Sil-nylon Misting

[Sam Farrington]

Since my earlier post on this threat, still find that silnylon (silicon coated 1.1 oz nylon) from Quest(1st quality) and Warmlite (bought in person at the mfg.)is better quality than others, but have not tried the product from Thru-hiker, said on this site to be high quality by Ron Bell, due to the limited color choice.
Have also noted the more recent posts with first-hand accounts attesting to the value of over-coating with the Atsko silicon spray, so this year will lightly treat my TT and MYOG silnylon tents with Atsko.
There is plenty of inexpensive silnylon available, but have not found any cheap stuff that is of high quality. Since the high quality sells for less than half the price of Cuben, or around $10 a running yard (1.66 sy), that is well within a reasonable price frame for me to have a much greater assurance of a dry tent.
Also use a small ball point needle, cotton covered polyester thread, flat felled seams, reinforced stress points, and triple coat seams with very diluted silicone to assure against seam leakage. The last craftsman to remind me that many thin coats are much more durable than a few thick ones was not a tent, but a bootmaker. 1.1 oz silnylon is so thin that there is a greater likelihood of pores opening up at needle holes, so a little extra time in sealing is well worth it.
I agree that it is worth a few extra dollars a yard to obtain quality materials before spending many hours making a tent.
Also agree that whatever the material, every tent has a limited life span, and good care, storage and maintenance will extend it quite a bit. Do not leave my tents up during the day, and fold and roll them before packing. When I used tents urethane coated on one side only, also used a mesh bag and carried the tent outside the pack so that it could dry a bit while while hiking. (There is a good photo in the single wall tent reviews on this site of a water logged urethane coated Montbell Crescent). Since switching to silnylon, have not found this necessary, as the double coat greatly reduces water absorption.
Also hope that eventually, some of the silicon/urethane coated materials that the large mfgs. use will become available for MYOG folks and small tentmakers. When BD began making tents of Epic Malibu, that material (probably seconds)became available to us, and now that BD has switched to a better, but still light material, who knows?
The best silnylon I've found is the material on a bug tent fly from Wilderness Equipment (.com.au). It has a matte finish and is a little heavier than 1.4 oz., but has weathered many storms and much use without any sign of failure.

[David Olsen]

"When BD began making tents of Epic Malibu, that material (probably seconds)became available to us, and now that BD has switched to a better, but still light material, who knows?"

They quit selling Epic to cottage manufacturers in reasonable
quantities, except for 2nds after BD started using it for tents.

eVent did the same.

[George Matthews]

Last fall I watched misting in action. Was in Contrail. A very heavy downpour woke me up. I turned on my head light and was looking upwards. It seemed to be coming from the top/peak front.

Not sure if the source was all just from that upper seam where the pole pushes the tarptent up. Could maybe been from the vent too. Some rain splashing off the vestibule in front up into the vent. I'm not sure.

I assumed it was the nature of the material because I read about misting on the tarptent website in FAQ. Watching it for a while, I felt it was not bad. I turned off my light and went back to sleep.

My quilt was slightly wet around the bottom and side edges. I did not have the side and back down.

After experiencing such a awesome downpour, I believe the Contrail held up well. ymmv of course.

[Eric Blumensaadt]

I solved the potential problem by coating the top 1/2 of my TT Moment with a 5:1 (by volume) ratio of ODORLESS mineral spirits to GE Silicon II caulk. I put it in a very clean plastic peanut butter jar so I could shake it vigorously to easily and more thoroughly mis it and keep it mixed.

Then, starting at the top, I painted it on with a 1 1/2" wide paintbrush that was only partially saturated with the solution, to avoid runs down the side of the tent.

[Brett Rasmussen]

I also coated the TT Moment with a 5:1 ratio. It was a fairly heavy coating than might have been done and covered the entire upper portion of the tent. It now weight 31.1 oz on my scale. I for got to weigh it prior to treatment, but according to listed spec.s that would be a weight gain of 4.6 oz. I would say that is the very most weight gain you could expect for the treatment of a tent of that size. I've also treated several Black Diamond tents made of epic fabric with similar weight gain results.

[jim jessop]

I notice that some believe examples of misting to be the result of condensation knocked off the inside of the sil-nylon.

Does anyone know or have experience of whether this can or can't happen with cuben fibre?

[Ross P Hemphill]

As far as I'm concerned, misting is not the same as condensation being knocked off. A number of people with lots of experience have observed the difference. When you wipe the water off the fabric, and you have new water appearing, following behind your wiping… condensation would not be forming at the rates and in the patterns that have been seen… Not to mention that silnylon's "hydrostatic head" (what pressure water must be at to push through) is typically very low in comparison to other materials considered "waterproof," besides being less than the pressure that it is said (hard) rain drops can reach. Etc.

