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Light and Easy Water Filtration for the Lazy Backpacker


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Home Forums Gear Forums Make Your Own Gear Light and Easy Water Filtration for the Lazy Backpacker

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  • #1431942
    Kyle Purcell
    Member

    @dufus934

    Locale: North Texas

    This is awesome! How did I miss this? I've got to make one of these, thanks for the post!

    #1615205
    Glenn Tober
    Member

    @glennt

    All of the posts on this subject have been very inspiring. Let me add one improvement. I recreated the equivalent of this project using only the filter, the Walmart bag set and a few dollars in extra home supply parts. In doing so, I eliminated the need to make any modifications to the filter cartridge, so if you take this approach, you don't have to grind off any threads since this method uses the Katadyne filter without modification.

    I discovered that pieces from a common schedule 40 2" PVC pipe and slip end cap, sliced into a ring set, are ideally sized to replace the Nalgene water bottle parts. In practice, you push the end cap onto the pipe and then slice the common area to make a ring set. I made a set approximately 1/4 inch in thickness. You then place the inner ring on a flat surface, turn the bag inside out and position it over the inner ring, and then squeeze down the outer ring to clamp the bag in between the two rings. You then carefully cut the nylon bag out to make room for the filter and press fit the filter into the inner ring opening. Walla, you're done!

    Some other hints on this method. While the outer ring slips over the inner ring very snugly by itself, it will be really snug with the nylon bag material and the filter inserted. So I first rough sanded the inside and outside diameter of the pipe to help this fit a little. If you can, plan on never taking the rings apart after you cut the bag material. It becomes difficult to line up the material the same way once they are separated. Also I used a miter saw to make rings with uniform, clean edges, although I don't see why it wouldn't work if you hand sawed the rings. To keep it safe, make sure you are cutting through both the end cap and the pipe on each cut and have enough length of end pipe to steady the assembly while cutting.

    Once the bag is clamped, its a snug fit to insert the filter, which is actually a good thing. If you remove the O ring, you should be able to insert the filter all the way up to the threads and make a very tight seal that won't easily come loose. Finally, I loosely placed the filter in the hole, and then rested the assembly in the open jaws of a bench vise so that I could 'knock' the filter down using a wooden block and some gentle taps.

    The whole assembly weighs 7 oz dry (9 oz damp) and filters 2 liters in 7 minutes. Here are some photos of the finished assembly. Note I slipped the O ring back on after assembly just for the sake of storing it on the filter in case I ever need the original back.Inside Out ViewOutside View

    #1615210
    Jay Wilkerson
    BPL Member

    @creachen

    Locale: East Bay

    This system is Easy too and much lighter!
    P1010226

    Brass screen filter ways 0.5oz and is used before liquid Aquamira.

    P1010219

    #1615284
    Michael Davis
    Member

    @mad777

    Locale: South Florida

    Good looking design and nice weight, too!

    The only potential problem I have found with gravity filters that have the filter in the collection bag, is lack of pressure for some filter cartridges.

    The cartridges that have a slow flow rate, need the filter near the bottom of the tube to take advantage of the pressure from the long column of water.

    But, then again, one of the nice things about a gravity filter is that you get to stop and smell the roses, while the filter is working :-)

    #1616368
    tim hower
    Spectator

    @jeepcachr

    Locale: Great Lakes

    [q] The only potential problem I have found with gravity filters that have the filter in the collection bag, is lack of pressure for some filter cartridges. [/q]

    I've been using the Katadyn hiker base camp gravity filter for a few years and have never had an issue with it needing pressure.

    It looks like it's time for me to lighten up though and convert it to use one of these walmart bags. I've got the walmart bag and the 2" pvc, just need an end cap and I'm good to go.

    Edit: My Base camp filter came with a plug for the filter so I take the hose off and plug in when dipping it in the water to fill it. I never worry about cross contamination that way. I then take it back to camp and hook up the hose.

    #1616578
    Josh Platt
    BPL Member

    @easternbox

    Locale: Southeast

    I have made a filter just like the first one shown in this thread and I too have never had an issue with lack of pressure. The Katadyn filters work wonders for me.

    #1616584
    Michael Davis
    Member

    @mad777

    Locale: South Florida

    I didn't mean to imply that this isn't a great setup. The Katadin and many other filters will function swell in this mode.

    I was just trying to make the point that the filter should match the setup. I've used Sawyer's virus filter and it needs all the help it can get from gravity due to it's tiny pore size, which nearly filters out water molecules :-)

    #1616763
    Keith Selbo
    Spectator

    @herman666

    Locale: Northern Virginia

    As far as I'm concerned, gravity filters are the only way to go. I've pumped and I've Steripened and I've waited 4 hours for chemicals to kill giardia. Nothing beats hanging a bag, finding some other task to do and coming back to purified water.

