By The Numbers Quickie: Meet my Shakedry Replacement-The Finetrack Photon WPB

Sounds like an interesting jacket. Thanks for the report!

• Does it have measurable air permeability?
• Which electrospun scored higher in MVTR?
• > “compatible with Grainger’s and Nikwax” <– Is that a credible claim (with reasonable effectiveness)? I thought that we needed to use FC on FC or wax on wax for maximum adhesion?
• > “Finetrack has developed a ventilation system that aligns airflow across multiple layers of clothing”. <– OK, so what is this fancy new ventilation system? All I see are torso zips closer to the center than traditional pit zips. I agree that is better placement for them (ventilation may not  be cut off by a pack’s shoulder straps). Is there any more to it than that?

I’m looking forward to hearing more about your field experience.

Hi Bill:

• I calculated .29 CFM/Ft2. This is through curve fitting, since my instrument does not officially measure below 1 CFM/Ft2. In my opinion, air permeability for WPB is irrelevant.  It is too low to have a tangible impact on user comfort under most usage conditions.
• The Neoshell fabric was style 6770, which achieved an MVTR of 3893.  It was an exceptionally lightweight fabric — around 100 gsm. HH was 9829, and air permeability was 1.19.  I am pretty sure you won’t find a commercial product made from that fabric. Its excellent MVTR performance was likely due to its very light face and liner fabrics.
• I specifically asked Finetrack what could be used for reproofing.  They provided the information I included.  I have not tried either product on the jacket they provided, so I have no further information.
• If you go here on their website, you can see a fuller explanation.  They have a five-layer clothing system.  The three outer layers will have these vents in the same positions. I have not tried this system, but I could see how it might be a sensible approach in the right conditions.

There’s nylon on the outside and polyester on the inside, both treated with DWR C6?

And a membrane in between?

That must be several ounces per square yard.  I wonder if you can buy just the fabric.

Interesting product

Finetrack Elemental layer must be just a thin polyester fabric?  I’ve been experimenting a bit with a hydrophobic base layer.  I noticed it doesn’t get wet when it’s raining, even if my rain jacket isn’t perfectly keeping water out.  I wonder if there is available any thin hydrophobic polyester fabric for MYOG.

That’s helpful about the NeoShell 6770. I see that it is the lightest 3 layer NeoShell or Power Shield Pro that Discovery Fabrics sells, so probably a good target for MYOG.

I know that we disagree about the value of air permeability in WPBs. I’m pretty sure that it matters, but maybe not in the obvious way. It’s not going to produce a ton of cooling in the way that a good windshirt does, but the fact that it allows SOME cooling makes it immediately superior (in comfort) to membranes that have none. I notice it when comparing ShakeDry to AscentShell (electrospun), which have very similar scores on your MVTR test.

It will be interesting to see whether you have similar experience with your Photon.

decoder ring for neoshell

https://cdn.shopify.com/s/files/1/0076/7318/4341/files/Neoshells_at_a_Glance_October_2022.pdf?v=1666200646

I got one of the no stretch neoshells and that made a really good rain jacket.  Pretty much stays dry

Hi Jerry, regarding your comments on the fabric construction. The Photon construction is typical for a three-layer WPB.  Some weight can be saved with a 2.5 or 2-layer construction, but the three-layer construction will provide better protection for the membrane and likely offer a better feel against bare skin.  I think the 15 denier nylon face fabric is an excellent trade-off between durability, weight, and MVTR.  It is possible to produce a lighter 3-layer membrane using 7-denier fabric, such as the Zpacks Vertice or EE Visp. However, you end up with a very fragile shell, a urethane membrane with substantially lower MVTR and an increased chance of failure due to hydrolysis.  Also, the 7 Denier 3 layer fabrics must use a restrained HH test. This places a metal grid over the test sample during the test. In my experience, a non-restrained test will cause the seven-denier fabric to rupture.  The HH result is not comparable to the results of a restrained test.

Regarding hydrophobic polyester.  It may exist, but I have gone to a lot of trouble to find and purchase fabrics that do not specifically claim to wick.  I have yet to find one that is actually hydrophobic.  You can make a wicking polyester hydrophobic by treating it with Nikwax.  I have found this to be very successful, but I have not put any shirts into regular use so I don’t know how often retreatment would be necessary.  Your other alternative would be to purchase Helly Hansen Lifa, which is Polypro.