Condensation being knocked off can be an annoying problem, certainly, but I'm more concerned about ending up cold and wet from "misting" than from that. I've dealt with condensation plenty, but storm water coming straight through your shelter's walls/roof is way less fun.

To try to answer your question(s): yes, condensation can form on, and get knocked off of cuben just fine; no, misting's not likely to happen with cuben, due to construction differences.

[Thomas Burns]

For what's worth:

I've only experienced misting and/ or getting "rained on" during heavy rains. Setting up close to water on high-humidity days has produced condensation on the inside of the tent but not the other problems.

I experienced getting rained on in a brand-new Moment (once) and also in my The One (once). In both cases, I also had pretty heavy condensation on the inside of the tent. My impression (I have no real proof or definitive scientific study — sorry) was that the rain was knocking the condensation on the inner walls. Thus, I preliminarily conclude that the same problem will occur with "waterproof" materials, but again I draw that conclusion based on the assumption that the rain is knocking off internal condensation, and I could be wrong about that.

Since my first bout with the problem, I've been using a Heetsheets emergency bivy (3.5 oz) over top of my sleeping bag to protect it from getting wet during rainy nights. If you hunker down in the Heetsheets, you can even prevent the tiny droplets of water from hitting your face.

Also, the usual advice applies. Set up in well-ventilated locations away from water. Pitch the tent so as to allow max ventilation. Shelters with good vestibules (and good covers for them) will allow ventilation without rain blowing into your shelter.

Sadly, I can't afford to buy yet another shelter right now. (Besides, the ZPack shelter of my dreams isn't even taking orders, they are so backed up. If someone would like to send me a nice cuben shelter or some other shelter that purports to be waterproof, I would be glad to try it out in the rain.If it works, don't expect to get it back, though. ;-D

Generally speaking, these problems have occurred only rarely. It would be a shame to "throw the baby out with the bath water," as the old saying goes.

Cordially,

Stargazer

[Matthew Swierkowski]

I got a PM asking for more info on the treatments I have mentioned here and in other threads (the "painting" method and the Aksto spray). Since I ended up typing up a lenghty detailed reply, I thought I would paste it in here in case anyone else was curious. Here it is:

"As for the sil treatments, I have posted my experiences in a few threads on BPL, but I'll try to sum things up here for you since that stuff got a little spread around. I have tried the Aksto spray on my poncho, and painted on the diluted silicone on the poncho and on my Squall.

First off the Aksto spray. The poncho I have is an Equinox Terrapin I bought from Campmor. I suspect the quality of the fabric was average to below average as it started leaking not to long after I bought it. I then noticed on a trip last year that it was not just misting, water was literally going right through it. I have to admit that I did do something really stupid with the poncho. I washed it in the washing machine. This was well after it had started leaking though. At any rate, I think I washed a good bit of the silicone out of the material. So, with all that up front info, I then bought 2 cans of the Aksto spray from Wal-Mart, set it up in my garage and went to town on it. After a couple of coatings (both inside and out) I took it out for testing. It appeared to basically be waterproof except that I got a little leakage through the hood where it was pressed up against my head. So I am thinking that on a higher quality sil item the spray is probably sufficient. Plus it's really easy to apply. If you go this route I would just recommend setting up your tent, and then you can just spray it on. You might want to do both sides.

As for the "painting" method. I first found out about this from Jim Woods site. My Squall misted on me in some really heavy rain on one trip, and even though it wasn't a big deal I just didn't like it. So I decided to try the painting method. I experimented with a 4:1 ratio. It's a real pain in the rear because you have to pour some mineral spirits (definitely get odorless or low odor…the normal stuff works too but the treated item will smell like mineral spirits for a while) in a container, put some silicone in there (I used the GE II from Lowes in all cases), and then mix for a while to get the silicone to break down. Once mixed the process is simple. Just use a paint brush and work it into the fabric wherever you want to treat it. I set the Squall up in the yard, and did the underside of the canopy. After that dried I laid it out in my garage inside out, and did the floor with the same ratio. One tip here is to not move the item until it dries. I moved it too soon, and now my Squall floor has a bunch of streaks on it. Functionally it works fine, but it looks pretty funky. Anyway, I did basically the same thing with the poncho where I laid it out on the garage floor, and used weights to pull it taught. Oh yeah, one other tip here is if you are going to lay the item out on the ground put something down to set it on because the diluted silicone may soak through, and then you’ll get a bunch of dirt and crap stuck to the other side.

At any rate, the paint on method seems to put a thicker coating of silicone on. You will also notice that once it cures it leaves the item slightly tacky (i.e. sticky feeling). After a little testing I can also confirm that the paint on method has returned both items to being waterproof.

I hope I answered your questions. If you have any more questions about this let my know…no sense re-inventing the wheel.