    That said, I don't believe in doing half a job. Just filtering will leave viruses in the water. Chlorine will kill the viruses almost instantly, but it leaves a bad taste. What to do? I follow my Sawyer bacterial filter with a Katadyn charcoal filter. The activated charcoal removes the chlorine I added to kill viruses leaving great tasting purified water. The filter setup is pictured below. One end screws onto a platypus bag holding the dirty water. The other snaps into my Nalgene hydration bladder. The right angle under the charcoal filter is a valve. Total weight including platypus bag is 9.2 oz.
    sawyer and katadyn combination

    #1618524
    S Long
    BPL Member

    @izeloz

    Locale: Wasatch

    This thread inspired me to try my hand at making something like this. I used silnylon cut into a 32" diameter circle. I used the cap off a 16 ounce cheapo water bottle and a 1/4"X1/8" nylon hose fitting. I used silicone to seal the inside. It's not done yet but I plan to finish it tomorrow. Would have preferred cuben but I figured I would use what I had on hand for now. I plan to use an inline filter with 1/4" hose barbs with this water bag.water bag 1water bag 2water bag 3

    #1618593
    tim hower
    Spectator

    @jeepcachr

    Locale: Great Lakes

    I already had a katadyn base camp, a old nalgene, and the walmart water proof bag. I converted to the walmart bag and saved 4 onces plus it packs smaller. I only gave up a small amount of water capacity by going to the smaller bag but its still larger than what I will typically need. I thought about using the medium or small bag walmart bag but it wasn't worth the fraction of an once to go smaller.

    I am not a gram weenie. I consider myself a lightweight guy not an ultralight. I'm very happy with this mod.

    #1618659
    obx hiker
    BPL Member

    @obxer

    If this basic set-up has been posted before my apologies.

    Thanks and all credit to hammock forums Angry Sparrow: a truly creative outdoorsman.

    http://www.hammockforums.net/forum/showpost.php?p=174954&postcount=19

    The filter shown weighs 5 oz with the zing-it hanger( filter/bag/fittings/hanger only…. no tubing, no 2 liter platypus…….. plus a wet filter weighs more for quite some time ) and can be used as a hydration system with no extra bag(drink through the filter) It could probably likely be cut to 4oz by trimming the non-filtration parts off the micro-filter and using one of Lawson/mountainfitter cuben dry bags.

    The bag shown is a 4 liter Sea to Summit from REI

    amgp 1s

    amgp 2s

    amgp s3

    amgp s4

    amgp s5

    amgps

    amgps7

    Apologies for the sideways shots. Fill it, hang it and forget it.

    PPS: Tony; the link above has the fittings source and part #'s and them appear to be those. haha

    Joe: nice job on trimming the filter! using your weight for a trimmed filter yeilds a weight for this set-up of 3.4 oz. The dry bag closure has a rigid strip around the bag rim @ 1" wide and buckles which undoubtedly "wastes" at least the .4 and likely more.

    I've been encouraging Lawson at Mountainfitter to design a cuben bag for just this purpose. Come-on Lawson! A 200 gallon 3 oz smooth flowing…. not so inclined to plug-up ( hint hint frontier-pro), micro-filter gravity system/ hydration system.

    #1618676
    Kevin Beeden
    BPL Member

    @captain_paranoia

    Locale: UK

    Lightweight filters do seem to have come a long way. I use one from DrinkSafe Systems.

    They have ready-made gravity bag systems, too.

    I know; this sounds like a commercial plug, but I have no connection with them other than as a customer.

    ps. I know it's not MYOG, but it's a bit hard to MYOG viral filters…

    #1618753
    Mary D
    BPL Member

    @hikinggranny

    Locale: Gateway to Columbia River Gorge

    Thanks, Cola, for the great pictures and the link to hammockforums for the supplies! I need to order tubing and will be making my own as soon as it arrives!

    #1619182
    obx hiker
    BPL Member

    @obxer

    You're welcome Mary! I'd suggest you order about 3 or 4 of each part since the shipping ends up being one of the biggest expenses.

    BTW The plastic end caps for closet maid shelving work great as a plug for the outlet fitting. Allows you to fill the bag, carry it around etc without the hose attached
    (and held up high to keep it from draining!)

