silpoly from ET.

If this thread has shown anything, it’s that talking about fabrics independent of design and use scenario is of somewhat limited value. Heck, people have been dealing with poorly designed Zpacks DCF shelters for thousands and thousands of miles. More power to ’em.

0.51 DCF is strong enough for wind but a little bit questionable when it comes to large hail stones and other flying debris. True, there have only been a handful of documented cases of failure in hail. But last summer in Europe we had some freakishly large hail stones recorded in the Alps. I suspect that with the way we’ve been beating on the earth’s climate systems, such irregularities will become more frequent. 0.8 DCF is a minimum, I’ve concluded. Sil fabrics are even better, given their inherent plasticity. Unlike DCF, they bounce back. Sure, the UL code teaches us not to pack our fears but that doesn’t relieve me of making a sober assessment of changing, volatile conditions.

In the case scenarios I’m familiar with, a pocket tarp wouldn’t cut it. I’m talking about exposed situations where the terrain offers little or no blockage and winds don’t come at you from just one direction. Lateral rain, cross winds, and even gusts from above are not to be written off. Often you don’t have a choice about where to pitch, bailing out isn’t an option, and getting down below tree line means at least an extra day given my limited walking speed (yep, pushing 60 here).

Gusts that make the whole tarp shudder are a design issue, as far as I am concerned. I recognize that for many it doesn’t matter but for me it essentially means a night with little or no shut eye. Been there, done that. I’ve been through my share of nights in a shelter that gets me through the night but requires a nap or more to regroup the next day.  These kinds of situations happen to me frequently enough and I’m not willing to compromise on route selection and campsite choice that I’ve decided that I might be willing to carry an extra 200 grams for that security and peace of mind.

YMMV,

[Roger Caffin]

Meanwhile Tarptent, ZPacks, Gossamer Gear, MLD, Locus Gear and others will collectively sell thousands of DCF tents in 2022. Mainly to consumers who are willing to deal with a shorter lifespan and higher price in order to be much lighter
Me, I am a contrary curmudgeon, I know. But I would rephrase that thus:
Mainly to consumers who are willing to deal with a shorter lifespan and higher price just for the glamour of DCF.

The idea of trying to sleep under a shelter that shudders with every gust – oh wow! How exciting! Sigh.
I would be very perturbed if my tunnel tent showed anything more than a faint twitch in a gale. But it doesn’t.

Oh well, HYOH etc.

Cheers

[Sam Farrington]

“Sam – you should get a Zpacks Pocket tarp or Zpacks Altaplex tarp and a bathtub ground sheet – you will not get wet.”

Murali, you also referred to “… gusts where the whole tarp shudders with every gust of wind changing direction every few seconds.”  This is typical with an inelastic fabric.  Nylon will hold it’s shape throughout gusts that are severe because it is elastic, and the fabric is woven.  Unfortunately, it loses this quality when it becomes wet.  But not so much with a 6.6 nylon fabric.  And it remains to be seen whether better coatings can help with this.

Won’t comment about Zpacks shelters because haven’t used them.  Make or mod my own shelters, and they remain stable in windstorms, not just because of the fabric, but also because of the design.  But agree that getting below tree or timberline in vicious weather is best for a good night’s sleep.

With respect to getting wet in a single wall tent, that is about condensation.  True, the mylar on DCF collects less condensation.  The was shown years ago by the late Jack Stephenson’s experiments with bonding mylar to nylon tents.  But the comments on BPL about swabbing condensation off the inside of single wall tents, including DCF tents, are legendary.  Did not stay dry in tents until went to double wall.  After that, no problem.  Also, you are using tarp shelters that ventilate, and that cuts condensation.  The problem with that is ‘horizantal rain.’  generated in wind and rain storms.  Stopped using tarps long ago.  This tunnel tarp condensed severely in storms, and rain also blew inside even when awning covers were unrolled over half of the tunnel ends:

It was pretty stable in just winds, though, and did not shudder a bit. That photo was taken on top of Mount Madison in NH’s Presidential Range. It was off-season so we were allowed to set up our tents.

[Murali C]

I agree with Jon about DCF retaining water. I have had a camo tarp which retained more than the 0.51 one – but, yes they do retain water a little. Maybe not as much as the silnylon ones.

After 20-25 miles, I am out. Gusts/thunderstorms don’t bother me.

A good bathtub is what protects me from the rain in a Pocket Tarp. And I have lots of those stick on loops on the inside of the pocket tarp – almost 10 of them to hold the bath tub in place:-) Lets see what kind of deformations happen:-) I will report back on how many nights I have spent on this 0.51 Pocket Tarp.

