patch PU drybag

[Gadgetgeek]

So on my trip, one of my sealline storm sacks got some scuffs during the rock hopping. (lessons learned) anyway, they are minor enough that I think they could be fixed just with some coating (although I could glue some fabric over them) Anyone got any good/cheap methods for patching PU coated nylon? my understanding is that silicone won't stick well to the PU.

[icefest]

Either aquaseal or seamgrip. Both will stock well.
Clean the areas well beforehand.

I'd probably glue them from the inside and impregnate a piece of nylon against it.

[Gadgetgeek]

Any of the big boxes carry those? from my looking, shipping kills. I've been trying to find tear-aid for a vinyl bag, and have not been having much luck.

[Moondog55]

Marine shops for High Strength vinyl glue
I've never had a problem using neutral cure silicon on PU proofed fabric

[walkon]

Fishing tackle stores usually stock aquaseal

[icefest]

Diving stores also sell aquaseal. Seam grip is sold in outdoors stores.

[Gadgetgeek]

So far my local rays, anaconda and bcf don't have, have to hit kat and MD, and a couple independents. I've got some silicone, at the very least I can patch from the outside. I'll hit the surf/dive stores, I'm sure there are a few here. I tried pool shops for vinyl patches, but they didn't have much.

[Gadgetgeek]

tried thinned silicone for a patch, total failure. The silicone just peels off once cured. not sure if its a thinners problem, wrong silicone(selleys glass), the ratio I'm using or what. no bonding to either the nylon of the patch, or the bag. any ideas?

[Tex]

Any of the big boxes carry those? from my looking, shipping kills. I've been trying to find tear-aid for a vinyl bag, and have not been having much luck.

Can get tear-aid in eBay.

[Gadgetgeek]

Yeah, might have to, I have a few stores to hit tomorow morning, and if those turn up dry, I'll have to order. Unfortunately stores on the sunshine coast don't seem to be bothered with not having websites.

[icefest]

tried thinned silicone for a patch, total failure. The silicone just peels off once cured. not sure if its a thinners problem, wrong silicone(selleys glass), the ratio I'm using or what. no bonding to either the nylon of the patch, or the bag. any ideas?

Its a glue vs surface problem. Silicone and PU don't mix. Its like using a nut that's too big for the bolt.

[Moondog55]

Icefest I have never had that problem
When I repaired my Thermarest leak; neutral silicone was the only glue that worked, as a glue tho I did not dilute it
I wonder if this is only a problem with acetic cure silicon?
Gadgetgeek did you clean the surface with Shellite or alcohol before trying to glue? I find it's more often not having clean surfaces to bond that makes the difference

[icefest]

Your thermarest doesn't have the sheer flat pu surface. Of it's an old model it's probably polyester with no glue on the top-for comfort.

[Moondog55]

Researching this
I found an interesting link for medical applications

http://nusil.com/services/downloadmedia ... load=false

http://www.adhesivesmag.com/articles/85 ... -adhesives

[Nuts]

Aquaseal is great for open-to-air cure. As far as I know, a 2 part urethane adhesive is the strongest bond for patches but not a cheap fix. Isopropyl Alchohol (edited) for cleaning, aussie metho is a relatively pure cleaning agent as well.

[Gadgetgeek]

Yeah did my cleaning with metho, it might have some coating on the outside, I'm not sure. I's also wondering if its a thinners problem, I'm using mineral terps, shellite might be better, but I'm concerned that might degrade the rest of the coating.
Anyway, got a seam-grip kit at BCF for far too much, but thankfully I only need little dabs, and the patches will come in handy for other stuff. from the smell, seam-grip is a toluene based glue, so it should air-cure just fine. I'm pretty much just brushing it over the scuffs, since its just pinholes.

[Nuts]

Let's know how it goes if you do use a patch. Just to say that the tear-aid patches (Tex mentioned) work well for non-porous surfaces. I think the glue (ie. glue spots supplied with T-rest) are to fill the weave in the coarse fabric finish mats. If it has a slick coating, such as the white PU inner lining on S2S dry sacks, duck extreme tape works well for patching.

[Gadgetgeek]

I'm going to do a fill test today, but I'm pretty confident that its all good now. should be pretty permanent, seems like its bonded right into the fabric. I get the feeling the tear-aid patches are more of a semi-permanent field solution rather than a long term fix. but they will be handy down the line. Now to fix the vinyl bag. tempted to try pvc plumbing glue, but I still need a patch material....

[bluewombat]

I used to make pvc skin kayaks so have had some practice with this stuff, not much sticks to pvc. Plumbing glue is essentially a solvent and in my experience does not work well on PVC material, you can buy specific pvc fabric glue (Ferrari is the brand I am familiar with) but it is not easy to find and it is not cheap. Any old bit of PVC fabric you have around will do for your patch if you go down that path.

Last edited by bluewombat on Fri 12 Jun, 2015 12:06 pm, edited 1 time in total.

[Gadgetgeek]

Yeah, I kinda figured. I did find a MEK/Toluene based solvent glue and it seems to have worked, although the patch is stiffer than the surrounding material. But that may be more due to the fact that I did a double patch,(inside and out). It seems very functional. Feels good to keep gear in use.