I just got home and lightly sprayed the tarp......Leaks like a siv.
That's a good point SteveS about the second batch sort of undoing the first attempt. With that in mind, I think that I'd rather just go by a blue tarp (actually a brown & silver). I don't have the time to experiment any more. We're leaving for a conference in San Diego all next week, then the camping trip is the following weekend. Yikes! I need to be sitting in front of the thread injector not the computer.
SCRAPPEDOriginally Posted by Laochri
To do what I was planing would have cost just as much as getting 1.1 ripstop and DIY'n Sil-nylon. For now I am back on the Harbor Freight tarp idea.
Just finished water testing mine. It is slightly waterproof....
I set up a sprinkler to have drops fall on the tarp, and let it run for about 40 minutes. What I found was 2 issues.
The water "misted" into the underside when the drops hit. I understand this can be an issue with sil, but it was more than I expected.
The second issue was that when I hung the tarp to dry, I placed it OVER the ridge-line. This caused most of the sil to leach into the mason line, and now the ridge-line leaks pretty significantly. Not big drops, but a definite wetness passing through the fabric.
So, with these findings in mind I'm going to do the following:
1. Let the tarp dry out from the water test.
2. Cat cut, and re-hem so I can get a tight tarp for drying, and to reduce the amount of sil needed to re-treat the tarp.
3. re-treat the tarp with a second batch.
My plan is to lay the whole tarp out flat, and do the roller method to apply the mixture. Let it set up a bit, then hang it out to dry (UNDER the ridge-line)
<sigh>
I think for the tarp to work it all depends on the thread count of the sheet, and the ability of the solution to fill the gaps. Low TC = leaks Just my thoughts.
I think you are right. I used 200 Thread, which seems pretty wide. I was just looking at some 1.1 nylon, and my guess is that the nylon is not going to absorb the sil mixture so much as hold it between the fibers. Cotton is going to draw in some of the sil, and render it useless. I've seen references to 400 Thread count working well, but perhaps my idea of waterproof, and theirs is different. I've got a down top quilt I don't want getting "misted"
I think this can work, but you need more sil than those of us who failed used.
I still have high hopes for this project, but it's getting expensive quickly.
At this point the only advantage I see is a no-sew tarp with decent coverage.
This weekend as a test I am going to double the amount of sil in the mixture. Hopefully to over saturate the fibers
From what i am thinking it is not absorbing enough if it is 60/40.
Remember cotton absorbs poly blends don't. That may be the issue, the poly blend part is NOT absorbing the silicone, try a 100% cotton sheet and see if that doesn't fix the problem
Just my :2cents:
So I'm curious how Noble's sheet tarp could hold ~5gallons of water, while SteveS' and mine mist and leak like crazy under the lightest of wet conditions? My sheet originally was on the heavy side as far as king size sheets go. I got it at Savers, so I had no information on thread count.
I like the idea of hanging it below the ridgeline as well. I noticed the ridgeline acted like a squeagy (sp?) when I was preparing it to dry.
Rolled out about 3/4 of a batch of sil on one side of the tarp, let it dry and did a water test. It held back the water, and did not mist so this was a success.
I left it set up, and it rained like the dickens last night. We had a bolt of lightning hit close enough to set off an arc-fault breaker in the house. I'm glad I was not out there testing the tarp when that happenedIt was not completely dry under the tarp this morning, but it was close enough that I would have expected to be dry if I was hanging.
So, when re-applying the mineral spirits and sil mixture, it did not seem to "soften up" the first application, and I also tested this by pouring some ms on a bit of sil snot I pulled out of the bucket, and It did not dissolve. So that concern seems to be unfounded. You can re-apply as needed.
It did take almost twice as much mixture to get a waterproof 60/40 cotton/poly as expected. From the "how-to" video posted here, it seems to take quite a bit more than waterproofing nylon seems to, which appeared to be 1/2 batch per tarp?
With that in mind, I'm thinking about the dimensions you can get from Tableclothfactory.com and possibly do one in crinkle taffeta.....
Nice dry spot under.
Looking up through the dry side to the wet above.
Rolled out top coat of Sil darkens the fabric color even more.
Ready to roll!
Couple points here. Mine did hold back water. I filled it up with a cup or so in the sink, and it did not leak through. It did however mist quite a bit when I hit it with the sprinkler hose. A second rolled out treatment of sil fixed that up.
As you said, hanging the tarp under the ridgeline to dry prevents the sil from being squeegee'd out. On my first attempt, that is what caused the major leak at the ridgeline.
I tend to hang my tarps under, but even with 5" cat-cuts on this one it's hard to get it tight. I might have to hang it over. I hate doing that since it can create a drip channel right down on top of your head.
This project is a step up from the blue poly tarp, but it's no professional level hangers equipment either (which was my hope....)
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