Oh yeah, and I almost forgot the most important thing. The weight increase is basically gonna be the amount of silicone you use. So for example, if you mix up a 5 oz 4:1 ratio batch (i.e. 4 oz of mineral spirits and 1 oz of silicone), and use it all up covering all the areas you want treated, it's going to add around an ounce to the weight of the item. Just for comparison, I think I used somewhere between 1 – 2 oz of silicone on the Squall (covered the canopy and floor), and had a little left over."

[JM Addleman]

It seems like recoating your silnylon is just another simple piece of gear maintenance, like reapplying DWR or storing your sleeping bag lofted. Good to know!

I'm interested to see if anyone at all has any anecdotal evidence of Jardine's fabric misting. I have seen a couple of people say that it has not misted in their experience, and it would be nice if his 'proprietary treatment' actually worked (plus the fabric is $2.50 a foot!).

[Franco Darioli]

"It's a real pain in the rear because you have to pour some mineral spirits (definitely get odorless or low odor…the normal stuff works too but the treated item will smell like mineral spirits for a while) in a container, put some silicone in there (I used the GE II from Lowes in all cases), and then mix for a while to get the silicone to break down."

Yes doing it that way it is a pain but also the wrong way…

Put a quantity of silicone in a container . Pour 4-5 times (whatever dilution you are aiming for) of mineral spirit into another.
Now add a few drops of mineral spirit to the silicone and mix. Keep adding and mixing till it is all diluted. Much faster this way. Again it is the same principle as adding milk to flour when you make white sauce. Ask your wife why, if you can't cook.
Franco

[Matthew Swierkowski]

"Yes doing it that way it is a pain but also the wrong way…"

Oh come on Franco, there's really no wrong way to do it…just easier ways :-)

Seriously though, your method of adding the mineral spirits slowly sounds like a good idea. I was just following the directions that Jim Woods gave on his site. Putting the silicone and mineral spirits together all at once works too, it just takes about 5 minutes of brisk stirring. I also noticed someone posted earlier in the thread that they used a peanut butter jar to combine the silicone and mineral spirits, and just shook it till it was mixed. Perhaps that's an even better method?

[Jon Sabo]

"However, this second tarp seems to be much more "silicony" than the first one was at the same age. Admittedly, the first one got HAMMERED many times in huge rainstorms on a London-Istanbul bike tour"

I tried to PM you about this but it doesn't look like you have it set up; do you have a ride report posted somewhere about this trip? That sounds like an awesome bike trip.

[Roger Caffin]

Hi Arr

> When you wipe the water off the fabric, and you have new water appearing, following
> behind your wiping… condensation would not be forming at the rates and in the
> patterns that have been seen..
Sorry, but I would to really disagree with you here.
Part of the problem is that wiping does not remove all the water: some always gets left behind. And when you are wiping the roof your breath is often quite close to this very cold roof …

We had one night last week in the mountains when the air was very still and the night sky was very clear, and both the inside **and the outside** of my tent were soaking wet. Wiping reduced the surface loading, but it had no chance of eliminating it. When a breeze struck up a few hours later the tent quickly dried off.

Cheers

[Steven McAllister]

The misting that I have experienced with silnylon has always been condensation. But I am only a weekender, but have been on 10 day trips where it rained every day.

The only time I've had more than a light coating of water inside my shelter was in very extreme wet conditions, like inside the rain cloud itself and I do backpack in the very wet North East US.

I always use single wall shelters either tarp or tarptent.

I have seen how some people have complained about condensation and it has been poor ventilation in almost all cases.

My opinion, if you can except that getting a little wet is part of the outdoor experience and don't let it bother you, you will be much happier and will sleep better. There is nothing wrong with a little spray, mist or condensation in most cases.

Silnylon is nowhere near as bad as the canvas shelters that I grew up with. We just excepted that water would seep through the material and didn't let it bother us.

[Jerry Adams]

I've experienced misting but it's so minor I've not bothered doing anything about it.

Besides, you will get condensation, which will get knocked off a little.

You need DWR coating on your sleeping bag.

Overnight, body heat will evaporate some water from your sleeping bag.

I think synthetic bag is better, but I don't have much experience with down.

I always get 2nds silnylon from http://www.owfinc.com/. I see Quest also has 2nds. It's about $6 per yard. Never had a problem with defects.

But then I get misting and maybe that's because I'm so cheap and buy 2nds :)

[John Drollette]

Sorry, I thought I was set up for PM. ??? I send and receive them just fine. You could always try again, or feel free to email me at my trail name (seen at left) at hotmail.

No writeup on the bike trip. It was in 2000, before I was on the web much. Yes, it was awesome – my first bike tour of more than 1 night. Shoot me an email per above if you have any questions.

@ Matthew: Thanks very much for the detailed PM on recoating. I have been slammed lately with PCT prep but have been meaning to thank you for the info. I'd read different reports about Astko (not sticking to sil) but now have confidence to try it.

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