Waterproofing unknown water resistant fabric

[lmoseley7]

I purchased some fabric of unknown origin from Hancocks probably back in 2012 because it looked like it might shed water. I first tested it by gathering it up into a ball and filling with water; no leaks. I then squeezed it and forced leaks, but I figured rain wouldn't be that forceful. The next test was stretching the material out and standing underneath the valley of my roof where the rain pours down during a pretty heavy rain; no leaks.

I really liked the idea of using this material because it was so lightweight. This past Monday I finished up a hex tarp with a 12' ridge and about 10' wide. With 6 D rings and grosgrain attachments it comes in just under 13 oz. I did an impromptu hang in the yard to test it because it was raining that afternoon. The rain wasn't really heavy, but constant throughout the afternoon. After several hours I went out to see if there were any leaks and I found a couple of places along the ridge where some water had formed droplets. I don't have a ridge seam, I did one seam on each side so that I wouldn't have to seal the ridge, so that's not the culprit.

Now I'm trying to figure out what would be the best way to reinforce the waterproofness of the ridge. I'm pretty sure I'm not dealing with silnylon. I'd like to coat about a 6-8" strip down the middle of the ridge as the rest of the tarp seemed to shed or bead up the rain very well. Obviously I could go the silicon mineral spirits route, but I was hoping for something less messy. Also, since I'm not wanting to do the whole tarp, it wouldn't be worth the materials. Anyone have any opinions on sprays that might be worthwhile? Not knowing the type of material, I'm not sure what will stick and soak in vs. what will just flake off. I don't want to spend a lot to find out it doesn't work.

[VictoriaGuy]

Was the tarp hung over a ridge line, or suspended 'from the ends'?

A way to 'accelerate aging' a bit would be to (gently) hand wash your tarp to simulate some use and see if the leaks stay the same or get worse.

You are wise to test in the back yard - a cold rainy night in the bush is the 'wrong time' to find out you have a problem!

[lmoseley7]

Was the tarp hung over a ridge line, or suspended 'from the ends'?

A way to 'accelerate aging' a bit would be to (gently) hand wash your tarp to simulate some use and see if the leaks stay the same or get worse.

You are wise to test in the back yard - a cold rainy night in the bush is the 'wrong time' to find out you have a problem!

I hung the tarp from the ends but with a ridgeline. It's just the ridgeline was not under the tarp. This was a really quick hang as it was raining and I don't have a set place in the yard to hang a 12' tarp. I was thinking if I ran the ridgeline under the tarp the ridge might be a sharper bend, which could help with the rain rolling off. As it was, the ridge was more of a curve than a sharp bend. I left the tarp up overnight and through the next day so that it would be dry when it was put up. I'll test it again the next time it rains on a day when I'm home to see if I have similar results or if it has worsened. I'll also try to mark the areas that leak so that I'll know if any treatments are working. This thing is just so light compared to my other tarps (DIY and Gear Guide) that I want it to work badly. If nothing else, this would be a good wind break for winter camping when rain isn't in the forecast.

[lmoseley7]

I ended up buying a can of scotch guard from Walmart to try sealing the tarp. It was around $6 so no huge loss if it doesn't work. I don't get out but once or twice a year right now which prevents me from spending too much money on gear, although I would love to have a 6-8 oz cuban tarp and lightweight backpack. For now I'll just have to make what I have work. If anyone has any suggestions for specific products they've used in the past I would appreciate it.

[DavyRay]

The best recommendation I have is McNett products.

http://www.mcnett.com/gearaid/waterproof

[lmoseley7]

The best recommendation I have is McNett products.

http://www.mcnett.com/gearaid/waterproof

Thanks for the suggestion. Their products look great and website includes a lot of info.