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Jason Delso
(zencarver) - MLife

Locale: DFW
Re: Goinmg beyond the Standard on 04/05/2011 09:51:27 MDT Print View

"The interesting case is where a fabric (often with a silicone coating) allows a few drops to become visible at a moderately low pressure, but those drops do not grow in size despite a significant pressure increase. I have seen quite a few of those. What is happening there? How do you grade such fabrics?"

I don't know what's happening there, but I think that's suitable for a shelter (for me). This whole thing is fascinating, and I'm eager to see where it all goes.

I know that, "What is the hydrostatic head of material [A, B, C,..]?" isn't the ultimate question here. I think it's actually, "What is the suitability of material [A, B, C,..] in shelter construction for use in conditions [a, b, c,..]?" The journey to the answer is fascinating, though.

Lance Marshall
(Lancem) - F - MLife

Locale: Oregon
Thru-Hiker Shield silnylon on 10/04/2011 13:23:13 MDT Print View

I tested two pieces of Thru-hiker’s Shield silnylon today and was impressed by the results. In both tests, the fabric’s resistance to water penetration was greater than could be measured with my DIY HH tester.

In the first test, about 2500mm water (184mm Hg) was reached before the fabric was pushed out of the seal. No bubbles appeared. In the second test, a single bubble appeared at about 2284mm water (168mm Hg). I stopped the test at 3358mm water (247mm Hg). No additional bubbles had appeared.

In contrast, I tested a piece of silnylon from another source (I didn’t track which of several sources I might have purchased it from) and it failed below 400mm water.

First sample at approximately 2257mm water (166mm Hg).
Shield silnylon hh pic 1

First sample at approximately 2500mm water (184mm Hg). Note the bulge in upper right where the fabric is about to be pushed out of the seal. Stopped test here.
Shield silnylon hh pic 2


Second sample at approximately 2284mm water (168mm Hg). First bubble has appeared.
Shield silnylon hh pic 3

Second sample at approximately 3358mm water (247mm Hg). First bubble is larger. No additional bubbles have appeared. Note the bulge at left where the fabric is about to be pushed out of the seal. Stopped test here.
Shield silnylon hh pic 4

Test of silnylon from unidentified source, at 400mm water.
unknown silnylon hh test 1

Of course all the caveats from the original thread apply here as well. Yada, yada

Hope this is useful.

Edited by Lancem on 10/04/2011 13:49:15 MDT.

Samuel C. Farrington
(scfhome) - M

Locale: Chocorua NH, USA
DIY HH Tester on 10/04/2011 21:22:49 MDT Print View

Wow. Thank you very much!

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Shield Silnylon +1 on 10/04/2011 21:42:31 MDT Print View

Lance,

Five months ago I had similar results which I posted to the forum at http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=47311

After that post, Roger Caffin, Paul Nanian (Thru-hiker), and I jointly collaborated on additional Shield testing. I added a coarse mesh screen to eliminate damage caused by slipping in my tester. After this fix, Shield silnylon pegged my low pressure hydrostatic head tester at 3,515 mm H2O for both its virgin test and three protocol B type aging cycles. It matched the performance of the .18 Mylar Cuben (CTF3) fabrics for long term performance.

It is currently the best silnylon product available but, we know how it can be improved. My micrographs show that the thread count is less than what is easily achievable for that denier.

Edited by richard295 on 10/04/2011 23:50:31 MDT.

Lance Marshall
(Lancem) - F - MLife

Locale: Oregon
Re: Shield Silnylon +1 on 10/05/2011 14:43:10 MDT Print View

Richard, thanks for the link. I missed it back in May. Also, thanks for the idea of using a screen to back up material when testing.

-Lance

Richard Tie
(RichieT) - F
Mechanical performance of Shield Sil Nylon? on 03/04/2012 08:28:15 MST Print View

Hi all you knowledgeable people,

thanks so much for this insightful thread, I have learned a lot already.

I am currently trying to decide on a material for my next project, and would like to ask you:

Does the lower weave density of Shield mean it is mechanically weaker than other competing products? If so, how much? Meaning, is the difference significant in real life?

I feel I have to outweigh through-misting, general waterproofness, and the longevity of the waterproofness (in which Shield seems to perform best) against mechanical properties (which I'm not yet quite sure about regarding Shield).

Another question I have been thinking about is: If rip stop nylon has the tendency to leak along the stronger threads (if I'm getting one of the earlier posts in this thread right), how strong a case would you say that is for using non rip stop nylon instead? I assume the loss in rip stopping ability is too high a price to pay, but would like to hear what you think about it since you know a lot more than me obviously.

If you can shed some light on these questions, I would be grateful...

Richie

Edited by RichieT on 03/04/2012 08:32:05 MST.

