Copied and pasted from a post by Roger Caffin on another thread.

"Stock American silnylon is just too porous to be acceptable any more..."

I have seen this and statements like it posted on various threads here on BPL lately.

Is this really as bad as it sounds. Is there really no acceptable silnylon for us MYOG shelter types without resorting to imports?

Who actually has the good stuff?

Party On,

Newton

FWIW, Ray Jardine's kit page claims they treat their silnylon with some proprietary process to increase weatherproofing. I have no idea what that really means. I can say I made a tarp from his kit several years ago and it has served me well through heavy rain - no misting through.

http://www.rayjardine.com/ray-way/Tarp-Kit/index.htm

Edited by lettheguydance on 02/09/2011 07:45:21 MST.

How porous is too porous?

Silnylon available in Europe is rated at 2000mm hydrostatic head *after* abrasion.

How does that compare?

Most silnylon used here has a HH of about 1200mm. The issue is misting, which can and does happen in very high pressure rains (even the Tarptent.com website acknowledges this).

Lightheart tents makes its non-custom tents in China, where they have confirmed using silnylon with a HH of closer to 3500. Of course, it is heavier after this impregnation. Maybe 1.4 oz per sq yd?

To nearly triple the resistance to water under pressure, you would need to increase the
coating weight by a lot more than .05 ounces per square yard.

Just going by the marketing garble that comes from most manufacturers. From the Lightheart Gear site:


"What materials are LightHeart Tents made from? The body of the LightHeart Tent is made of 1.1 oz. sil-nylon (silicone impregnated ripstop nylon). The floors are made of 1.1 oz. sil-nylon (silicone impregnated ripstop nylon)."

"Is Sil-Nylon waterproof? Yes, sil-nylon is extremely waterproof within normal conditions. The standard gray tents come with sil-nylon that has a hydrostatic head specification of a minimum of 3500mm water. This is about 3 times the waterproof rating of standard sil-nylon."

So either someone has their head up their azz or they have access to something that others don't.

MLD and ThruHiker collaborate on silnylon and do independent testing to verify quality.

I recall about two years ago when they found all silnylon was failing due to some manufacturing process problem.

So, unless someone can provide first hand, independent, test results, I believe you are at the mercy of the marketing spiel.

Faith baby, you gotta have faith, cause science is way behind.

Marc and Judy have all of the requisite documentation on said fabric, I was talking with Judy about it just the other day. It has been suter tested and certified to the numbers they claim on the site.

The fabric in the gray standard model tents does come from Asia, it's sourced there, since the tents are manufactured there. They're working on trying to import some of said fabric.



I'm not sure what the difference is, but it's related to more than just "how much coating" is on the fabric.

I have the lab analysis certifications for both the gray and black sil-nylon tested in multiple locations from selvage to selvage that was used in our standard gray body/black floor tents (both Solo and Duo). I even have pictures of the Suter Test device in action on our materials showing the 3500 mm H2O reading on the pressure gauge as taken by our contracted witness. It also shows the sil-nylon material in the holder and there are no droplets showing. In fact, the material tested to over 4000 mm H2O but was blown off the sample holder device by the high pressure just above 4000 even though it had shown no leakage at that point.
The weights of our manufactured tents is extremely close to the weights of our custom made tents using US made sil-nylon (there are some slight manufacturing differences between the tents Judy makes and the manufactured versions) so my best estimate is that the materials are essentially the same weight (at least within our scale's accuracy and repeatability).
How do they do it? I am not sure but it is obviously not just thickness of the coating. I know it is not a pure silicone coating but I don't know the actual composition. We had a lot of discussions about whether to go with this upgraded material as we had the choice to use a lower hydrostatic head sil-nylon at a lower cost. In the end we decided to pay the extra money for the 3500 mm H20 material just to deflect the misting concerns. We think it is worth it.
Marc Penansky
LightHeart Gear

IMHO, given these validated tests, I am looking toward the Lightheart for my next shelter purchase. I am tired of the misting issues I have had with previous apparent waterproof shelters.

Thanks for posting Mark.

This is what I can tell you about the Asian silnylon. They use a type 6 yarn. This is not nearly as good as the high tenacity type 6.6 used by most Domestic mills. This lower quality Nylon has more stretch and less strength. Asian mills follow no Mil-Spec or ASTM standards so the material varies from roll to roll with some rolls having weaving flaws, frayed fabric, and coating inconsistencies throughout. Are some mills the exception? I am sure but overall their materials are of inferior quality..

Edited by Mountainfitter on 02/09/2011 18:18:04 MST.

I just buy (shelters) from MLD and call it good.

Lawson writes " This is what I can tell you about the Asian silnylon. They use a type 6 yarn. This is not nearly as good as the high tenacity type 6.6 used by most Domestic mills. This lower quality Nylon has more stretch and less strength. Asian mills follow no Mil-Spec or ASTM standards so the material varies from roll to roll with some rolls having weaving flaws, frayed fabric, and coating inconsistencies throughout. All the Asian silnylon I have seen is junk."

