Lightest Silnylon

Sea-to-Summit sells "Ultrasil Nano" dry bags that are substantially lighter than the 'regular' silnylon version. 1.0oz vs 1.4oz in the two 15L size I have. Consider that the clips and rolltop are mostly a wash, so that savings is mostly material in a very small bag. You might ask them for a material spec. to start source research from. I highly doubt they'd sell you some but it wouldn't hurt to ask.

The ultrasil name pops up on Quest list from time to time, but I don't know of its weight or if its the same stuff. They are worth a call, I'd be surprised if you didn't walk away with a lead or two.

I guess its possible to coat your own, from lighter base materials, too. though I'm far from the person to help you there.

Let us know!

StoS also makes a roughly 5by8 tarp of the same material, with a reported weight of just over a half pound.

Terra Nova makes a sil tarp of similar size with a reported weight of just over 6 oz.

In any event, Prolite Gear no longer sells that smaller tarp, but sells the same material in an 8by10 T-N tarp: http://www.prolitegear.com/terra-nova-tarp-shelter-2.html

The material is rated at 3000mm HH, and is a mini-ripstop; however I've not yet tested it for sag – waiting for more springlike weather.

Not to be deterred, purchased the smaller T-N tarp when PG had it, and stripped out all the seams (no grommets). The weight of the material came out at 1.147 oz/sq/yd. It is an expensive way to get the material for MYOG; but so isn't best quality Cuben. T-N also makes an even larger tarp of the material for 3 persons. As you buy larger tarps, the price per yard of the material obtained comes down, so long as you need that much of it for the project. T-N does not state the denier of the tarps, but IMO it would have to be in the 15-20D range. One possible drawback, the color is a darker green that you might not want for a shelter.

Hope this helps.

Samuel,
Using an educated guess, it appears the Silnylon I've found is the same one Terra Nova are using. It's listed as seconds on the re-sellers website so I assume the re-seller buys in the stuff that Terra nova have rejected. As the re-seller describes it as follows "This fabric is 2nd choice because the hydrostatic head doesn't meet the requirements for expedition use. For all other projects it's still very good choice and waterproof."

Are you looking on extremtextil?

Which of their silnylon's were you hoping was a similar one to T-N's?

Aside from that, you may find this link useful when having to compare weights in Europe to things mentioned on this website:
http://www.ginifab.com/feeds/ozyd2_gm2/

Ben, It's the 40g/SqM sil at extremetextil that must be similar to the lightest stuff TN use. Especially as Samuel's weight comes puts TN sil at 38g/SqM. so allowing for any error in measurments they seem very similar- especially taking into account colour.

I bought some of the 65 gsm 40D sil from them and the quality doesn't look like "2nds" at all to me, feels great.

I've made my first flat tarp from it and it feels nice, I think you might be right about the lighter stuff being the same as T-N's.

When my sewing skills have improved, I'll be moving up to the 40gsm stuff. Next I'm using 1.4oz 2nds from diygearsupply but I'm not actually sure what to make!

Diygearsupply.com has some 1.1oz-1.2oz 15d silnylon at $8.95/yd. I have no experience with this fabric, I just know that it's out there.

Ryan

Folks,
Could not count on fingers and toes the number of threads here that have dwelt on silnylon 'bargains.' There was a very long thread here a few years ago about whether any silnylon could be purchased in the USA that was very waterproof. For years, I was buying silnylon from many sources in the USA and sending it to Roger Caffin for testing. None of it was even half as waterproof as the Terra Nova at 3000mm HH. Finally, Roger and I just kind of mutually gave up on looking.

Then came the material currently sold by Thru-Hiker and tested by several, with results posted on this site, that was also in the 3000mm range. I believe the Terra Nova specs because of the reputation of the company, but I still would not use the material for a tent without first testing for HH and sag. Should add that when I measured and weighed it, left out half inch folds at the edges, so the actual weight is closer to 1.1 oz than 1.15 oz. Sorry about that. I find that .0295 is a good multiplier for converting grams per sq meter to oz per sq yd.

Please do not rely on claims about waterproofness or fancy labels like 'ultrasil' or 'shield,' or anything else unless a HH figure is specified, and even then, consider both testing and the supplier. It just doesn't make sense to put in the amount of time and effort needed for a MYOG tent without knowing that the material is the best quality. When you have to camp in an exposed location, and the heavens open up, you won't be sorry.

Anthony – I used 50g/m silnylon from extremtextil to make a tent (http://www.backpackinglight.com/cgi-bin/backpackinglight/forums/thread_display.html?forum_thread_id=46644). As I recall this was also described as seconds and yet it has proved to be very waterproof. Richard Nisley tested it for HH and it came out very well, search for results posted in his HH testing thread. And in the real world, we survived an alpine thunderstorm with no water penetration at all. Based on that, I would buy from extremtextil again.