Sometimes I feel like these discussions are like predicting when condensation happens. Lots of theories – I bet you will not be able to predict if you are going to have condensation on a particular night. And of course lots of you will say you can predict it very well:-)

[Murali C]

I am also talking about wind speeds where the hiking pole flexes and goes back to its original shape making the tarp shudder.

[Sam Farrington]

Murali, I do not rely on predicting condensation, or for that matter, other conditions. I prepare for them.

[Murali C]

I am just kidding light heartedly Sam…..:-) that sometimes field usage and predicting problems are two different beasts. But that said, I am learning a lot from this thread – but will continue to add stick on loops etc to my DCF tarps. I am pretty comfortable with DCF tarps after using it for the last 5 years.

[Jerry Adams]

Good information here.  Some ideas may seem to contradict others but whatever…

When I use my 0.44 inch pole in my mid it flexes if it’s very windy.  Then the entire tent flaps around a lot.  But that pole is pushing it.  The 0.65 inch pole is better when it’s windy.  I haven’t noticed it flex.

Sometimes when it’s windy my tent will flap around and I’ll worry about it collapsing. Then, it doesn’t collapse and I’ll just go to sleep.

I have had tent collapse before, but it was because I was experimenting.  With a poorly reinforced silpoly as I’ve mentioned.  Or when I stupidly used that 0.44 inch pole.

A couple times tent stakes have pulled out.  I use those 6 inch stakes that aren’t very strong.  Until I put big enough rocks on them.

[Monte Masterson]

Roger stated regarding DCF tents: “mainly consumers who are willing to deal with a shorter lifespan and higher price just for the glamor of DCF. 

Okay, if shedding A LOT of shelter weight and not dealing with near the water absorption is glamorous then you can count me in. And respectfully Roger, I realize you’re more of an alpine backpacker than most us ultralight fringe cases. If I ever take a notion to get into mountaineering I’ll go with a red label Hilleberg….heck, maybe even a black label.

Jon wrote:  “I’d hazard to guess and say that soaked DCF will easily hold a couple hundred grams of water’. 

What? Maybe before the tent is shaken hard and/or wiped down with a camp towel. At least the water can be mostly purged from DCF whereas a wet silnylon/silpoly shelter will have to be laid out in the open for an hour or more to get even close to becoming dry. There’s no comparison when it comes to water retention, DCF is immensely better.

 

[Jon Solomon]

Hey Monte, I humbly accept the challenge. This is BPL. What we need are numbers.

FWIW, I’m like Roger. Nothing is better than gettin’ high and stayin’ high…for as long as possible.

[Roger Caffin]

At least the water can be mostly purged from DCF whereas a wet silnylon/silpoly shelter will have to be laid out in the open for an hour or more to get even close to becoming dry. There’s no comparison when it comes to water retention, DCF is immensely better.
Lots of heresay, but do we have any actual measurements?

Yes, I have had a few saturated nylon 6,6 tents, so to speak, but I have not noticed any significant water absorbtion in terms of mass. Maybe I just missed it, but I suggest hard numbers are needed here.
(I do not count tents covered in hard ice: a different matter!)

I often say that when you can measure what you are speaking about, and express it in numbers, you know something about it; but when you cannot measure it, when you cannot express it in numbers, your knowledge is of a meagre and unsatisfactory kind; it may be the beginning of knowledge, but you have scarcely in your thoughts advanced to the state of Science, whatever the matter may be.
Lord Kelvin, speaking to the Institution of Civil Engineers, May 3, 1883

Cheers

[Roger Caffin]

A lot of the Hilleberg tents are for forested conditions with not too much wind. This may reflect some intelligence in the designers of course!

Most of the red label tents are still not designed for high winds. I would consider the Kaitum2, but not much else.

The black label Nammatj tents have basically only two poles over the groundsheet, so they are not that strong in an off-axis wind. Yes, there are 3-pole versions, but the 3rd pole is for the bicycle.

The black label Tarra has a good design imho, but it weighs a ton: 4.3 kg. Ye gods!

The Keron3 has a good design too, but 4.2 kg!

Bear in mind that Hilleberg has to sell to the general public and has to make a profit. Gear for extreme conditions is not their main goal.

It is eminently possible to make a good reliable 2-man tunnel tent able to survive 100 kph winds for under 2 kg. It won’t be cheap though! And such a tent does need some experience in pitching, which you won’t find in affluent novices. Life is a compromise.

Cheers

[Stumphges]

I think high vs low use is a big factor in this discussion. For those camping low and able to shelter their tarp or tent behind windbreaks, flappy DCF tarps or DCF tents that don’t pitch taut, but are very light, are just fine, even great. For those who camp in exposed, windy places, a deformed DCF tent that no longer pitches taut because of that deformation is probably a no-go. Very different frames of reference.

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