HH performance of Ripstop by the Roll 1.1 oz Silpoly, Khaki

Is it just me or do those HH numbers seem WAY high. No slight intended, but it would be nice to see if the results could be duplicated by another lab (or two). I think any reputable scientist would invite that, and it’s really what scientific method requires in order to automatically be 100% believed. Call me anal, but wanting another look shouldn’t bruise any egos. Goes with the territory and it would provide fairness to RSBTR’s competitors.

I agree that the HH figures are creeping upwards. However, this is not impossible.
If you make the weave tighter (more threads per inch), the gaps get smaller and the HH can go up.
If you improve the siloxane polymer to be stronger, then it can resist water pressure more.
If you shrink or better still get rid of the ‘ripstop’ threads, the fabric become more uniform for coating and the known HH weaknesses at the ripstop threads reduce or go away.

This is all theory. If RSBTR wants to send me samples I can test them on my HH tester and report the results.
https://backpackinglight.com/diy-hydrostatic-pressure-test/
Please note: I have no connection to RSBTR.

Cheers

In a follow up post above, I indicated I would be following up on the discrepancy between my measurements and RSBTR.  This is where this stands:

I have received a communication from RSBTR that indicates their fabric is tested according to AATCC 127.  This test is similar to ISO 811 which I use as guidance.  AATCC 127 of course requires the submission of a written test report which documents what was tested, what the test results were, the test conditions and what instrument was used.  I am going to ask them to provide that to me so perhaps we can better understand where their posted numbers come from.  This is kind of strange:  I am saying their product performs much better than they do.  Clearly, their product sales should improve if they can demonstrate improved HH performance, at least to members of BPL who seem pretty excited by the higher HH I measured.

On my end, I have undertaken a review of each component of my test system that could cause a higher reading.  So far, I have identified one issue.  I have ordered four fabric samples  so I can complete measurements on several fabrics and properly document the issue I have identified.  The fabric manufacturers have published specs for each fabric, so I can see how they compare.  I have also been in contact with several 3rd party labs to obtain pricing on getting a fabric sample tested to see how it compares with my results.  I have received pricing from one lab who claims their test instrument measures up to 1000mm, which is shockingly low for today’s fabrics and of no use for the current issue.

Geoff-I can run an ageing test.  When I get the fabric samples I ordered, one of which is the same fabric, I will do that.

Some of you may wish to look at the recent article published by Roger Caffin describing his do it yourself tester.  One of his tests is particularly relevant because he measured performance for one fabric that was much higher than the published HH specification for the fabric.  I have tested the same fabric previously and, at the time, sent an email to the company and received a response back that I still do not understand and did not pursue farther.

I will post again on this when I have some new information.

Life is never simple, especially in the more woolly areas like HH.
Suppose you had a roll of fabric, cut off a strip from the end, and had 4 HH tests done across the strip. Your results are (say) 2,000 mm, 2100 mm, 2,200 mm and 1,900 mm. Trust me, your results WILL have such scatter.

Now, how do you advertise this fabric? Do you take the average and claim 2050 mm? But two of your tests gave values below this. Do you take the highest value (2,200 mm) or the lowest value (1,900)?

Or do you play it safe and claim 1,500 mm, with reasonable confidence that no customer will ever find a value lower than that? In the long term, if you survive financially, you might get a good rep from this.

Cheers

Geoff, re:  “Sadly, for those of us who’d like to order some, they seem to be out of pretty much all the usable colours. Hopefully they will be able to sort this soon, as it seems to be one of their most popular products…”

I’ve also passed up ordering some RBTR products because of color limitations, either from selling out, or just few choices.   One example is their 6.6 silnylon. 1.3 osy with coating.  When this first came on the site, they also offered a charcoal color, and I bought some for a tent floor, because I don’t want to carry a groundcloth, and because the fabric is much more durable than other nylons or polyesters of similar weight.  Now they offer it only in white, and have done so for some time.   It’s nice to see what’s floating around the tent floor, but not when the white gets dirty after a while.  Light earth colors would be great, however.

Could offer many other examples, but believe it is a matter of what is available on the wholesale market, and for how much.  They are in business, and have to keep the bottom line in mind.  For the fabric that is the subject of this thread, and for many others, they do have a feature that allows us to request a color that is sold out.   So far, that has not helped.

There are some European companies that offer the same or similar products:  Adventure Expert, and Shelby Outdoor; and sometimes they source colors not available in the US.  I’ve ordered from both, so far with no problems, although delivery time and costs from Europe are higher. More than I can say for some umpty billion dollar companies in the US.

I understand Monte’s concern.  But we are fortunate to have had a few people on BPL who have been willing to test fabrics.  The fabrics come from who knows where, and might vary on the same swatch, not to mention other runs.  The suppliers provide a bottom line, and I think that is the most we can expect, especially in the current circumstances when it sometimes helps me to recall “Now Be Thankful,” a moving song by Richard Thompson and Dave Swarbrick.

The Extrem Textil 20D nylon was tested by Stephen and posted on BPL, and later Roger did so also.  Roger came in around 5K mm HH, and Stephen a thousand or more mm higher.  Both were way above the waterproof standard of 1500mm HH, and there could be many possible reasons for the difference.  As MYOGers, I don’t think precision is likely to be our strong suit.

Agree with Geoff about the simulated aging, something that Richard often did.  Sometimes the HH after simulated aging fell from slightly above 3000mm to below 1000mm, a sign that a fabric that seemed AOK for a water resistant tent, was not.

Roger, I would be glad to send you samples of the l.l oz silpoly from RBTR in khaki and/or lime green.  Please let me know what dimensions you would need, and we’ll hope the US and international postal services are still working.  Thanks.

Anything over 8″ square is testable.

Cheers

OK, Roger.  Will mail a square out to you this week.

RBTR’s silpoly selection has been dwindling for some time – at least since May, when I wanted to buy some Green Tea silpoly. I am guessing they are having trouble sourcing their fabric due to COVID. It has to be one of their top-selling fabrics.

“For the fabric that is the subject of this thread, and for many others, they do have a feature that allows us to request a color that is sold out.   So far, that has not helped.”

But it has now.  Just received an email notice and ordered  1.1 oz silpoly in green tea color.

Hard to believe over three months as passed.  I said I would look into concerns about whether my readings are high.  I will post a report on this when done.  It turns out they are.  The standards require a test surface of 100 square cm.  The manufacturer of my device claims in their specifications that it meets the 100 square cm test surface requirement.  It turns out, it is way smaller!  My subsequent testing demonstrates that as test surface area increases,  the pressure at which failure occurs decreases.   I have had a machine shop create a new reservoir and clamping assembly that meets the 100 square cm requirement. I have retested and proved the relationship between test surface area and failure pressure.  The only problem I have to overcome is that it leaks over 20000mm pressure.  I should solve this problem before long and will then document all the interesting things I learned about  HH testing and the HH testing capability offered by independent labs. More on this soon.

Hi Stephen,

Roger Caffin has informed me that he uses a very small test surface.  You can check his article about his tester on BPL:  https://backpackinglight.com/diy-hydrostatic-pressure-test/

Hi Sam:

I have read it.  Roger’s readings, like the ones that I did so far, should be repeatable and can be used to compare the performance of different fabrics.  However, the numbers will be higher than if tested on an instrument that meets AATCC 127 or ISO 811 requirements. When I write up my test results, before and after, this will be very clear in the data.

My numbers might be high compared to ISO etc? Quite possible. Mind you, with the bigger test ring the bulges may be spectacular! Big forces too.

What has been far more interesting to me is the way the HHs have gone up over the years. That has been cheering.

Cheers