0.9 oz silnylon tarp?

[Scotty Von Porkchop]

Its stopped raining and there's a weird orange circle in the sky.....(hops back on WWOOFing UK )

Well I strung it up properly (ish I couldn't get too tight as it was on a tiny hook) and sprayed with a hose; Its totally waterproof ! I'm rather impressed as its very see through. It does stretch quite a bit though and I think to get any halfway decent pitch it'll need strong tarp tensioners

I was searching last night and I have enough 0.9 oz fabric in my goody drawer to make another, probably two. So do I need to try the grosgrain ridge? an edges too? you know to replace the one I just made that will likely be never used...

[chickenwing]

Great to hear. Glad it holds water.

Btw Here is a link to some useful stitches. http://diygearsupply.com/wp-content/...ing-lowres.jpg

[ntxkayakr]

The one thing about grosgrain I was thinking about is that it doesn't stretch and silnylon does, so is it as good at keeping the tarp taut ? I always just presumed that a stretchy material next to a static one isn't ideal.

IMHO your design is the best, no improvements needed, light and strong. Some stretch can be good however, better to give a bit than to rip in strong winds or falling branches/flying debris etc. I wonder if someone has tested Cuben Adhesive Repair Tape over a hem on a scrap piece of this fabric made into a stuff sack. It might de-laminate after a few seasons and leave a mess due to differential stretch factors. There should be a source in the UK but one in N.A./USA is http://bearpawwd.com/fabrics_misc/fabrics_misc.html
1" wide single sided Cuben tape costs about $4.50 per 18"

More of something a kayaker would pay $$ for to make a custom Silnylon or CubenFiber drybag, than for tarp ridgeline.

[VictoriaGuy]

The one thing about grosgrain I was thinking about is that it doesn't stretch and silnylon does, so is it as good at keeping the tarp taut ? I always just presumed that a stretchy material next to a static one isn't ideal.

Well I strung it up properly (ish I couldn't get too tight as it was on a tiny hook) and sprayed with a hose; Its totally waterproof ! I'm rather impressed as its very see through. It does stretch quite a bit though and I think to get any halfway decent pitch it'll need strong tarp tensioners

I was searching last night and I have enough 0.9 oz fabric in my goody drawer to make another, probably two. So do I need to try the grosgrain ridge? an edges too? you know to replace the one I just made that will likely be never used...

I think that using grosgrain on the ridge or edges of a tarp is a bad idea, for exactly the reason you posted - differential stretch (or lack of stretch...).
Hem a piece of Lycra fabric with grosgrain to get the idea.....

With grosgrain edges and a stretchy/saggy-when-damp silnylon tarp body, it will be more difficult to keep the tarp taut, even with shock cord or latex 'tensioners' in the guylines, IMO. Grosgrain does stretch, but not nearly as much as most fabrics, in my experience.

Not that it proves much, but I've never seen a tent fly (aka 'outer tent') with grosgrain ridge and perimeter, even on very expensive tents designed for rugged use.

[Scotty Von Porkchop]

CW: thanks for the link, I hadn't seen that one.

NTX: cheers, I haven't looked at all into cuben as I'm so poor (everything I make cost virtually nothing )

[Scotty Von Porkchop]

I think that using grosgrain on the ridge or edges of a tarp is a bad idea, for exactly the reason you posted - differential stretch (or lack of stretch...).
Hem a piece of Lycra fabric with grosgrain to get the idea.....

With grosgrain edges and a stretchy/saggy-when-damp silnylon tarp body, it will be more difficult to keep the tarp taut, even with shock cord or latex 'tensioners' in the guylines, IMO. Grosgrain does stretch, but not nearly as much as most fabrics, in my experience.

Not that it proves much, but I've never seen a tent fly (aka 'outer tent') with grosgrain ridge and perimeter, even on very expensive tents designed for rugged use.

Very true.

I am wondering how to neaten up the edges when under tension. Have you any experience with really small hems rolled multiple times ?

[VictoriaGuy]

I am wondering how to neaten up the edges when under tension. Have you any experience with really small hems rolled multiple times ?

I haven't made a whole lot of tarps, but on most rolled (folded, really) hems (and seams) I try to keep the width pretty small (about 1/4"-5/16") because it makes it easier to get around curves (if there is a cat cut, for example) and also because if the hem is double-topstitched it is nice and flat. BTW, a rolled hem with 2-3 lines of stitching is going to be less stretchy than a single layer of fabric, but in practice I haven't yet found that to be a problem.

I've never used a very narrow ('handkerchief') hem on outdoor gear; I don't think I could manage that with slippery fabric.

When I wonder how to properly sew something, I think about (or have a look at) my 1971 SierraDesigns tent -sewn in Berkley, CA- and use that for a model...so nothing very new here!

[Scotty Von Porkchop]

Looking at some of the old kit from western producers sure shows why its better to buy off of the cottage producers rather than the big names.

I was thinking of using a handkerchief attachment (but sightly larger ) to make a thicker rounded fabric tube of sorts. Hard to explain though, I shall try it on some scraps tomorrow

[Scotty Von Porkchop]

Well after hanging (in the brief interlude before the storm) there's some wrinkling and the edges aren't perfect. BUT the fabric seems good so I'm going to make another; as I've loads of really light silnylon left . This time with a proper French seam and no centre ridge-line, I'll try two off to the side and probably a grosgrain edging.

[craige]

Looks good buddy! I've been thinking about the grosgrain options and I reckon without panel pulls, (especially in the rain) it'll be really hard to keep a tight pitch, the fabric will stretch but the edges won't, therefore you'll have sag in the body of the tarp, but taught edges...thoughts?

Hey, if you've got loads of it...