DIY tarp help needed

[berk]

I attempted the DIY sil treatment on two tarps I had made, both with 1.1 from Magna (one was the coyote brown, which is extremely thin, and the other in the USMC camo, “normal” thickness). Used two quarts of low-odor mineral spirits, and a tube of 100% clear silicone. Got it mixed up good, soaked/squeezed/soaked/kneaded/soaked/etc. until everything was saturated. Hung it for a few days. The thin coyote one has never fully cured, as far as I can tell – still tacky several months later. Once they were dry, I tried a bit of a hose test, which they both passed. However, I took the camo one out for a trip, and the near-constant rain soaked through it after a few hours, wetting everything underneath (including my down UQ!).

Trying to figure out what to do with these. Do I re-apply more DIY sil? Maybe mixed thicker and brushed on? I have some “Tent-Sure” from McNett (PU for re-coating tent floors), could try that as well. At this point, just trying to prevent these from being a total loss, don’t really care about weight all that much since I have a Superfly for backpacking, and these would just be car or winter campers. Let me know what you think!

[MAD777]

Don't use tent-sure, it won't stick to silnylon. When you applied the silicone, did you pitch the tarp tight and force the silicone into the weave of the fabric?

[berk]

No...used a "dunk and squeeze" technique until they seemed saturated, then pitched them to dry. Thanks for the info on TentSure.

[berk]

Would a re-application of DIY sil be in order? Pitch taught, then brush on (maybe a bit thicker mix this time?)

[zooshooter]

Would a re-application of DIY sil be in order? Pitch taught, then brush on (maybe a bit thicker mix this time?)

I second this idea. I saw a website earlier today that was touting the dunk/squeeze method of application and all I could think to myself was "That will never work" because then (assuming you stretch it out to dry) the sil mix won't necessarily maintain surface tension between threads and can pop like a bubble leaving you with holes in your tarp. Pitching and brushing on is always the best option in my opinion.