Silpoly for shelters

[coloradoan]

I have seen that a few manufacturers have switched some production over from silnylon to silpoly (Six Moon Designs, Black Diamond). It sounds like the main tradeoff is reduced strength with the silpoly but also reduced stretching/sagging. Silpoly isn't exactly new, so it's not like shelter makers haven't heard of it - I guess they've decided that the reduced strength isn't worth the reduction in sagging.

I know there are people on here who have tried a lot of shelters and even messed with fabrics. What are your thoughts on silpoly? Is there a significant difference in performance? Is the difference between silnylon vs silpoly important enough to be a deciding factor in shelter selection?

I've been in the market for a new flat tarp and possibly a mid tent, so all of the sudden I've been reading up and nearly convincing myself that I need a silpoly shelter - but I don't want to fall for a fad.

 

[Coat4gun]

A lot of folks over at hammockforums.net use these line tarp tensioners

to help with silnylon sagging with hammock tarps. Could work with silnylon tents as well. Would need a few inches of free cordage to use but worth a try.
As far as longevity of silnylon vs silpoly. I don't have enough long term experience to know. I do know I don't like polyurethane coated fabrics because of how it deteriorates over time and gets gummy. I have had to trash several tents because of that.

 

[Voyageur]

Here is some reading on the subject:

Durston Gear | Materials

A more technical look at the fabrics and coatings used to build Durston tents including why we choose the materials that we do.

durstongear.com

 

[Coat4gun]

^^^^^^^^^^ Good info in this article - well worth the time to read ^^^^^^^^^^^^^

 

[Singapore_swing]

I can only give you a personal anecdote:
I made my own hexagonal silpoly tarp last summer for my hammock system. A few weeks later we have to deal with hurricane Ida. I figured what the heck. I set up my tarp & hammock and throw in some weighted bags.
2 days later I go for a look. Bone dry in and under the hammock. The tarp was still taught and in tact. No holes, no tears. Lots of wind and small branches flying all over. No issues!
And it’s so unbelievably light weight.
I’m located in the mid-Atlantic (obviously).

 

[Cdpp880]

I have a pyramid shelter made out of it. It’s super light weight but can be a pain to get pitched right on uneven ground. On level ground it’s easy but unleveled ground it can be a pain.

 

[Mike Islander]

Very little strength penalty when new. Exposing nylon to sun dramatically weakens it. After the first season, the poly will likely be stronger.

Poly is hydrophobic. Nylon takes on water. Nylon sags. Poly doesn't. I have a Durston 2P. Awesome tent.

After a week under withering summer storms, bone dry inside and as taught a when I set it.

 

[Dos Perros]

I think you need to know your application. If it's a good weather hunt, light winds, or you're sure you'll be able to get out of the wind, silpoly is a shrewd weight savings and cost savings decision. If you're going to be more remote and your life will depend on it, I would not trust silpoly, having seen a shelter destroyed in the wind.

 

[Mike Islander]

I think you need to know your application. If it's a good weather hunt, light winds, or you're sure you'll be able to get out of the wind, silpoly is a shrewd weight savings and cost savings decision. If you're going to be more remote and your life will depend on it, I would not trust silpoly, having seen a shelter destroyed in the wind.

Definitely depends on the actual fabric. Many versions of SP. It's got 95% of the strength of new, dry nylon. Get nylon wet, SP is stronger. Use nylon in the sun, SP can be 40% stronger after a season. If something tore up a silpoly shelter in the wind, nylon wouldn't save the day. Canvas for sure.

 

[Dos Perros]

Definitely depends on the actual fabric. Many versions of SP. It's got 95% of the strength of new, dry nylon. Get nylon wet, SP is stronger. Use nylon in the sun, SP can be 40% stronger after a season. If something tore up a silpoly shelter in the wind, nylon wouldn't save the day. Canvas for sure.

Had a silnylon shelter from a reputable manufacturer right next to it and it held up fine. Maybe the silpoly one had a flaw? Possible.

I see silpoly as a cost informed decision, not a performance informed decision.

 

[Mike Islander]

Had a silnylon shelter from a reputable manufacturer right next to it and it held up fine. Maybe the silpoly one had a flaw? Possible.

I see silpoly as a cost informed decision, not a performance informed decision.

I don't know enough to even guess why one tore and the other didn't. I'm sure there are techniques in construction that could make a huge difference. I do know that the Durston tents, which are silpoly, have seen tons of through-hike miles and have handled conditions very well. His silpoly tents sell out in minutes with each run.

I see silpoly as a performance preference over silnylon. I love that it doesn't sag. I love that it doesn't hold water. I love that it retains its strength when exposed to UV. But whether there are silnylon materials built in such a way that makes them better, I really don't know. My experience is limited to the 10 or so tents that I own, and only one is silpoly so far.

 

[Dos Perros]

If reputable manufacturers can save cost AND add performance, then they certainly will and silnylon will be obsolete.

 

[Mike Islander]

I don't think they save any money using poly.

 

[Brad@Argali]

I have seen that a few manufacturers have switched some production over from silnylon to silpoly (Six Moon Designs, Black Diamond). It sounds like the main tradeoff is reduced strength with the silpoly but also reduced stretching/sagging. Silpoly isn't exactly new, so it's not like shelter makers haven't heard of it - I guess they've decided that the reduced strength isn't worth the reduction in sagging.

