in my past travels i have come across a item of kit called a millbank bag its used to fillter water before adding tablets or boiling. its made of tightly woven canvas fabric and looks like a big sock. sure its low tech and slow but it works well ,does not clog or break. the bag works this way simply fill to marked line on bag squeeze to soak and then let drip into cup or water bottle add your tabs and your good. to clean shake out dirt let dry and you can use it again and again.our brit and aussie friends know what this is as it is a brit item..

Mill bank bags are a good bit of kit, they filter out gross contamination very well and allow a puritab to do its job more efficiently. The bags come in 2 sizes, 4.5 litres for individual use and 22.5 litres for groups.

Can you post a link or vendor? I use cheesecloth now.

Would this be something that could be home made? Is it just canvas or special cloth that looks like canvas?

Thanks,
Neal

For those that were wondering, the Millbank bag:

Imagine a canvas windsock that doesn't have its end open. Fill with water and allow to seep through. Seep is the word; it removes all the fine particles, but these block the very holes the water should go through. Having spent about ten minutes trying to hold one of these over a small bottle opening is not my idea of fun weight training: more like wait training!

Check out www.silvermans.co.uk product 34969

Reading from my water supply pamphlet it states the bags are made from "stout green chain weave cotton" so not as thick as canvas.

Yeah, these look very useful, but they cost a lot for what they are. Nomad Travel Store sell these. I just recieved a sil nylon tarp that i ordered from them for only £30. The service was excellent. I ordered it by post with a check and an order form. It took one day for them to recieve the order and I recieved it the next day. I supose this is really down to the great service that the royal mail provide but it is also down to them sending the order off instantly. It said to allow for 10 days delivery <img src="images/graemlins/grin.gif" alt="" />. The tarp is good too. It can be poppered together to form a bivi bag and it has lots of loops and eyelets. I'd recomend Nomad travel store. I don't know if they can deal with international orders though.

Unfortunatly the Nomad website is down!- At least the link supplied is.
Joblot

How much does the Millbank (or other canvas seep bag) weigh?

1. To filter out large chunks of sediment, the material in pantyhose works as a pre-filter. For best results, use multiple layers. You get good flow rate through the material.

Pantyhose also works well as a mesh bag for keeping food cool in stream or lake. Can be made into bug-netting. Lots of uses. I recall reading somewhere that they also work well as bottom liners to keep your hiking pants from binding on your legs, but I haven't tried that trick myself yet. Their mesh construction should let them work like a thinner version of mesh underwear (ala Wiggy's mesh nylon tops & bottoms).

2. To filter finer chunks of sediment, why not carry a few paper coffee-maker filters? They cost next to nothing per filter, are lightweight, and can fold up small enough to fit in the corner of a pocket. Plus, being made of paper, they are multi-functional.