Bushwalk Australia

So, the Kathmandu PU coated pack liner I've been very happy with for a long time is finally leaking a bit. The tape sealing on a bottom seam is failing in a couple of spots. Of course, they don't make them any more. Can't find them anywhere else. Not sure what capacity - probably 50L. It's tall, not squat, which allows me to slide the tent down beside it after I've packed most things, if I'm packing up in the rain. I've tried dead dog bags and garden bags, but I find they need replacing often, and don't have the benefit of being the right shape for my purposes.

Would silicon on the outside of the seams work??? I'd rather leave all the tape on as extra insurance. Or is there something else I should use?
Ta for your thoughts.

YES to the diluted silicon painted on the outside

You can pull of the Tape as it will be next to useless.

Reseal the PU coated fabric seams with Gear Aid Seam Grip
http://www.paddypallin.com.au/gear-aid-seam-grip.html

If wanting to reseal silicon coated fabric Gear Aid Sil Net is best
http://www.paddypallin.com.au/gear-aid-silnet-28g.html

Silnet is simply diluted roofing silicon, why spend money you don't need to?
For less than $15- I can make 2 litres of it and any excess diluted silicon will penetrate the seams and reseal the tape in my experience. You only dilute enough for immediate use.
I use a 50/50 mix of Shellite and mineral turpentine for the rapid dry time, 150 grams of the cheapest roofing silicon to 500 ml of solvent. The same as Franco does

Seam Grip will stick better but if you dilute the silicone as Moondog explained it will work by saturating and expanding the thread.
It will not work if you coat the stitching because it will peel off with abrasion.
BTW, even doing siliconised tent fabric , do not coat , for the same reason .

Franco wrote:Seam Grip will stick better but if you dilute the silicone as Moondog explained it will work by saturating and expanding the thread.
It will not work if you coat the stitching because it will peel off with abrasion.
BTW, even doing siliconised tent fabric , do not coat , for the same reason .

Thanks for your thoughts, folks.
Franco, I'm not sure what you mean - what's the difference between saturating the thread (which works) as opposed to coating the stitching (which comes off)?

I think where most people come to grief is in not cleaning the area to be sealed properly. Clean with a decent solvent after washing all the dirt and grease off with a mild soap and warm water. I use a mix of metho and isopropyl and Shellite simply because that is a mix I use on electronic components and I usually have a bottle in stock and you only need a very small amount.
It is the cleaning step most people forget or regard as unimportant

Tortoise wrote:

Franco wrote:Seam Grip will stick better but if you dilute the silicone as Moondog explained it will work by saturating and expanding the thread.
It will not work if you coat the stitching because it will peel off with abrasion.
BTW, even doing siliconised tent fabric , do not coat , for the same reason .

Thanks for your thoughts, folks.
Franco, I'm not sure what you mean - what's the difference between saturating the thread (which works) as opposed to coating the stitching (which comes off)?

The silicone is meant to soak (penetrate) into the thread . If it is too thick it will just sit on top and then can be scraped off with abrasion.
But it is very important ,on repairs, to do as Moondog commented, clean the area first because any dirt or grease will prevent the sealing from working well or at all. You should not need to do that on a new item.

I've had silicone not bond at all to some PU coatings despite doing everything to make it do so. I'd recommend seamgrip, just because it has the best chance of success.

Yet I have done it many times with success mostly and I put down the failures to not cleaning properly

There are lots of chemicals in the world, maybe there were other factors at play, potentially DWR coatings, or the like. Although the good thing with silicone is it tends to be an all or nothing sort of deal, either its stuck on, or just peels off, so its clear if it worked or not.