Questions about EPIC

On a different, but related note. I have some Maxima ESD fabric. Here are the stats/ratings for it: http://www.burlingtonbarrier.com/Products/Static/maxima_esd.html

I'm rather confused about this material vs the ratings from the above link, because i can somewhat fairly easily suck air through and even blow through some. It seems slightly more breathable than my 2012 Houdini.

Yet, it lists the CFM as 1.21 when new. How is this possible, or are there different tests for CFM?

Same question for the hydrostatic head. It rates 850 mm for hh according to the "AATCC-127-1989" test for suter hh. Is this a different test/measurement than the one that Richard often refers to in his posts about the CFM and HH levels of various windjackets, etc?

Since this fabric is a bit lighter than the EPIC, but is pretty tough, durable, and apparently has a decent highly WR rating WITHOUT any DWR, why not work some silicone into the fibers and use this instead of the EPIC for the breathable front core panel for the poncho? Even if i don't do a good job of evenly applying the silicone to the fibers, even if it does wet out, because it's mostly thinnish polyester, it should dry really fast right?

WwBPLd? Any alternative suggestions to EPIC or Maxima for the breathable, front core panel that is reasonably priced? Thank you for any feedback.

> It seems to be a rather variable product as to CFM, HH and weights.
Correct. It is more of a process than a single product.
The very light synthetics make good jackets for SUB-zero use, like in the snow. But it is not good in scrub and not very good in rain. And EPIC on a cotton base is a failure.

Cheers

Hi Roger,

Thank you for the feedback. So, even if the HH is higher than i'm guesstimating (which is quite possible), say closer to 1100 or so, it will still be poor for the rain even though no zippers are involved, the shoulder area will be completely waterproof material, and the seams will be sealed?

Hi Justin

It's complicated. It is NOT a membrane coating.

You see, what the EPIC process does is to coat the fibres, so the fabric woven from those coated fibres has to rely on surface tension at the surface of the fibres to block the flow of water. That works fine up to the critical pressure where surface tension at the thread is not enough to block water from getting through the gaps between the threads. Once you reach that pressure, the water flows – in volume.

However, that means that the performance of the fabric depends totally on the surface tension parameter. On a fresh clean fibre surface, that can be 'high'. But the surface tension can be catastrophically degraded but a few things, like skin oils, plant juices from leaves, dirt, foods like butter, jam, sausage etc, and most anything else. The end result is that after a few days of use, the fabric is no longer 'waterproof' to any significant degree.

On natural fibres like cotton the surface coating can be abraded off by brushing against scrub or rock. That leaves you with a cotton surface, and we know how waterproof that is. A similar problem happens with synthetics, but the substrate is stronger.

I experimented with seam sealing and not sealing, and found that it did not really make any difference if you use a seam with several layers, like a full felled seam.

I have one EPIC jacket which I happily use for ski touring. It works well as long as the fabric surface stays below 0 C: it breathes well, blocks wind and sheds the snow. But note that I still carry my UL silnylon poncho for those days when it rains (a sad statement about our 'winter ski fields').

Cheers

Thank you for the in depth and detailed reply Roger. Yes, i had gathered similar from having read all i could on EPIC previously.

My thinking was though, that i will already have my windjacket with me, and if i combine that with the partial EPIC poncho, that even if it does catastrophically leak in the EPIC fabric areas, it most likely wouldn't also leak through the windshirt and then baselayer as well. So, i would put it on and keep it unzipped until i had any problems.

Sort of a Paramo like concept, but without the directional denier gradient fabric (pump liner).

In any case, i plan to beef up the HH of the Houdini a bit, by applying a very thin/diluted, light coating of silicone and rubbing it in. I'm doing this also so it works better with my Nikwax Analogy Pump liner. I'm mostly going to do this in the area where the backpack straps goes and some of the front core.

