Was tested on the CT, though we only had about 4 days of more serious rain (there were other days of light drizzle, but i don’t count that). Pics will be forthcoming.
First part is a simple poncho with no hood. The entire front of the poncho is WPB combo fabric. I sourced some of the old UL silnylon from Dutchware that didn’t test very well as to HH by R.N. (around an average of around 750mm if i’m remember correctly). To further increase air permeability, i folded it up, and ran it through my sewing machine while it was non threaded.
That’s the outer material, which won’t ever require adding more DWR (well, at least not for a very long time most likely). To that i sewed “Kite” or 1443R Tyvek that someone from BPL very kindly sent to me for free.
One batch of this type of Tyvek was tested by R.N. to have a CFM of around 6 and aged HH of around 1000 mm (a little under i believe). Since it’s made out of polyethylene, it’s naturally highly hydrophobic and won’t ever require a “DWR”, but will need to be occasionally rinsed and more rarely washed (same with the silnylon fabric). Apparently this sort of Tyvek (and others) are variable as to exact specs (which is unfortunate).
I did not sew the two fabrics together at the bottom. The idea was that any rain that got through the first layer of perforated UL silnylon, could escape through the bottom. I made the silnylon outer layer slightly longer so the weaker Tyvek inner would be less likely damaged. The silnylon outer in general protects the much less durable Tyvek from punctures, outer abrasion, UV damage, etc. It also dramatically lessens the force of the rain drops so that the Tyvek will be much less likely to be penetrated.
To this front WPB combo fabric, i sewed RSBTR’s Membrane Silpoly for the back, pack covering part. I also attached some 1/16th shock cord and micro cord locks, so i can cinch up the sides. When more cinched up, there is enough excess shock cord, that i can tie it across my front, which keeps the front stabilized and from flapping in higher winds. Total weight of poncho is 4.2 ounces.
Ok, so no hood, how do i protect my head? I took a wide brimmed nylon Sun hat, sewed some soft sided velcro onto it (4 strips–1 on each side, 1/front, 1/back). I took a piece of EPIC fabric and sewed matching velcro onto it. It’s a Sun hat when i need it, and a rain hat when i need it, and at very little weight gain. The other nice thing about it is that it allows me to vent my neck/chest better since there’s more coverage. It decrease wind drag too.
Actual experience/testing: Literally the most breathable and comfortable rain gear i’ve ever tried. The only cons are those that are common to ponchos–sometimes there was some water ingress through the side, arm hole areas, but a WR wind jacket is recommended for heavier rain to be used in combo anyways (can keep the front mostly unzipped to increase air permeability). Otherwise, kept me dry from both outside rain and internal moisture buildup and at 4.2 oz, hard to complain, though if you factor in the piece of EPIC that goes over the Sun hat, weight probably goes up to almost 5 oz.
Also, we experienced some hail on the trail, and the hat plus fabric on top, helped to cushion my head a little more than just a straight hood would have.
The beauty of the overall system is it’s combo of adaptability, lightweight, function, high breathability, and above all–no f’ing temporary “D”WR’s to mess with or compromise the breathability.
There is probably no rain gear system on the market, except umbrellas, that provide as much overall breathablity, while having serious rain protection. Didn’t cost much to make either, and was pretty easy/simple to construct. I probably will swap out the EPIC fabric for the hat, for the same combo WPB fabric i used for the front of the poncho. I could see my head eventually getting wet in a long, hard sustained rain, though the EPIC fabric is pretty highly WR and the nylon hat underneath is innately somewhat hydrophobic.
I’m looking forward to more testing/use in the more humid S.E. where i live, because i feel that is where it will shine even more.










