by George Groot
In the late 1990s I turned in my old olive drab canvas sleeping bag and received a new issue of the Army Modular Sleep System (MSS), which consists of a lightweight summer sleeping bag, a heavier winter bag, and a Gore-tex fabric bivouac (aka bivy) cover. All three items snap together to make a single unit, but you can mix and match the bags as needed; one time I even slept in just the bivy cover during a Texas summer. That old MSS set in woodland camo was turned in years ago as the Army transitioned to the “Let's invade the Moon!” Universal Camouflage Pattern (UCP) before transitioning to the current Operational Camouflage Pattern that looks very similar to MultiCam.
On the surplus market you can find all
the parts for an MSS in both woodland and UCP camouflage patters, but
for this article I just want to talk about the bivy cover. Generally this is the most
expensive part of the MSS since it is made of Gore-Tex, which is
generally a dandy fabric for the great outdoors. However -- and I’ve
learned this the hard way -- Gore-Tex does not retain its waterproof
capability after being run through the washer/dryer in order to get
your gear clean for Central Issue Facility (CIF) turn-in. This means
that a lot of the bivy covers on the surplus market aren’t very
waterproof at all.
However, that doesn’t mean they can’t
be made useful again. I recently purchased two UCP pattern bivy
covers for my sons, and paired them with a Walmart-brand mummy bag
for camping with their Trail Life troop. However, my eldest son woke up in a puddle of water while still inside the
tent his first time out. This was a failure of both tent site selection and of the bivy cover, as it offered no protection from the water
seeping into the tent. Since the poor judgement of my children isn’t
the topic of this article, we’ll focus on getting the bivy cover
back up to shape.
Gore-Tex from the factory has a
“durable water repellant” (DWR) applied to the fibers. If your
bivy cover easily accepts water rather than having water bead off,
then it’s likely you need to re-apply a coating or two. The three
main types of DWR are fluorocarbon-based, silicone-based, and
hydrocarbon-based polymers, and they come in both wash-in
and application varieties. There are a lot of “nano-tech” products on the
market now, many advertised as “silicone free” but from the reviews I’ve researched and the single
product I tested, they come with mixed results.
Wash-in is likely the easiest method, as it lets the washing mashing do all the work. This will generally
apply the DWR evenly, inside and out. For something like a bivy cover
this should be just fine, but for something like a Gore-Tex jacket with a
sewn-in liner, it may not be the best choice as it may change the
ability of the liner to wick moisture.
Application, either spritz on or spray
on, has the benefit of being a readily available option in most big
box stores and sporting goods stores. You’ll see these as various
offerings from Scotchguard and Sno-Seal in most chain stores, and
specialty stores may also carry NikWax.
However you treat your surplus bivy
cover, understand that it isn't waterproof any more, only water
repellant now, but just like older canvas bivouac covers it is still an incredible value-add if you have to camp without a tent. If you also have cotton bivy covers, then there are a lot of wax-based fabric
treatment options that can really help increase the water resistance,
some cheaper than others. (Erin wrote about waterproofing cotton with wax in this article.)
What I did to pep up my son's bivy cover was to spray the outside with Tex-10 water repellent, which turned out
to be really expensive and didn’t give the results I wanted. It was difficult to get an even spread/penetration with the spritzer, and so the next day some areas beaded water beautifully, while other areas soaked up water like a sponge. It's not a great value for the performance, so I can’t recommend it.
For a
second treatment I turned the bivy covers inside-out, liberally
sprayed them with an Atsko Silicone Water-Guard from Walmart, and let
them dry hanging outside overnight. The next morning I tossed them
into the dryer and tumbled them on low heat for 20 minutes, and the
results were much, much better. The organic solvent provided
much easier product distribution through the fabric than the water
solvent of the Tex-10, and while the environment might take a hit,
better performance for 25% of the price seems like a good thing for
us blue collar types.
If I have to do this again, I’ll
probably plan ahead and order a NikWax wash-in product, as they have
the most consistently positive reviews for treating hard use outdoor
gear. NikWax products are also beeswax-based, for those who might prefer that over silicone.
None of these treatments last forever,
so you will end up re-applying as needed to keep performance at an
acceptable level. In Alaska that’s probably going to be more often
than Arizona or North Carolina.
Stay dry!
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