I notice it when comparing ShakeDry to AscentShell (electrospun), which have very similar scores on your MVTR test.

And what exactly do you notice?

Thanks Stephen

I’ve been looking for a hydrophobuc polyester too.

Of course, polypropylene is hydrophobic.  I made a shirt with that.  Maybe, that fabric is uncomfortable against the skin.

When the WPB fails, the inside of the membrane gets wet.  If the inner fabric is hydrophobic, then the water stays on the inside surface of the WPB, and doesn’t get any clothing inside wet.

what exactly do you notice?

The electrospuns are slightly more comfortable while active. Not a lot, to be fair, but enough to persuade me that there is more to WPB comfort than any single lab measurement. Enough that I choose an electrospun when I know that the weather will be light.

I get a little condensation inside of ShakeDry while working that I don’t notice in AscentShell. They have nearly identical MVTR, so what is the difference? AscentShell is a hydrophilic membrane with very small air permeability, which ShakeDry is a hydrophobic membrane with essentially none. Polartec claims that the small amount of air permeability matters. My experience is consistent with that.

OTOH, in driving rain, I get a small amount of moisture inside the AscentShell that I don’t notice inside of ShakeDry or Outdry. I used to think it was condensation encouraged by the wet out face fabric, but there may also be a small amount of reverse-wicking possible in electrospuns. This effect may increase due to age and/or use.

Another observation is that my EE Visp is more comfortable in light weather than ShakeDry, even though the ShakeDry has superior MVTR.

There are confounding factors. My Visp has pit zips, my ShakeDry does not. Both my AscentShell and Visp fit better than my ShakeDry, which is narrow in the upper arms, inhibiting air flow.

These effects are subtle and we don’t have any way to measure them, which is why we haven’t discussed them (although I report them to Stephen as I notice them). I only say it here because Stephen brought it up. Otherwise, this is in the “we need more information and further field testing before we can come to confident conclusions” category.

Hi Woubier. I have had lots of use from Shakedry over the years and a few weeks of summer use for the Photon jacket.  In terms of MVTR, their test performance is similar, and I doubt I can perceive a difference in similar circumstances. I expect that the durability of the Photon will far exceed that of Shakedry.  I had pit zips in my Shakedry jackets (aftermarket).  I expect that the layers on my arms in the Photon will retain more moisture than the Shakedry due to the differences between pit zips and torso zips.  I was happy with Shakedry’s performance, but not Shakedry’s durability. I expect I will be happy with Photon’s performance and durability.

Stephen, it would be interesting to know how the DWR is performing in a long rain shower.

BTW, is there here a  study on how DWR influences the MVTR?

are there any studies about anything about DWR?

Hi Woubier and Jerry: I have two studies done by Philip Wayne Gibson with the Natick Soldier Research, Development, and Engineering.  Gibson, now retired, was a highly influential and prolific researcher in the field of military clothing.

Here is the conclusion from his 2005 study.  This study was done using C8 treatments, so results may vary for present day treatments.

Two of the water-repellent treatments had good durability to laundering. One treatment
had very poor durability, and lost all its water-repellent properties after 20 laundering
cycles. The Quarpel-treated control fabric performed better than any of the
experimental treatments. None of the water-repellent treatments significantly affected
the breathability, air flow resistance, or pore size of the BDU fabric.

It was found that the standard Battle Dress Uniform (BDU) fabric can be modified with
very effective water-repellent treatments. Soldiers’ duty and combat uniforms can be
made water-resistant and retain the same air permeability and “breathability” properties
as the untreated wicking fabric. Several questions arose as a result of this work. What
are the physiological implications of changing the BDU fabric from a wicking fabric to a
non-wicking fabric? Will the fabric still be comfortable when a soldier is sweating
heavily? Will liquid sweat now remain on the skin underneath the fabric, and is this bad
or good?
Following a separate field trial using combat uniforms with and without a DWR
treatment, it was found that these treatments decreased the comfort of the uniform in
hot environments. The differences between the comfort of the Control uniform and
those treated with the DWR treatments are probably not due to intrinsic differences in
the air permeability or the water vapor diffusion resistance (breathability) of the fabric. It
is more likely that the non-wicking behavior of the fabric was responsible for perceived
comfort differences, per comments from the field trial, and by analysis of
wicking/comfort properties contained in this report.
Some of the DWR treatments are available as coatings on just one side of the fabric.
The outer layer of the fabric can be made water-repellent, while the inner surface
retains its wicking characteristics. Based on comments from the field trial, and modeling
results, such asymmetric treatments would improve the comfort of DWR treatments on
military duty uniforms as compared to water-repellency on both sides of the fabric.

