So I just had this idea to make a water bladder from something like polycro... but I wanted to test the idea without wasting all that time. I happened to see an empty subway bag laying on the floor and the light bulb went on!


And all you need to make it is this:


Unfortunately the subway bag already had a pinhole in it before I even started but it proved the idea could work. What I hope to do maybe tomorrow is make a bladder from poycro and use the same closure cap. Basically all you do though is thread the plastic through the hole in the cap, pull it down over the threads on the bottle and then close the cap.

Obviously this thing would be very fragile and only last a few days. The way I look at it is my platypus will eventually break on my thru hike anyway, so I'll just keep making these little puppies as necessary on trail and treat them carefully. I don't really plan to carry water as much as possible so my water storage solution might as well weigh next to nothing.

Use a boxed wine bladder.

Darn, I hadn't thought of that. I suppose those are already polycro or mylar or something huh? Either way I'm still going to experiment with this. I don't drink anyway so no use in buying one of those. I'd also like to be able to have something that I can easily replace on the trail if necessary. In other words I would be able to just find a suitable plastic bag and swap out as needed.

If you asked for them on Craigslist I think they would be free. Thrown out as trash.

True, I probably could do that. How would I resupply them though?

Mail? Restaurants go through major flows every day. Offer to pay postage and you could build walls with them John

Yeah, I just tried a few different ideas with the polycro. They all had flaws. I guess it's not really worth the hassle given the other available options.

The getting from restaurants idea isn't bad either, but again too much hassle. Maybe I'll just start with one of the wine bags and one regular water bottle and only use the bladder for the very rare occasions when I need extra water.

Thanks for the idea!

As far as free and easy goes... is there a reason you don't like soda bottles? tough as nails, available all over the diabetic states of america.

I admire your resourcefulness! But I do wonder how durable a polycro water bladder would be. You may be able to baby one for a few days, but would polycro rip catastrophically, or develop small holes like a Platy would?

I just have this image of the entire thing ripping open in your pack with a full liter of water in it.

Would a small oven roasting bag be more durable? If so you could buy the larger ones and cut them down to whatever size you like.

Mylar chips bag in the same configuration is better.

That oven bag idea is pretty good. I wonder what those are made of. I guess it's time to raid the pantry. Wouldn't be something easy to replace (for free) though.

I don't have a problem with soda bottles other than the weight. Most likely that's what I eventually will end up with. I want the option the carry more than 1 or 2 liters of water in rare situations though. 2 water bottles is already ~2oz, to me that's heavy when I could have some type of bladder that holds that much if not more for half or even a quarter the weight.

I would never trust it inside my pack. I figured on keeping it on the outside only. As far as rupturing a bladder made of any of these thin materials I wouldn't be worried about it. I think the problem is puncturing it. I've used a polycro groundcloth extensively and have yet to puncture it. Keep in mind too that I don't plan on using the thing very often. Only when I need to carry more than 1-2 liters of water. Idealy I'd be camping near a water source every night, that's not totally realistic though.

Good idea on the chip bag. I'll always have one too, I love to bring salty chips and stuff out on the trail. It would be practically weightless just rolled up in my pack until needed. This could be the ticket here, something I will always have the materials to make and light weight. I'll have to test the durability.

Hmmmm, it would be interesting to see how long it survived being dragged on the ground.

Edited by pdcolelli42 on 02/26/2012 07:05:33 MST.

Here was a thread on lightest water bottles where cuben and mylar were mentioned.

http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/34201

You could get the platypus type nozzle from an old platypus or the $1 Office Depot (vapur) or dollar store (chinese knockoff) version.

http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/57295

I read that thread earlier. It mentions cutting the top from a platypus and bonding it to cuben or mylar. That would be ideal, but I'm not cutting my platypus for that and I also have no way of bonding the two. It also seems like another failure point. Any ideas on what to use to bond it that I could readily find?


I'll have to wait till I get a bag of chips to test it out, but I like the idea of using the threads and cap from a soda bottle and just folding the plastic over the threads. That way I can just swap out the bags as needed and keep the top. Who knows though that idea may just be a total failure.

I don't want to sound like I'm dismissing all your ideas, it's just that they don't necessarily apply to my situation. If someone made a cuben platypus type bladder I'd consider buying one if the durability was proven. Maybe someone should start producing something like that. You'd need a supplier of the spouts so you didn't have to go cutting up platypuses. It would be cool fr someone to be able to make any size cuben water bladder you wanted similarly to how you can get custom cuben dry sacks.

Edited by pdcolelli42 on 02/26/2012 09:43:15 MST.

Make sure you round and polish out the bottom of your soda threads as the weight and rubbing would possibly cause some premature fatigue with the slosh of walking...

I've been stockpiling Subway bags for a while, so afraid they will change them and they'll be gone for good. They are very strong for their weight, and compress down to nothing.

They are good for many tasks, from vb socks to keeping fleece gloves dry in the rain. I would only use them to cart water in an emergency...

In addition to bags from boxed wine and coffee, I find these to be light and strong, and trust them inside my pack: < http://www.amazon.com/gp/aw/d/B001E5E0GA>. And as with all reused containers, bring an extra cap, as that will most likely fail first.

Phillip,

Thanks for the idea. I can use it.

Daryl