Richard Nisley
(richard295) - M

Locale: San Francisco Bay Area
Re: Mechanical performance of Shield Sil Nylon? on 03/04/2012 09:49:32 MST Print View

Richie,

I didn't measure the mechanical performance of shield but, comparing it to the weave density of most other silnylons via micrograph, it is similar. Although Shield was the best silnylon that I had tested to date, the same coating, with a higher density weave would yield an even better product. I assumed that like the competition in the M90, M55, and M50 market segments, even better alternatives will be available at some point in the near future.

Edited by richard295 on 03/04/2012 15:30:07 MST.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Mechanical performance of Shield Sil Nylon? on 03/04/2012 11:01:13 MST Print View

That would be really nice if they put silicone on one of those lighter nylons

The 30d of standard silnylon is way stronger than necesary. For a regular tarp in normal conditions I don't think it comes anywhere near tearing.

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Mechanical performance of Shield Sil Nylon? on 03/04/2012 14:12:41 MST Print View

> If rip stop nylon has the tendency to leak along the stronger threads, how strong a case
> would you say that is for using non rip stop nylon instead? I assume the loss in rip stopping
> ability is too high a price to pay,
First of all, I will claim straight out that the use of ripstop fabric for UL gear is totally UNNECESSARY. There have been very, VERY few reports of fabric failure in the field with even the lightest of fabrics. If you get into a situation where the fabric is going to rip, I really don't believe that the ripstop threads will save you. OK, let's leave out those cases where the gear failure is due to sheer bumbling 'user error'.

So why does everyone use ripstop? Two reasons: marketing spin and inertia. OK, maybe a third reason: ignorance due to a lack of testing. The market asks for ripstop so the coating companies supply ripstop. It's time we changed that.

So, if you can get a plain-weave fabric instead with a similar coating, go for it (after HH testing of course).

Cheers

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Shield Silnylon +1 on 03/04/2012 14:14:35 MST Print View

> After that post, Roger Caffin, Paul Nanian (Thru-hiker), and I jointly collaborated on
> additional Shield testing.

This project is not dead; it's just waiting in the queue to recover from my hard disk crash and loss of data.

Cheers

Lyan Jordan
(redmonk)

Locale: Greater Yellowstone Ecosystem
DIY HH Tester on 03/04/2012 15:11:47 MST Print View

I'll take the fabric that adds protection against user error, thank you very much. Tired people will make mistakes.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: DIY HH Tester on 03/04/2012 16:18:47 MST Print View

"I'll take the fabric that adds protection against user error, thank you very much. Tired people will make mistakes."

Yeah, you want enough margin to allow for errors you might make, but you don't want extra margin, because it's too heavy.

If you made a tent out of 4 ounce nylon you could dive into the tent and have your dog do this also without hurting the tent

You could design it so the tent stakes would pull out just before the fabric would rip, or something like that, and it would be even better engineered

What works for one person might not work for another person...

Richard Tie
(RichieT) - F
Upsides and downsides on 03/04/2012 18:33:24 MST Print View

Hi again,

Roger, I agree with you - for ultralight use. Our situation is slightly different from that scenario though, so I'm not convinced just yet unless there are hard numbers somewhere. If there aren't, I may have to just go with rip-stop for this project and application.

This is why:

"If you made a tent out of 4 ounce nylon you could dive into the tent and have your dog do this also without hurting the tent"

Well, that's kind of what our shelter will have to live with sometimes. In our case, it's not a dog but two very energetic preschool children. Normally they are really good with gear, but when everyone is tired or over excited, stuff happens. The same goes for those rare but hectic moments where we pitch in horizontal rain-thunderstorms and the like, where it will be us, the parents, not beeing super careful with the gear.

In addition, we occasionally have very high winds, to the point where walking becomes difficult for an adult.

From experience, I can clearly say that the Ray-Way sil-nylon is up to all that, as long as it is sewn right. So I'm pretty sure 4 ounce nylon is really not needed even for that. But I have a feeling I would prefer to keep the rip stop in the sil-nylon for our application.

We always go light, but we are not on an ultralight mission, and top priority is gear that requires minimum attention, time and energy from us while out there, while providing a high level of reliability even under less than ideal use - because that does happen in real life, especially with children and on trips that go beyond a simple overnighter.

An action that is tough on gear that you could call a "bumbling user error" on a nice sunny day very quickly becomes an action that is extremely hard to avoid under seriously tough conditions, and that's exactly when I can not afford to have a shelter fail on us.

I have the impression that sometimes, people who go ultralight tend to not think about what actually happens when for example their shelter goes to shreds in a "totally unexpected" blizzard. Of course, there are places on earth where conditions are more predictable, and there are those where that is less the case. Still, stuff happens, and I really don't mind whether I carry 12 or 15 kilograms of gear. Each to their own, of course.

On very long trips I found out that I can happily walk with up to 35 kilograms, and that's not for bragging, quite the opposite: I weigh 70 kilograms myself and am neither a super fit athlete nor a couch potatoe - I think most people can carry a lot more than they think. I am in no way debating that less weight is better for many reasons, and even increases safety on trips as well - that's absolutely correct! But there is a limit to that, and if you go below that, the problems that that can cause in those rare but very tough situations are not worth saving yet another few hundred grams.

