Sil-nylon tarps

[Paul_B]

Does anyone know if sil-nylon tarps lose their waterproofness with time? My tarp started dripping on the inside in quite a few spots right across the tarp that made me think it was less about the condensation than it could be the rain coming through. It was very wet but there was a strong wind so it should have blown a lot more of the condensation away before it condensed on the tarp.

Its a two year old Kathmandu trekking Basha from Bison and used to be great. Any ideas?

 

[shaggystu]

i've got a couple of the same tarps (liked the frst one so much i got a second) and i've never had any problems at all. my orignal one is about 6 years old now and has shown no sign of letting water through at all, i'd suggest getting in touch with bison bushcraft to see what they have to say, these aren't cheap products and IMO they should be lasting a lot longer than 2 years in regular use. you could also consider re-proofing your tarp, it's not something that i've tried myself but i believe that the general principal is to dilute some clear builders silicone with white spirits and then spray/paint/dip until your fabric has had a decent soaking then stretch the thing out good and taught and leave it to dry, in principal it sounds very simple to do, what it's like in practice though i couldn't say. good luck

stuart

 

[Shewie]

Once sil gets completely soaked it will allow moisture through, if you're under a tree and drips are landing in the same place everytime then there's a chance it will eventually come through. I get this on my Superfly sometimes, if there's a branch overhead and it's dripping on the same place time after time then I get a fine mist coming through as each drop lands.
You're describing actual drips rather than misting though, are there any seams where the drips are coming through? If there's no seams then try reproofing it.

 

[Paul_B]

Basically my understanding that there is some debate as to what misting is (especially on the US BPL website). Seems misting could be condensation forming or water penetration.

In my case it is water drops (large ones too) that fall from various places. The most common spot was low down where a slight fold appeared which could be condensation rolling down the underneath then dropping off from there. However there were drops appearing all over. I first noticed it when sitting out under the tarp waiting to finish packing up (just the tarp as everything else was packed already for a quick getaway). My waterproofs had dried off when I pottered around before the rain came back and I suddenly noticed fresh, large drops appeared on my waterproofs. Since it was very damp due to being higher up in the clouds and it raining on and off quite heavily. I had been out of my tarp for a bit so condensation from my breathing wouldn't been the cause I think.

Anyway the tarp was sodden and dripping wet. My concern is that I forgot to dry it out properly and it was a bit wet from last time. In fact I pitched the tarp and it was wet from unpacking. I suspect my lack of care has ruined the tarp so I'll have to re-proof.

What about fabsil gold? Does that work too?? Not sure about trusting myself to do the white spirits / builders silicone mix right personally. Builders silicone? Not the mastic kind so what does it look like? In a tin or tube or what? DIY shops sell it at all?