In this study, there is a statement that improper application of DWR can fill the fabric pores and impact fabric performance, but no examples are provided and this did not occur in any of his publications.

We don’t know if the comfort degradation found for the DWR treatment in the uniform garments under high effort, high humidity and high temperature conditions may be mitigated for our use purposes by choosing garment with far higher permeability and adding layers, such as Brynje that encourage evaporation from the skin.

One article can be downloaded here.  Another can be found here.

This is an area of research that is of interest to all of us and one I intend to pursue.  I have one relevant article ready for publication, but when this happens is out of my control. So, stay tuned.

Thanks, that will be interesting

Absolutely.

Because that was according to me the most important feature of Shakedry: the  PBS.

Here it would be something like this as a question: how is the MVTR affected on a garment with a classical construction vs a garment with a PBS and that after wet-out (of the classical garment as is supposed that a garment with a PBS doesn’t wet-out)?

Hi Bill,

AscentShell is a hydrophilic membrane with very small air permeability, which ShakeDry is a hydrophobic membrane with essentially none

do you have an AP-value for AscentShell because both are AP?

Hi, Woubeir. The air permeability of (2024) AscentShell is small. I generally assume between 0.5 and 1.5 CFM.

I don’t have any reason to think that greater air permeability matters in WPB garments. I’m pretty sure that “a little” is more comfortable than “none”, but we don’t have the resolution of test gear required to differentiate between them.

The tradeoff for the greater comfort is possibly less than perfect water resistance. It’s pretty clear that hydrostatic head doesn’t tell us the entire story there. The Motive AscentShell tested (or was estimated) at > 10,000 mm of H20, which sounds plenty waterproof. But if the pores stretch after repeated use and stuffing, and if the hydrophilic membrane wicks a little, then a small amount of water may ingress anyway (in heavy rain).

In heavy rain, my AscentShell feels soggy inside. My Outdry remains drier. But the AscentShell is more comfortable in light weather.

Tradeoffs: different membranes perform differently. Electrospun is great for light to moderate weather, while Outdry and Gore-Tex may be more waterproof in heavy weather.

What is “PBS”?

PBS = Permanent Beading Surface (so no separate application of a DWR needed)

Shakedry may have an AP ranging from 0,3 to 0,9 so maybe the difference you feel is not because of the AP but just another reason (still unknown to us).

I love it when scientists and their acolytes use abbreviations about technical materials only to conclude, “AP ranging from 0,3 to 0,9 so maybe the difference you feel is not because of the AP but just another reason (still unknown to us).”

I’m old and don’t have time to wait for the MTV to meet up with PBS  to bring me the hip hop News Hour while I’m wearing my leaky jacket in frigid temps.

“another reason still unknown to us” could be inscribed on every one of our tombstones.

That’s what I was thinking, public broadcasting system

Is polypropylene a permanent beading surface?

Maybe they could make the outer layers polypropylene

Jerry: Check this out.

Is polypropylene a permanent beading surface?

No. The surface energy is too high with 30.

You need a surface energy of 20 or so,

Any idea how that polypropylene jacket would work in the rain Stephen?

I looked at https://www.tstar.com/blog/bid/33845/surface-energy-of-plastics

Fluorinated plastics are 20 but they’re unhealthful.  Rubber and Polydimethyl siloxane (which I think is silicone) are good but you can’t make clothes out of them..  Polyethylene and polypropylene are the best available.

In those links Stephen posted, they said DWR can wash out after laundering.  What about the DWR getting worse after exposure to water?  It seems like some DWR beads up initially, but after an hour in the rain it quits beading up, it wets out.  Other DWR continues to bead up after a long exposure to the rain.  Am I just imagining this?  Is this something you can test?

Polypropylene seems to maintain beading indefinitely.

Another thing that happens is I had a DWR jacket that wetted out easily, so I washed it, and applied DWR treatment and the DWR performed much better.  I’ve read that the DWR can get dirty over time which reduces effectiveness.

Jerry, what do you mean with ‘other DWR’?