Silnylon “Misting” and Ray Jardine

[Linsey Budden]

Both my silnylon (seconds) MYOG poncho tarps, my first silnylon (1sts) MYOG tarp/Wheelen lean-to and my GG Spinntwinn have misted through. My tarp made of Ray-Way silnylon has NEVER misted through so I firmly believe in Mr. Jardines claim that his proprietary silnylon coating eliminates misting. Also the Ray-Way silnylon has a slightly crinklier feel.

[Vick Hines]

Not all silnylon is created equal. Simple silicone impregnated fabric will seap under a small head of water (6 to 8 inches) and raindrops will sploot a light spray through it because they focus a very high head on a small area. This is in addition to their knocking condensate off the inside. Double coated silnylon which goes through the process twice – once on each side – is functionally waterproof and will not mist. Ditto for fabric that has a film of polyurethane over the silnylon. However, the latter has all the disadvantages of polyurethane and tends to delaminate.

[Don Selesky]

I intend to try to add more silicon on the underside of the tarp to gain a better seal against water penetration. It will add a few ounces, but still be much lighter than straight PU-coated tarps.

[David Olsen]

And some silnylon is a blend with a touch of urethane in the
mixture which can be applied to one of both sides and in lighter or heavier amounts.

There is no free lunch, although some are tastier than others.

[Don Selesky]

I'm assuming that the MLD SpectraLight [Cuben] is silicon coated only – no PU.

While there may no free lunch, sometimes you can season to taste. :-)

[Eric Blumensaadt]

Would GTX PacLite laminate be heavier than medium weight PU coating?

If so the expense may be worth it to avoid the misting problems in Silnylon fabrics.
But then it's likely not going to pass flame retardent tests.

Jim Woods 5:1 ratio of mineral spirits to silicon applied with a VERY low nap roller may just be the answer for those who love their tent but hate its misting.

Eric

[John G]

How can you tell if the silnylon is single or double coated ? Is the standard 1.1 (1.35 after coating) fabric sold by thru-hiker, or OWFINC double coated ?

Also, does anyone know where to get 20-40 denier ripstop with silicone coating on the outside, but a PU coating on the inside ?

[Don Selesky]

No idea whether it's single or double coated, only that it's .65 SpectraLight (Cuben), and I assume that there's no PU coating on it.

[Vick Hines]

JohnG.
The only way to tell about double coating is what the manufacturer claims. American Home and Habitat (americanhomeandhabitat.com) is one source. It sometimes (sporadically) shows up at other fabric sources.

None of this applies to Cuben which is a fiber-reinforced Mylar (polyester) film.

[David Olsen]

I say again, there is no free lunch. A lightweight coating,
say .3 oz, whether silicone or urethane is going to have similar
water resistance under pressure. If you increase the coating
to .5 oz or 1 oz or 1.5 oz or 2 oz you will get correspondingly more resistance under pressure as well as
more weight.

Paclite in its lightest versions is similar to a 1.9 oz
nylon with a .5 oz coatings or urethane or silicone.

The advantage to silicone is its durability in long term
damp conditions and that fact it increases the tear
strength of the fabric it is applied to.

Again I say that you could carry two silicone tarps for
the weight of 1 urethane tarp. Double them up and you
would have no misting issues at all. Or maybe carry
a bivy sack instead and get a ground sheet and bug and
wind protection too.

[Don Selesky]

"I say again, there is no free lunch."

Unfortunately, too true.

"Again I say that you could carry two silicone tarps for
the weight of 1 urethane tarp. Double them up and you
would have no misting issues at all. Or maybe carry
a bivy sack instead and get a ground sheet and bug and
wind protection too."

I would assume that adding extra silicone to one tarp is lighter, but functionally equivalent, to two normal silicone tarps.

I think what I've come to is, I'd rather carry a few extra ounces and not have misting spray over my face at night. As long as the ounces don't start adding up to pounds…

Damn, I *hate* trade-offs. :-)

[Scott Bentz]

This discussion has been interesting to me. I just got back from 2 weeks at Philmont Scout Ranch, New Mexico. 2 of us had Gossamer Gear "The One" tents with spinnaker cloth. It rained six days or nights. I had light condensation inside the tent on the wet days. Very little to none on the dry days. One night I distinctly remember feeling a misting in the tent. It had rained that day and the tent was wet. A light layer of condensation had formed on the inside of the tent. That was a first for me in that tent. The misting was also noticed by the other guy with The One. It was only noticed one night even though we had other nights with substantial rain with large puddles around the camp.

The misting was not enough to wet or saturate a bag. In fact. it was almost so little I thought I was imagining it. Is it real or is it Memorex? I don't know.

[Don Selesky]

"It was only noticed one night even though we had other nights with substantial rain with large puddles around the camp."

That was in a low humidity environment. It gets more interesting out East where the humidity often hovers in the 90s.

The misting sounds more like fabric penetration than condensation being consistently knocked off (not that they're mutually exclusive).

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