make your own sil.

[JohnOscat]

have we come to any conclusion as to which is the best non-immersion method to apply the solution? Sponge, brush, rag, etc? Does it make any difference? I'm thinking I'd like to sew my tarp and then wipe the silicon onto it, since there seems to be very little difference in the effectiveness of dunking or brushing, but I'm wondering about how to brush it on.

[Knotty]

I was wondering about those nice brackets myself. I might just have to break out the welder and make a couple of sets... Do you have the dimensions and angle?

Buried in snow right now. but I'm guessing it's about 45 degrees.

have we come to any conclusion as to which is the best non-immersion method to apply the solution? Sponge, brush, rag, etc? Does it make any difference? I'm thinking I'd like to sew my tarp and then wipe the silicon onto it, since there seems to be very little difference in the effectiveness of dunking or brushing, but I'm wondering about how to brush it on.

I'm probably biased but I have a hard time imagining the brushing method being as effective as dunking. I believe dunking with lots of squeezing and shifting of the material within the solution will better penetrate the threads and produce a result that's closer to commercial silnylon. Just my opinion and am always willing to change it based on additional info.

[JohnSawyer]

I'm probably biased but I have a hard time imagining the brushing method being as effective as dunking. I believe dunking with lots of squeezing and shifting of the material within the solution will better penetrate the threads and produce a result that's closer to commercial silnylon. Just my opinion and am always willing to change it based on additional info.

I guess the only question is how well the silicone dissolves in the thinner. If it's not really dissolving, but just being suspended (like flour in water) then the silicone won't travel through one layer of fabric to get to another. If the silicone is really dissolving, or at least going to a small enough particle size that it's effectively dissolved, then as long as the fabric is fully wet, it may not make much of a difference. I can see where the immersion/massage method might break up bubbles that could occur in the gaps between the weave, causing leakage later.

I guess time will tell. Personally, once the weather dries up a bit, I'm going to buy some self-leveling silicone at my local auto-parts store, add mineral spirits and give the "immersion in a bag" method a try.

Realistically, I cannot report out on results as the tarp (DWR + sprayed with silicone "waterproofing" spray) doesn't leak today in our Southern california storms... we just don't get a serious downpour very often.

John

[Knotty]

John - Your analysis is right on. Since the silicone doesn't truly dissolve into the mineral spirits the silicone probably can't soak thru multiple layers of fabric. It probably gets filtered out at some point. Realizing this I did my dunk and squeeze in a 5 gallon bucket. This gave me the room needed to pull the fabric in and out a lot so it all got touched by the raw mix.

[smalls]

Excellent results on my third attempt. The trick I used was to mix a batch with a 3:1 volume ratio, which makes it much too thick. After stirring, if you do it in a clear vessel you'll notice a very large amount of air suspended in the solution as very small bubbles.

The thinner the mix, the less air is suspended, and the smaller the remaining bubbles will be. I gradually added more mineral spirits while mixing fairly sparingly. Once the bubbles were completely gone, I let the mix sit for about 24 hours, and a good bit of the mineral spirits rose to the surface. I poured off the excess, dunked the nylon, and removed the excess with a squeeze, then a sponge. A single treatment made it completely waterproof, even under pressure.

I believe those suspended bubbles are the most common cause of failure. There's no real way to mix the stuff without creating them, and if they're still there when the nylon is introduced, you're apt to get pin holes where ever a bubble adheres to the fabric.

-Smalls

[Jazilla]

Update anyone, Im very interested in this thread.

[JohnSawyer]

Excellent results on my third attempt. The trick I used was to mix a batch with a 3:1 volume ratio, which makes it much too thick. After stirring, if you do it in a clear vessel you'll notice a very large amount of air suspended in the solution as very small bubbles.

The thinner the mix, the less air is suspended, and the smaller the remaining bubbles will be. I gradually added more mineral spirits while mixing fairly sparingly. Once the bubbles were completely gone, I let the mix sit for about 24 hours, and a good bit of the mineral spirits rose to the surface. I poured off the excess, dunked the nylon, and removed the excess with a squeeze, then a sponge. A single treatment made it completely waterproof, even under pressure.
-Smalls

I went to my local auto-parts store and bought a tube of Self-levelling silicone. I broke out a canning jar and mixed 4:1 with mineral spirits, sealed it up, and let it sit for a week to see if it would come out of suspension.

The first thing I noticed is this stuff, being liquid, mixed much easier than prior attempts with normal silicone caulking. After 5 days, it's still a uniform liquid. Flowable silicone, at least, does appear to fully dissolve in mineral spirits.

John

[GvilleDave]

Where in the auto parts store is self leveling silicon? How does it perform as a waterproofer compared to the sil made from caulking?

[JohnSawyer]

I found it in a small tube next to the various colors of RTV... It's designed to seal car-windows and flow into voids to prevent leaks...

People have been using it to seam-seal tarps, thought I'd give it a try. I'm not sure if anybody else has thinned this down for tarp application yet. It'll be a few weeks before I can get my tarp done, I think.


That makes me think: Can I thin down Red or Blue RTV? I wonder what that would look like on a silver tarp... hmmmmmmm....

[Jazilla]

I wouldn't use RTV. It tends to peal off. I used it thinned down to seal the inside of a soft ice chest bag. I had to give it a good thick coat cause the thin coat I started with began to peal off as soon as it was dry.