Just something to think about, not telling anyone how to go by any means, and I'm very thankful for the ultralight movement because it is continuously contributing to making gear and gear systems better.

Now, back to choosing a fabric... :-)

Happy trails!

Richie

Roger Caffin
(rcaffin) - BPL Staff - MLife

Locale: Wollemi & Kosciusko NPs, Europe
Re: Upsides and downsides on 03/04/2012 18:42:11 MST Print View

Hi Ricahrd

> I have the impression that sometimes, people who go ultralight tend to not think about what
> actually happens when for example their shelter goes to shreds in a "totally unexpected" blizzard.
I think that might be a bit off the mark here. You should consider subscribing and reading some of our articles, including "When Things Go Wrong" (winter, snow, winds over 100 kph) and "Storm Resistance of Ultralight Shelters: Part 1, Introduction " (self explanatory).

Cheers

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: Re: Upsides and downsides on 03/04/2012 20:03:13 MST Print View

silnylon can withstand blizzard

dogs and kids and don't mind extra weight? might be better off with 4 oz nylon

Richard Tie
(RichieT) - F
Re: Re: Re: Upsides and downsides on 03/04/2012 22:13:19 MST Print View

Roger, I'm sorry if you or anyone else felt offended.

I wasn't referring to BPL or anyone here in the forums, nor was I criticising the ultralight approach in general; far from it. Rather, I was referring to some people we have met offline in the mountains, who were so lightly equipped that they most definitely would not have been able to look after themselves should the weather have turned.

I know that most people who go ultralight think very carefully about how they do things and what they take. I still stand by my view though that some people do develop a too single minded approach in that regard, ignoring the possible consequences of bad choices.

That happens with everything; there are always some people who do things recklessly, be it driving a car or going ultralight. I just wanted to point out that because going ultralight is such a desirable goal, it can happen that one forgets to keep other important things balanced.

Another things is that the more you push the concept of ultralight, the more you rely on not making any mistakes - and people frequently make mistakes, no matter how skilled and knowledgeable they are, especially in tough situation. We are human. It happens. That's why I like to allow a little room for error, that's all.

Cheers,

Richie

Edited by RichieT on 03/04/2012 22:29:37 MST.

Richard Tie
(RichieT) - F
Re: Re: Re: Re: Upsides and downsides on 03/04/2012 22:15:25 MST Print View

If you would like to have a piece of Ray Jardine's sil-nylon for testing, let me know, I can mail you a bit.

Would be curious myself how it compares to Shield, for example, especially since I have had great experiences with Ray's material myself (more about that here: http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=60573).

Richie

Richard Tie
(RichieT) - F
Re: Re: Re: Upsides and downsides on 03/04/2012 22:24:15 MST Print View

Jerry, I know, from own experience :-)

Although we don't want to go ultralight, 4 oz is a little too heavy for us.

We don't have dogs, and from experience I can say that Ray's (probably around 2.2 oz) sil-nylon is tough enough for our kids.

The only thing where a wee little more would be good is regarding stretching in very high winds (also see the other thread, see link in my previous post).

I'm thinking maybe around 2.5 oz or so would be ideal for my taste, but of course it depends on a lot more than just that number.

Richie

Samuel C. Farrington
(scfhome) - M

Locale: Chocorua NH, USA
what fabric on 03/05/2012 21:31:21 MST Print View

Richard,
Ray's site states that his silnylon is in the same weight range as other 30 D silnylons - 1.3-1.4oz. He claims to have a proprietary treatment to make it more waterproof, but whatever the merits of that, it would not increase its strength.

It sounds like you have run into gram weenies who are placing themselves at risk.
Roger is not even remotely one of those. Just take a look at his tents on the Bushwalking.org.au FAQ site and do read "When Things Go Wrong," on this one.

If you want heavier canopy materials, look at the material used by Appy Trails, or the material in the Chinook tarps. The latter is coated polyester that won't sag like silnylon. The former - do not recall. But polyesters tend to be less strong than nylons. And if you want to go broke, there are sturdier cubens in the 1-2 oz range, a number of which are sold in smaller quantities by Zpacks.

My only gripe is that none of the silnylons sold by Ray Jardine or Thru-Hiker are in the earth-tone - green range. Lightheart Gear uses a better quality silnylon in its imports, but that is not the one it sells as yardgoods. Most of the silnylons currently available are much inferior as far as water proofing goes. Read Richard's tests on this site.

Roger's posts suggest that current EPA regs in the USA have required firms here to discontinue the more WP silnylon treatments. Whatever the reason, the HH testers don't lie (although they could be mistaken, as any scientific measurement can be). I think that if you buy the cheap stuff, you will eventually be disappointed. It will sag a lot, and its waterproofness will diminish fairly quickly with use. It will probably tear more easily also.