Some new Tent ideas I have up on Kickstarter

Great question Niek,

Probably UV resistance is the best place to start: it's very good. Better than nylon by a long shot. In fact if you used both side by side for a couple of weeks the polyester would be significantly stronger then the nylon. Not that most people should care (at least not much). I'll explain:

First I'm going to assume you mean sil/pu finished fabrics. The PU (polyurethane) on the underside makes the seams tapeable and that's the norm for US products. It's going to vary all over the map from source to source but the exact fabric I use in the MoonLights (20D 3xrip sil/pu) starts out about 15% lower strength than 20D ripstop sil/pu nylon from the same company (10% less in the warp direction, 20% less in the fill). But here's the thing: no one actually bases their tear strength requirements or even their desires on what is actually NEEDED. No one knows what that too-low number is. So we've gotten into a sort of tear strength arms race even though it's obvious that it's the tensile strength that a tent primarily needs (and all fabrics available are WAY overkill).

So I've taken it upon myself to ask repair departments of my clients (and Kelty, of course, when I was there) what, if any repairs they saw that were caused by the tear strength being too low. Tents age, UV damages fabric, surely there should be some indication of a lower limit to tear strength in use. But the answer was always no. No repairs ever because tear strength was too low. Actually is was quite striking. There were even tents sent in for repair that you could literally push your finger through which weren't being sent back to be fixed because of that; the customer hadn't damaged it and it was sent back for something else entirely!

As to abrasion resistance or puncture resistance, ALL the lightweight fabrics we use are just terrible – it takes the barest swoosh against a sharp rock or a gnarled tree to put a bunch of holes or a tear into a rainfly. About the only thing one can say about higher tear strength is that there's at least the theoretical possibility (and hope) that a tear won't propagate as much in a higher tear strength fabric. But prevent a tear? No way. This is when having some of the truly excellent repair tapes available can really save the day. I love modern repair tapes.

Side note: reinforcing stress points is absolutely necessary regardless of a fabric's tear strength or it will get ripped in use. Everyone seems to do at least a fair job of this so it's not really a differentiating feature.

Are you sorry you asked or have I answered your question?
Best,
Mike

Thanks Mike, for your extensive explanation! I will be ordering one.

All te best,
Niek

Thank you so much!
-Mike

Years ago I had some PU-coated gear, which, if not stored bone dry, and maybe even then, would develop almost impossible-to-remove odors from some degradation in the PU coating. Not sure if it was bacteria, mold, or just some reaction with water, but it made the gear (bivy sacks) unusable. How would your sil/PU fabrics behave in similar circumstances?

Great question Jim. It's all about the polyurethane (PU) coating and how it reacts to water over time (even very small amounts of water). What's happening is that the PU coating is slowly reacting with water – hydrolyzing – and loosing it's structure.

The quick, practical, and well known solution to the problem you mention is for the manufacturer to ask the fabric supplier to ask the finisher for a polyETHER based polyurethane rather than one based on polyESTER. This seems to be the solution.

There might also be another issue buried in there. I'm now talking about using the wrong PU – polyESTER based PU – and still wondering why a "dry" product's coatings would degrade. How much water causes this and where it come from is a good question. If your tent was made of nylon (most are) and it felt basically dry, it could still have 1-2% water in it and that could be what caused the problem. In my mind that's another mark against using nylon fabrics in tents. If you have a nylon tent this would be a good reason to really bake it dry in the sun before storing it. New imperative: sun-bake it and quickly put it into dry storage.

We ask for polyETHER based PU coatings, of course.
And we use polyester fabrics which absorb no water to speak of.

It's kind of amusing that, as a fabric, polyester handles water fantastically well but as a component of a polyurethane it causes water problems. Chemistry: soooo many details. No wonder I went for Physics.

Here's two great resources if you want to look into it further:
http://pslc.ws/mactest/urethane.htm
http://en.wikipedia.org/wiki/Polyurethane

I like the design, and I think the port hole windows add to the appearance. I think your biggest challenge is the fact there are just so many tents out there to choose from. Seems to be a giant glut that clouds the issues and overwhelms the average consumer.

To satisfy my own selfish self interest I think you have the skills and talent to build new versions of old tent designs. Personally I would be thrilled if you would create a new version of the old North Face Morning Glory tent (4-Man) but using the ultralight fabrics of today.

Also an ultralight version of the Sierra Designs Octodome which had the built in fly so even in the rainy Pacific Northwest, set up is not a problem. The same with the smaller Sierra Designs Aireflex Tent.

These were really cool tents but the problem is when they go up for sale on Craigslist or Ebay the price or the bidding war to obtain the artifact gives the buyer a hollow victory because half the time it stinks like cat urine because it is so old and you have to soak it in myrazyme for hours, and even after you handle that problem, the coatings are flaking off and there are the horrible stains and it is just depressing. Sort of like putting new wine into old bottles, not to get to biblical, but if they have people who create copies of classic cars it seems like a person could make a bundle making copies of classic tents. I like that new tent smell as opposed to the cat urine smell.