Tarp/Tent materials… Is poly just too heavy?

The durability of the fabric is not imagined. 75D fabric (on the Poly U coated material) is generally going to be more durable to punctures and abrasion than 30D fabric, and likely more than the cuben (depending on the cuben weight).

Some more comments: 1500mm and 3000mm are the measured values (in HH–hydrostatic head) for the water permeability of the fabric. 1500 for the fly, and 3000 for the tent floor presumably.

I'd also bet the tent is made out of Polyurethane coated nylon, not polyester, but I might be off on that. PU coating is more waterproof, but heavier. EDIT: It very well could be polyester, but it's the weight of the fabric, combined with the WP coating that makes it heavier, not the polyester vs. nylon.

You can buy PU coated tarps. <$20 at your local Walmart.

It's not a nylon vs polyester thing. Spinniker tarps and shelters (I don't think there are any on the market anymore) are made out of a silicon coated polyester much like Silnylon is silicon coated nylon. It wasn't as waterproof in many cases (it seemed to have good and bad batches) or as strong as silnylon but it was lighter and didn't have as much stretch.

six moon designs makes the same shelter (the skyscape) in cuben, sil, and a more traditional PU fabric if you want to see the weight difference.

I doubt any cottage manufacturer (at least known to me and popular on BPL) would bother making anything with something heavier than silnylon. Sil is extremely tough and will survive many, many years of active service and multiple thru hikes if properly cared for.

However you are right, the durability on sil and cuben is not desirable for a family car camping tent. Their stretch resistance is high, but their tear and puncture resistance is less than stellar. You don't have to baby either product, but it should be reserved for use by people who will respect the material and not just toss it around like a mil-spec bag.

For any application with children who aren't yet trustworthy around delicate materials, a traditional heavy-as-%#@! tent will have to do.

I believe Oware has the option of getting their pyramid shelters in 70D nylon, instead of the usual 30D silnylon:

http://shop.bivysack.com/Pyramid-Tarp-9×9-1Pyramid9x9.htm

Thanks for all of the great replies.

I'd like to take my daughter out tarp camping this year… she just turned 5 and would be up to a small backpacking trip where we walk 2-4 miles a day. She's pretty respectful of gear but she's also a young kid and likes to play. Durability is more important than weight for this kind of trip (for me) so that's why I was looking into the materials that our family tent is made out of. You've all been quite helpful.

Cheers

Polyester has the market cornered on car camping tents because its cheap, doesn't sag like nylon when wet, and has much better resistance to UV. Finding it in that weight would be a challenge though. I would probably go with 70d nylon and call it a day. Plenty cheap and plenty durable.

Ryan

The old Golite shelters were made from a heavier 1.7oz silnylon (most is 1.1oz) and are very burly. In 2012?? They changed to a PU coated nylon that wasn't as strong.

I've seen 40d silnylon here and there. I wonder if that was what Golite was using.

Ryan

Appy Trails make lightweight shelters out of coated polyester. http://appytrails.com/index.html

30d polyester and 30d nylon with the same amount of picks per inch would weight the exact same. So its not really a weight issue. The problem is finding the raw fiber. Nylon in low denier is cheaper and more available.

A silicone coated polyester would be stronger, have less stretch, have better uv, and wouldn't absorb moisture. So in my opinion it would be a much better fabric for tents and tarps than a silnylon.

Ripstop by the roll has a 20×50 that looks super interesting. I hope Kyle brings out a 30×30 in the future.

Nylon is stronger for the respective weight as compared to polyester. It's a lighter material.

Specific gravity of nylon is 1.14 and polyester is 1.38 (the larger the number, the heavier per given volume of material).

But as mentioned by others, polyester does have some nice properties such as less sag, less absorption of water, etc.

It's too bad they don't make tent/tarp material out of woven polypropylene. PP's biggest weakness is UV degradation–it's more sensitive than even nylon. However, when PP is in it's raw or liquid state, you can add carbon or other additives to greatly improve UV handling properties.

The specific gravity of PP is .91, and it's strength is similar, just slightly less than polyesters. It has a bit more stretch than polyester but less than nylon. It is innately quite hydrophobic (significantly more than even polyester by about 10 times i think).

What one could do, is to make a tightly woven microfiber or near microfiber fabric, and then overlay a thin sheet of non woven PP film on one side and then lightly melt that thin sheet into the woven PP, bonding it with the rest of the PP material and filling in the interstices of same.

Such a material would be light, strong enough, and more important would retain it's waterproofness for a very long time most likely. (I write this kind of stuff hoping a company or manufacturer will take note and perhaps think about applying such ideas).

Lots of interesting info and ideas, thanks everybody.

The big lesson for me is that the weight of a given material has more to do with the thickness of the fabric than the type of fabric. Makes sense.

It seems like most of the commercial gear companies are settled on lighter silnylon and cuben right now and that part of that has to do with availability. Poly does seem to have some advantages… I guess that's what MYOG is all about. Initially I just wondered if anyone was making a flat tarp out of the same material that my family tent fly was made of… I can't imagine it would be too heavy for practical use. Seems like Oware is doing something similar with it's 70D nylon… not sure how this would feel compared to the poly.

Cheers

specific gravity doesnt really matter with fiber as a 30d nylon and 30d polyester weigh the exact same. The polyester fiber would be finer than the nylon fiber of the same denier. As far as strength goes. Polyester is sually stronger than most nylons. Especially when wet and after exposure to UV. Nylon has good elongation which gives it better tear resistance but also makes it sag when wet. A polyester coated in silicone would be a much better tent material than nylon.

Good read on nylon and polyester properties, in this case comparing thread.

http://www.thethreadexchange.com/miva/merchant.mvc?Screen=CTGY&Store_Code=TTE&Category_Code=Nylon-Thread-Information

http://www.thethreadexchange.com/miva/merchant.mvc?Screen=CTGY&Category_Code=polyester-thread-information