Membrane sil poly/SU4000 ?

**BillC523** · 02-11-2016, 20:28

Greetings! It's my understanding Membrane sil poly weigh's in at .93 oz. per yd., whereas SU4000 weighs 1.07 oz. per yd. finished. My question is what would one of each weigh if it were similar to the Supperfly or Old Man River tarp. Assuming someone has made one of these around those assumptions. Also, i'm more interested in the footprint it makes in the pack? Grapefruit size, or?

**Randerson** · 02-11-2016, 22:47

I just finished an 11 footer w/doors in the PU4000. Weight is 14.8 oz. Will compress down close to size of a large grapefruit/small melon20160210_165115.jpg 20160210_165147.jpg

**BillC523** · 02-12-2016, 16:47

That's a good looking tarp! How did you layout the pattern?

**Liberty Guy** · 02-12-2016, 16:53

do you mind sharing the actual dimensions?

**Randerson** · 02-12-2016, 17:41

Thanks Bill, I've got a pattern that I've come to thru some trial and error. If you plan to diy it, check out the pattern and fabrics available from Scott at DIYgearsupply.com, or the tarp kit from ripstopbytheroll. The fabric starts at 58" wide, so I think comes in finished probably 6 inches narrower than a superfly?

Liberty guy, see comments above. My finished tarp is 132" ridgeline and sidewall are roughly 56"(minus 3"Cat cuts between tie-outs) hope that helps.

**Helium33** · 02-13-2016, 13:16

That's a good looking tarp.

**SpitballJedi** · 02-22-2016, 07:41

Does Silpoly need cat cuts? Or can I just leave it straight?

**Caminante** · 02-22-2016, 07:47

Originally Posted by SpitballJedi

Does Silpoly need cat cuts? Or can I just leave it straight?

Word on the street is that silpoly does not need cat cuts. I did a silpoly tarp w/cat cuts and based on the really minimal stretch of this fabric I would not do cat cuts again. It pitches taut and is taut the next morning, even after rain or dew.

I'm currently about 60% finished with a MEMBRANE silpoly tarp (12' winter) which I chose not to put cat cuts in. Kyle recommended a slight cat cut in this material in another thread, but I'm convinced enough by the silpoly to give it a shot with straight cuts. Somewhat burdensome to cut and re-hem later if I find I really need them, but I'll take that chance.

**SpitballJedi** · 02-22-2016, 08:11

Thanks for sharing.

The cat cuts seem like a PITA to cut. That's why I asked. I don't have a lot of space, but I think I could handle a straight cut on the living room floor.

**HammockHokie** · 02-22-2016, 08:22

Cat cuts are not that bad to cut. I just finished a tarp out of Xenon and I put 3" cat cuts in it.

I used a trick I read somewhere to tie a piece of line on a set of tent poles to form the curve. Worked pretty well and only needed around 8ft of floor to lay it out.