Hi Justin

> a very thin/diluted, light coating of silicone and rubbing it in. I'm doing this also
> so it works better with my Nikwax Analogy Pump liner.
Be VERY careful here. Given the inclusion of the word 'Nikwax' in the name of the liner, I would suspect that it may have a Nikwax treatment. That is wax-based, and is seriously incompatible with silicone treatment (or fluorocarbon treatment). There is some chance you may simply wreck the garment – or at least be dissatisfied with the result.

Cheers

No worries Roger…i'm well aware of that issue (in large part in thanks to some of your past posts)–perhaps i was being somewhat unclear earlier, but i wasn't talking about treating the Nikwax Analogy pump liner at all, but the Patagonia Houdini that i use as an outer shell over the N.A. pump liner.

2012 and prior Houdini's had an epic like treatment–hence they were encapsulated with silicone–a particularly light/thin coating, which is why it has a somewhat high CFM at 35, but somewhat low HH of 70 mm.

During some tests combining the Houdini with the Pump liner in heavier rain, i got somewhat wet, particularly in and through the shoulder areas. This could be because of either two reasons or a combo of reasons.

The seams on the Houdini in the shoulder area needed to be seam sealed, the Houdini does not have a high enough initial HH at 70 mm HH, or a combination of factors. In any case, i plan to seam seal the seams, as well as apply a bit more silicone to certain areas of the Houdini so that it becomes better for use with N.A. pump liner for colder rain.

I'm not sure i really need to do this, because i have a MYOG, sort of quarter/half poncho made out of silnylon, which is for use specifically with the Houdini and Pump liner combo. The half poncho is only long enough in the front, to go over the shoulders, but the back is full length to go over the pack. There is no hood attached. Being so simple, and so short, it's very light weight.

Anyways, back to the actual Poncho with an EPIC panel. While i will do some testing around my house first, i do "suspect" that combining a Houdini with the partial EPIC Poncho will be sufficient to keep me from getting wet even if the EPIC panel does start to really leak, because the water will not have enough pressure to also go through the Houdini and then baselayer. Again, i do plan to test it around home before i actually take it out backpacking. I also did testing around home with the Houdini, Pump liner combo first. I'm curious, open minded, and exploratory, but not impractical and stupid.

Hi Justin

> MYOG, sort of quarter/half poncho made out of silnylon, which is for use specifically
> with the Houdini and Pump liner combo. The half poncho is only long enough in the
> front, to go over the shoulders, but the back is full length to go over the pack.
A very interesting concept.
I have often wondered, while walking in pouring rain in warm weather, how such a half-poncho would go. So – keep us informed!

Cheers

"The half poncho is only long enough in the front, to go over the shoulders, but the back is full length to go over the pack."

You mean a cape?

"I have often wondered, while walking in pouring rain in warm weather, how such a half-poncho would go. So – keep us informed!"

Will do, but since i'm only using it with a Paramo like set up, unfortunately i will only using it during colder weather. The "pump liner" is just too warm to wear in anything above 7.2* C — 10* C roughly. And it won't be for quite awhile till i get to see those temps around here unfortunately.

While Paramo seems to be fairly well liked in England, Scotland, and Ireland, one of the somewhat common issues reported is water ingress near the backpack shoulder strap areas, probably from the extra weight/pressure of the straps on the shell and liner fabrics.

I figured, why not a partial poncho to deal with the issue, and also be a pack cover at the same time? At 3 to 4 oz (i don't remember the exact weight off hand right now), not much of a weight penalty.

To Justin: Cape? I guess, but i'm not familiar with capes. I wasn't basing it off anything i had previously seen, was just a made up concept in my odd head dealing with a pretty niche WPB gear system.

I looked up Capes. The ones i looked at, provide much more coverage than the MYOG silnylon pack/shoulder cover i made.

The difference between a cape and poncho seems to be that the cape is a bit more fitted and yes, can be a bit shorter on average. So i guess, in a sense, i could call the above a cape, but it's still rather different. I may put some pics of it up sometime. Since it's such a specialized piece of gear, i didn't think there would be much interest. Some folks here do use Paramo type WPB rain wear, but we definitely seem to be a minority.