Operative phrase in that statement being "All the Asian silnylon I have seen". I may be mistaken, but I seriously doubt that Mr. Kline has actually been to Asia. So to make a blanket statement like this is frankly pretty silly. Yes, you can buy pretty crappy stuff in Asia and you can buy some really good Nylon 6.6 there also.

Yes, you can get fabric that meets ASTM standards and probably Mil-Spec. But that one I'm not sure. The reason the military buys US made goods is because it's the law (Berry Law to be exact). Not because you couldn't buy the same quality on the foreign market.

As to Rogers comment about "American silnylon not acceptable", that too is a matter of opinion. In this case his. We've sold thousands of tents that are used in harsh environments around the globe. It's been a long time since anyone's contacted us about having a misting issue. Currently all of our silnylon is US Domestic source.
It's a little easy to get carried away about all of this.

One should also note that until about 50 years ago, all tents made misted. It wasn't until tents started to be made from coated nylon that misting became a thing of the past. Tents made from either canvas or silk, didn't have coatings. They relied on the swelling of the yarn when wet to keep out the rain. Still under heavy rain storms, one could still experience misting. I know because I slept in canvas tents until I was 20.

Edited by rmoak on 02/09/2011 13:04:48 MST.

The official ones look expensive, but it seems like you could make one with a piece of pvc standpipe somewhat like this:
SPOT testing at equipped.com


3000 mmH2O is ~10 feetH2O so not too tall. The only trick is to seal the end with your test piece of silnylon so you can see the water drops press through, maybe a threaded fitting with a plug with the center cut out?

Edited by erdferkel on 02/09/2011 13:10:02 MST.

Misting is a big concern of mine as well. I use a 8 year old Equinox silnylon tarp, 5 year old BD Megalite, and my brother has a 2 year old Equinox tarp. None of them have ever misted. I can't say the same about my TT Rainbow or SMD Refuge.

On my last trip I abandoned my refuge for the second night of rain because of intense misting that wetted everything in the tent. To be fair I could have potentially reduced the intensity of the misting, wiping condensation from the inside roof and leaving the screen door open. The misting in the Rainbow wasn't as intense but neither was the rain.

I'll chime in that I've long been disappointed by silnylon's waterproofness....

"(Berry Law to be exact)"

The Berry Amendment, to be more exact. And it's a slightly misunderstood amendment as it stands now. It only requires DoD to "give PREFERENCE in procurement to domestically produced, manufactured, or home grown products, most notably food, clothing, fabrics, and specialty metals" [Wikipedia entry]. It doesn't require all purchases be domestic. FWIW.

Ron,

If Asian silnylon is so good why don't you use it?

Edited by Mountainfitter on 02/09/2011 18:19:06 MST.

Greg, that problem 2 years ago was with spinnaker fabric, not silnylon. Not only MLD and Thru-hiker but also Gossamer Gear ran into issues. I had to wait over a year for my now-beloved Squall Classic! Fortunately the new spinnaker--when they finally got it--tested out better than the old. However, I recently saw on Thru-hiker that the problem of spinnaker quality has arisen again.

I haven't had any misting issues with silnylon, even in heavy rains. I weathered a number of Colorado cloudbursts (several every evening for a week, about 30 min. of torrential rain and hail with each) with a SMD Lunar Solo with zero problems. Lots of condensation, yes, which the hail in particular tended to knock off the tent wall (as did my dog's tail wagging!), but nothing coming through the fabric except for one tiny spot on the horizontal seam that I missed in my initial seam sealing. I have two larger silnylon tents (Tarptent Squall 2 and Rainshadow) that have been in extended heavy rain with no misting. I also have silnylon rain gear which has had zero leakage since I seam-sealed it. Maybe I've just been lucky, but I personally have never experienced a misting problem.

Like Ron, I grew up in the days when you didn't dare touch the inside of a tent when it was raining! Maybe that makes my perspective a bit different.

Edited by hikinggranny on 02/09/2011 14:10:10 MST.

"Misting is a big concern of mine as well. I use a 8 year old Equinox silnylon tarp, 5 year old BD Megalite, and my brother has a 2 year old Equinox tarp. None of them have ever misted. I can't say the same about my TT Rainbow or SMD Refuge.

On my last trip I abandoned my refuge for the second night of rain because of intense misting that wetted everything in the tent. To be fair I could have potentially reduced the intensity of the misting, wiping condensation from the inside roof and leaving the screen door open. The misting in the Rainbow wasn't as intense but neither was the rain."

Do you think the angle of the shelter's pitch would change anything in you experiences?
Do you set up your older tarps using the same angle of pitch as the rainbow or refuge?

A steep pitch would lessen the force of rainfall.

In my experience in using surplus parachute silks for survival shelters, steep sided teepees can be made of UNCOATED 1.1 oz nylon that do a pretty
good job of keeping out weather, and two layers of it will do as well as any coated fabric. (I would in fact use a 2 layer dwr pyramid if I did a lot of cold weather trips
over a 1 layer coated mid.)

Take that same fabric and make a very shallow lean-to and rain will penetrate.