Cat tarp out of DIY sil

Nice experiment. It will be interesting to see what the weight is and how waterproof it is.

The ultimate test of waterproofness, would be to put something that absorbs water, like a sleeping bag, touching the inside of the tarp.

Maybe what you did is easy for a MYOGer, but difficult for a manufacturer – waiting for it to cure, evaporation of mineral spirits into the atmosphere…

Interesting. I'd think it would be hard to match the waterproofness and/or weight of commercial-grade silnylon. Maybe you can convince Richard Nisley to measure the hydrostatic head of a sample.

I agree, it would be hard to beat pre-made sil. Like I said, this was just for fun.

I got the idea from this monster thread over at hammockforums https://www.hammockforums.net/forum/showthread.php?t=2011

People have reported both good and bad results over there, some achieving weight results similar to pre-made sil (i.e. 1.4 oz using 1.1 ripstop)

and what did they report for water-proofness?

Results varied based on method. Most of those who sewed the tarp first then brushed on the sil (what I chose to do) reported that their tarps passed a hose or shower test just fine. Some of those who dunked their tarp in a bucket of sil and massaged the liquid into the fabric and then hung to dry/cure reported that there were spots of misting when hosed down (probably caused by residual air bubbles). Others tried spraying it on, and I don't think anyone had good results with this.

Daniel, do you remember if anyone in the hammockforums thread tried airbrushing? I have wondered about that. I'll go read through the thread myself if you don't recall.

Colin – do you mean out of a paint-type sprayer? If so, I think people tried that and I don't remember them having good results.

I took the tarp down today to weigh it and the sil added 2.9 oz to the tarp. I'll check how waterproof it is later sometime.

I meant a little airbrush, but that probably hasn't been tried because it would take a while. I've sprayed silicone onto small pieces of fabric with my airbrush and it works well. It is very controllable and a thin, uniform coating is fairly easy to achieve. A paint sprayer is similar, but it would spray a much larger volume of fluid in larger droplets.

Nice work on the tarp. It looks great and, given the weight, it sounds like you managed to apply a pretty thin film of silicone.

Yeah I don't recall anyone ever trying an airbrush… Might be worth a shot if you could get good penetration into the fabric, but like you said, it would be very time consuming.

What's the dimensions? I made my own with the same materials, mine's approx. 10 x 12 (thinking about trimming it down) and w/ tie outs and guy lines weighs in at just over a lb. I did the "dunk" method after sewing, and it's completely 100% waterproof – the first night out it survived a torrential hour-long downpour.

Glad to hear yours is water-tight! I still need to test mine. It is about 9 ft long, about 68" at the head end, and about 48" at the foot end. With zing-it lines and the stuff sack it weighs 12.7 oz.

Did you seam seal the ridgeline after the sil treatment?

Just an update – I finally had time to check to see if the tarp resisted water, and it passed a vigorous 5-minute hose test today with flying colors! No water penetration or misting anywhere that I could feel.