when silnylon fails, what to do?

[turk]

thank you all for input.
I guess its live and learn . Have be less hard on my gear.

bah .. no worries eh

Allow me to pose a question then while on this topic... If you wanted to make a tarp to stand up against heavy snow fall.. snow piling up on a heated tarp, and refreezing. Thats alot of weight. What other fabrics should I be looking at?

I have an order for 1460uv soft structure tyvek. It won't go to waste. But should I be considering something else to handle higher water pressure?

Does anyone know a fabric with good water resistance under fairly high pressure?

[Just Jeff]

Neo's tarp is heavier duty, and I bet it's got higher water resistance.

Re: touching a sil tarp, I think that only happens when something is pushing against sil with a lot of pressure. Just brushing against it shouldn't cause the water to come thru the tarp. But it will cause any little droplets of condensation to collect into bigger drops and start running down or dripping.

Sometimes, when this condensation is on the underside of the tarp, the wind can blow the tarp and shake the condensation off...this feels about the same as misting. Some folks think sil doesn't actually mist, and that people mistakenly call this condensation misting. I think both happen.

[blackbishop351]

Re: Neo tarp. One of the reasons I stopped using mine - this was during a test after I'd made my first BlackCat - is that I noticed the coated material didn't shed water like sil does. In fact, in some spots near hems/seams, it appeared that water was soaking INTO the material. Not coming through underneath, mind you, but waterlogging the tarp material itself. Not good (in my book anyway) when the tarp already weighs 1.5 lbs.

[slowhike]

.Sometimes, when this condensation is on the underside of the tarp, the wind can blow the tarp and shake the condensation off...this feels about the same as misting. Some folks think sil doesn't actually mist, and that people mistakenly call this condensation misting. I think both happen.

i believe you're right. i feel sure i've seen both.
an observation about the silnylon for turk... this past winter when blackbishop & i were out in linville gorge, i made the mistake of leaving water in the silnylon water bag i had bought from dancing light gear.
it froze near solid. fortunately it had some unfrozen in the center & before breaking camp the ice freed it's self & fell loose.
but next time i put water in it, it had multiple pin holes slowly allowing drops of water to form on the out side & run down the side.
so it seems to me that the water froze with in the fabric as well, causing damage to the sil.
of course water freezes on sil all the time in the winter w/o causing damage, but i suppose the extra pressure of the gallon or more of water helped force water into the sil to freeze?
but i don't suppose that would be the case w/ the heated tent, unless the heating & cooling would some how cause water to penetrate the sil, then freeze when the stove goes out<g>.

[turk]

Thanks slowhike, you've hit home precisely. Everything I am trying to work into the design of this tarp is so I won't have some crucial flaw and have to do it over. I hate blowing time and effort on something that might leak, because I missed a design element.

My worry with the tarp, is the cycling of a wood stove. Just after the stove goes out, I will have rapid ice build up, followed by rapid thaw every morning, when the stove fires up again. 100 deg. temp diff from underside to top, and 300+deg diff, from stove jack fabric to sil.
My concern is the freeze-thaw cycle daily, and the weight of ice pushing on a lightweight fabric.