I know there are people on here who have tried a lot of shelters and even messed with fabrics. What are your thoughts on silpoly? Is there a significant difference in performance? Is the difference between silnylon vs silpoly important enough to be a deciding factor in shelter selection?

I've been in the market for a new flat tarp and possibly a mid tent, so all of the sudden I've been reading up and nearly convincing myself that I need a silpoly shelter - but I don't want to fall for a fad.

There is definitely a reason some of us are using silpoly in shelters, and it isn't based on cost savings (there isn't any). I just wrote and published an article on this subject that goes deep on the topic if you want to geek out. As others have noted, silpoly is not weaker, and the data bear that out.

Tent Fabric for Backpack and Lightweight Tents | argalioutdoors.com

An in depth look into the world of tent fabrics.

argalioutdoors.com

 

[Voyageur]

@Brad@Argali
Thanks for posting the tent fabric article. Interesting reading.

 

[Dos Perros]

Just perusing Ripstop by the Roll:

1.1 oz Silpoly $6.75/yard
1.1 oz Silnylon $12.50/yard

Perhaps the silpoly is more expensive to manufacture?

I had only guessed the costs must be lower because for like shelters, for example comparing the old JimmyTarps Hudson (silpoly) to a Seek Outside Cimarron (silnylon), Seek was charging quite a bit more.

I personally won't be convinced silpoly is superior until reputable manufacturers start to use it, having owned shelters in both materials myself.

 

[as.ks.ak]

Quit messing with the sil-anything and spend half a mortgage payment on some dyneema and make the shelter of your dreams and just be done with it.


Sent from my iPhone using Tapatalk

 

[Kevin_t]

We made testers several years ago of the best SilPoly we could find . They were tested from Colorado to Kodiak in Redcliff size shelters , plus an eolus prototype , and an 8 person . Everyone proffered the Nylon version . There is a substantial cost savings with SilPoly compared to the best Nylons . Compare them based on rip and tear strength , especially once there is a hole and the difference is substantial . Strength wise , iis similar to Sil PU blends in a 30d , which we do not offer on larger shelters anymore , in fact not even on the smaller just floors .

In smaller shelters it is fine , but has no real benefit . SilPoly still has a fair amount of bias give and stretch . In my opinion medium Mid size shelters and smaller , you can save some money , and a little weight as long as you can walk out if something goes sideways .

As for UV , color has a tremendous impact . In 12 years of making neutral colored shelters never have I seen a shelter suffer from what I would term UV degradation . I have seen some bright colored shelters we built and tested suffer .

As for stretch , it is way overstated . Every shelter will stretch with a snow load . All other stretch is generally easy to compensate with a pole click or little tension

There are some other downsides we found in testing , but I’m not going to articulate them and will let the manufacturers find out if they have those downsides .

 

[dandurston]

I'm a bit late to this thread, but here's a few quick comments:

"If reputable manufacturers can save cost AND add performance, then they certainly will and silnylon will be obsolete."
Silpoly doesn't save cost, but it does add performance. Tons of companies are switching like Black Diamond, Nemo, MEC, SMD etc. Even ones that were originally against it like Tarptent are now switching.

"I personally won't be convinced silpoly is superior until reputable manufacturers start to use it, having owned shelters in both materials myself."
I'm not sure what it would take to convince you, but tons of reputable companies are switching, with Black Diamond and Tarptent being two of the biggest names recently.

 

[dandurston]

In smaller shelters it is fine , but has no real benefit .

This is really inaccurate. Yes both poly and nylon stretch, but stretch is not the problem -it's sag. The two big problems with silnylon are sag and water absorption. Silpoly is drastically better at these things to give a huge real world benefit.

The core issue is that nylon has amide bonds in the chemistry that make it hydrophilic (love water) whereas poly is hydrophobic (hates water). Nylon's love for absorbing water leads to several issues.

1) Sag / Expansion
As nylon absorbs water it unavoidably expands by 2-4% whereas poly expands drastically less at 0.2 - 0.4%. The arch of a smaller tent is about 150", which means you'd have 3-6" of sag in a silnylon tent once it is saturated. That's a lot of slack, whereas poly would have at most 1/2" sag. This means a nylon shelter becomes limp and structurally unsound (particularly for trekking pole tents where the fabric is part of the structure) whereas poly holds much tighter. Go past any campground after a good rain and you'll see a sea of limp nylon tents. No one argues this isn't a major real world benefit to poly. There are some good pictures of this here:

Polyester versus Nylon | TheTentLab​

thetentlab.com

2) Water Absorption
Since nylon is hydrophilic (loves water) so it soaks up a ton of water which makes it heavy and slow to dry. The coatings affect how fast it soaks up water, but in prolonged wet conditions nylon can easily gain 100% of it's weight in water. That's absorbed INSIDE the fabric and not something you can shake off, where as poly is hydrophobic (hates water) so it absorbs virtually none. Either type will have water on the surface, but nylon has drastically more inside which makes it heavy, slow to dry, and more prone to degradation as it's harder to get 100% dry. Even when nylon feels dry it can be harbouring moisture inside the fibers that lead to degradation when it's packed light that.