What defines Waterproof material?

**leftheavy** · 08-21-2009, 15:21

I am new to the hammock camping scene, but I've built my first hammock and now I'm lookingfor material to make a tarp. Haven't found any Silnylon yet, judgin from the descriptions of the material I've seen. I have located some rip stop material that is very difficult to suck air through so I took a swatch home. Water poored off the swatch, but ran through when under pressure (holding the swatch up to the faucet tightly). So I dried the material and sprayed Silicon waterproofing on it. The next day I tried it again. Vast improvement but water still came through under pressure, albeit much, much less. The material did wet when I did this, but water still beeded on the surface.

So how good is good enough? Can you siliconize quality regular ripstop enough to make a good tarp? I don't have enough field experience to answer this.

One last question: The bolt of fabric said "Unit weight 0.65". Any idea how this translates into oz/yd?

**warbonnetguy** · 08-21-2009, 17:07

try it a couple inches under the shower head instead, doesn't sound like it's waterproof though.

**Dutch** · 08-21-2009, 18:08

Originally Posted by leftheavy

I am new to the hammock camping scene, but I've built my first hammock and now I'm lookingfor material to make a tarp. Haven't found any Silnylon yet, judgin from the descriptions of the material I've seen. I have located some rip stop material that is very difficult to suck air through so I took a swatch home. Water poored off the swatch, but ran through when under pressure (holding the swatch up to the faucet tightly). So I dried the material and sprayed Silicon waterproofing on it. The next day I tried it again. Vast improvement but water still came through under pressure, albeit much, much less. The material did wet when I did this, but water still beeded on the surface.

So how good is good enough? Can you siliconize quality regular ripstop enough to make a good tarp? I don't have enough field experience to answer this.

One last question: The bolt of fabric said "Unit weight 0.65". Any idea how this translates into oz/yd?

I doubt it is .65 oz/yd That puts it in the Cuban fiber catagory. There is a ggod thread about adding silicone to make ripstop waterproof. Honestly though tarps are a lot of work. I would just invest on good Sil that I know will work. You are still saving money. Just my opinion though.

**Spock** · 08-21-2009, 18:14

Until you learn to ID waterproof stuff, you are safer ordering it:
http://www.owfinc.com/
http://owareusa.com/fabric.html
http://www.speerhammocks.com/Products/Supplies.htm
http://www.seattlefabrics.com/

**warbonnetguy** · 08-21-2009, 19:05

www.questoutfitters.com has some really nice olive grey sil in stock.

**Merganser** · 08-22-2009, 09:50

I'll add one more source to the list Cooke Custom Sewing.

**Jodster** · 08-24-2009, 09:13

I'm kinda in the same boat. I have a fabric store that has a good selection of rip-stop, but the employees don't seem to know what sil is.

They do have nylon that is shiney on one side ..... would that be sil?

How long would you hold it under the shower head to be confident that it is water-proof?

**leftheavy** · 08-24-2009, 18:55

That sounds like the material I have seen. The shiny side is "calendared", which means they pass it through heated rollers to bond the fibers together (althogh it still unravels). I was wondering if calendaring has any effect on the strngth of the material.