    Ordered a Cuben Fiber CTF3 Rolltop Drybags @ $15.95
    size: 8"x12 from mountainfitter.Quoted as 4 liters. Wish I had a bandsaw like Joe. Guess I'll carefully try the table saw. 3oz or bust!

    #1619229
    tim hower
    Spectator

    @jeepcachr

    Locale: Great Lakes

    the table saw doesn't seem like a good idea. it would only take a minute to do with a hand saw or hack saw.

    #1619404
    obx hiker
    BPL Member

    @obxer

    Tim problem is the depth of the cut needs to be just right, and those microfilter casings are made of tough plastic.

    I don't know I guess I'm afraid I might slip doing it by hand.

    The first time i read a report about trimming off the excess on hammock forums the guy used a dremel. That's a hand tool but a fast blade is also easier to control. I guess a lttle reticence about which way to proceed is why I haven't trimmed the thing yet.

    Any good ideas about trimming the casing on a microfilter out there?

    #1620456
    obx hiker
    BPL Member

    @obxer

    I just received the 4 liter dry-bag from Mountainfitter. The black bag! Appears very well made and wicked light at .5 ounce. Just about a perfect size and shape for a filter/hydration bag.

    if I can trim the micro-filter to Bill F's weight of 1.9 oz that would yield a sub 3 oz gravity filter with a 200 gallon life that is easily modified on the fly for hydration and is minally prone to clogging. Dry-Bags with a semi-rigid rim are really easy to fill as well.

    I'll up-date when I get to it. ( don't hold your breath! )

    #1898059
    Brian Johns
    BPL Member

    @bcutlerj

    Locale: NorCal

    Thanks to Mary to pointing me to this thread. I just went to REI and grabbed the "Platypus Gravity Works" replacement filter. It's an uberlight little cartridge that, I believe, is intended to go inside the gray, bulky filter portion of the dual platy system. I also bought a platypus connector and hose.

    My question is this, can I replace the in-line, seychelles filter on my ULA with this little guy and expect it to work as well as what is currently there? If so, I think I can deal with the "weight" of the silnylon and will have a perfect system so long as platy hoses mate with my ula bag/fittings.

    Here's a pic:Gravity Works Replacement Filter Element Light and tiny

    #1898060
    Backpack Jack
    BPL Member

    @jumpbackjack

    Locale: Armpit of California

    I believe that filter only takes out the bad taste, you might check to see if it filters out the bad stuff like Giardia.

    #1898066
    David Thomas
    BPL Member

    @davidinkenai

    Locale: North Woods. Far North.

    From REI's website:

    "•Removes flavors, odors and many organic compounds from filtered water to improve the taste
    •The Platypus GravityWorks Carbon element should be used to improve the taste of safe water sources only; element does not remove viruses, bacteria or protozoa from water"

    This is a routine aspect of my day job (cleaning up toxic waste sites) and a carbon filter WILL remove gasoline, benzene, chlorine, and many pesticides.

    It WILL NOT remove pathological organisms and the "plate counts" of bacteria will typical go UP after a carbon filter because of the tremendous surface area they give the biofilm to live on and because it dechlorinates the water passing through it.

    It will improve the flavor and decolorize many waters. It may make it chemically safer. It will not protect you against biological issues. Pity, because it is small and compact!

    #1898085
    Brian Johns
    BPL Member

    @bcutlerj

    Locale: NorCal

    It weighs so little I may just add it in line with the Seychelles for added/pre-filtration.

    #1898088
    Backpack Jack
    BPL Member

    @jumpbackjack

    Locale: Armpit of California

    This is what I use now. Maybe David could chime in on this one.

    Jack

    #1898093
    Randy Martin
    BPL Member

    @randalmartin

    Locale: Colorado

    David, you said "This is a routine aspect of my day job (cleaning up toxic waste sites) and a carbon filter WILL remove gasoline, benzene, chlorine, and many pesticides."

    Does Carbon remove any metal/mineral contamination from mine runoff?

    I have always heard that nothing will remove mine runoff contamination which is actually one of the primary issues in many Colorado and locations in the Western US in general.

    #1898108
    David Thomas
    BPL Member

    @davidinkenai

    Locale: North Woods. Far North.

    The CR-100 claims effectiveness against micro-organisms although their website leaves me unclear whether it is the sintered carbon or some separate filter that blocks the passage of small particulars. The company is well known, the claims reasonable, and I would be fine relying on it for taste and biological treatment.

    #1898118
    Brian Johns
    BPL Member

    @bcutlerj

    Locale: NorCal

    Combined with aqua Mira in more queationable areas, this may do the trick. A+ discovery wasabi for was that Platypus hosing fit the ULA reservoir.

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