Uber Bivy Top Material Analysis Mystery

Hi  my email is donandrews41@yahoo.com.au

resurrecting a 2015 thread.  Those people probably aren’t reading this.

I’ve been playing with polypropylene recently.  Maybe this idea infected my brain and slowly grew over 10 years, kind of like a brain worm, only it didn’t die, just continued growing : )

I got something like this from the fabric store.  And then a heavier version from amazon.  I think it’s intended use is the bottom of upholstered furniture.  Spun bonded non woven polypropylene.  I bought some foam and they rolled it up and then put some of this polypropylene over it to fasten it – it’s cheap, a packaging material like a plastic bag or paper.

I made a shirt.  It works okay as a base layer.  It seemed to be a little scratchy.

When I wore a WPB jacket in the rain, the inside got wet (condensation?) as happens with WPB sometimes.  When I had a polypropylene shirt inside, the water stayed on the inside surface of the WPB.  Hmmm… maybe there’s a strategy here for staying dry in the rain.  This has some commonality with Paramo fabric.  It’s the rainy season again – I can continue this experiment.

I made a pair of gaiters.  This worked very well – walking through wet brush my socks and feet stayed dry.  Until I brushed against a stick.  It formed a long tear.  The fibers in the fabric are very small so easily tear.  Any rip will easily propagate.  Maybe I need some polypropylene woven fabric with larger fibers.

I see polyproylene fabric intended for a weed barrier or geotex fabric.  Maybe that won’t rip so easily.  That is woven, larger fibers.

I could make a jacket out of the spun bonded polypropylene fabric but I’m afraid it would rip.

There are two possible uses – on the outside, it will repel rain. Or on the inside, it will keep water from flowing in.

I’ve had an experiment going for 6 months.  I have pockets inside my WPB jacket.  Occasionally, when water collects on the inside of the WPB, it soaks into the pockets and gets the contents wet.  So I put a polypropylene piece between the pocket and the WPB.  The pocket on the other side has no polypropylene.  I am now waiting for a case where the polypropylene pocket stays dry, but the non polypropylene pocket gets wet.

I also have a frost protection fabric for my garden.  It’s polypropylene, lighter weight, spun bonded, but without the little dots where the fibers are welded together.  I can just pull that apart.  It might work for lining the pockets, nothing structural though.

I looked into this thread last year but didn’t find enough to write about:

ProVent is a little different than garden fabrics and the stuff from fabric stores. It is legitimately tech stuff, although ProVent 10,000 has been mostly replaced by newer versions (ProVent BC and ProVent Plus). I have a suit made out of ProVent 10k. It’s the same idea as a Tyvek suit, but polypropylene instead of polyethylene, and with different characteristics as Richard measured.

The Relative Cost and Relative Performance charts show the main story here: This is a budget fabric, not a high-performance fabric. However, it appears to be sufficiently performant for a bivy. David Miles (the Uber Bivy creator) developed the Uber Bivy for SAR work and seems to have happy customers.

David used to sell the fabric, but I don’t think he does that anymore. Kappler sells through distributors.

ProVent might actually be one of the better budget waterproof-and-slightly-breathable fabrics, but it won’t outperform NeoShell or Power Shield Pro (or other WPBs) for applications where higher MVTR is desired. It may not be strong enough for a tent, but it appears to be fine for a bivy.

Lawn and clothing shop polypropylene fabrics can be more breathable, but not as waterproof. Tradeoffs. They might be better for garments such as wind shells.

Kappler appears to only sell clothing, not fabric

Looking at their pictures of clothing, it appears to be spun bonded very thin fibers with dots that are about 1mm diameter where the fibers are melted together,  spaced several mm apart.  That’s like the upholstery dust cover fabric I got.

I wonder if it would survive brushing against a stick and not ripping

MLD is offering their WPB soul bivies with ProVent UL – am not sure if it the same material that is being discussed here

Just curious if that could be a source of prevent

Provent ul is the name of the bivy.  It uses eVent wpb fabric

MLD doesn’t tell us anything about “ProVent UL”, other than it is what they call the new fabric. MLD bivies are top quality, Kappler ProVent is budget-oriented.

Elsewhere MLD says that eVent is no longer available. I suspect the mention of it is just an old artifact that was missed when the page was updated.

My guess is that the two “ProVents” are unrelated.

@Ron_Bell will know for sure.

I meant to say provent, not prevent, damn spell checkers : )

Ahhh… somewhere I read eVent, must be old

it says that provent UL is “2.5 layer PU Laminate WPB” so yeah, that must be unrealted to provent from Kappler

it also says the DWR doesn’t contain PFAS.  I wonder what they use.  If they used polypropylene then maybe it doesn’t need any DWR?

Hi Jerry and Bill, I am testing a hooped bivy that I have just finished making.  The bottom is 1 ounce Dinema and the top is 60g per square meter polypropylene?  which I bought by the meter at HQ Fabrics.  If you google  HQ Fabrics non-woven white, Ali Xpress it should come up. It is cheap at $4.36AU a meter x 160cm wide.  Another one by the meter you will find if you google EPTEE/PTFE Waterproof breathable membrane Ali Xpress.  Is this what David Miles uses?

Sorry that should read Dyneema, and also AliExpress.

thanks

polypropylene is available on amazon from multiple vendors.  Of various weights including 60 g/m2.

is yours spun bonded with little 1mm spots where the fibers are bonded together, spaced a few mm apart.  Very small denier fibers?

like I said, I made gaiters out of it but they ripped easily.  A jacket doesn’t get as abused as gaiters, but I fear it would also rip.

that would be interesting to see how it works as a bivy.  I don’t think it’s ripability would be a problem for that application

what happens when it rains is the question.  I would be very interested to hear your results.  and what happens if you get dew or frost on it.

Jerry, the HQ Etsy is what I used on  my bivy.  Has no  holes.  I compared it to Tyvek Homewrap and Tyvek Softwrap.  It is harder to tear than Tyvek but easier to puncture.  It did not wet out in 2 days of testing and neither did the Tyvek.  I have not had  a chance to test it in rain.

oops

Don: To answer your question, no, none of that is what David Miles uses. He said that he uses Kappler ProVent 10,000 most recently, and ProVent 7,000 previously. Kappler now sells ProVent Plus, but we don’t have any performance information about it. As Richard Nisley tested, ProVent is waterproof and moderately breathable (although not as breathable as higher-quality WPB fabrics such as NeoShell, Power Shield Pro, or AirCore).

Kappler sells through distribution. As an individual, it will take some effort on your part to buy it. There may be minimum quantities, and Kappler doesn’t actually say that they sell the fabric alone. We don’t know how David Miles buys his.

I have a ProVent 10k suit. It’s not the same as common polypropylene fabrics, but it is still polypropylene.

I have used common garden non-woven polypropylene fabric as a windbreaker. The stuff I chose is moderately air permeable and not waterproof, but it does shed light rain. Polypropylene is very slippery, so it acts as though it has DWR, but the effect is built-in. Permanent.

Sure, experiment with your bivy, and test it in various conditions. I don’t think anyone can predict the performance of fabrics you find on AliExpress, but you may find a great fabric for your purposes with some experimentation.