In the constant struggle to reduce my pack weight I have been looking at gravity filter, specifically the ULA Amigo water filter.

I know that the Amigo uses the filter from a Pur/Katadin Hike water filter which I already have and use. I was wanting to make the gravity filter using the filter out of my Pur Hiker. The water bag portion of the gravity filter would be pretty easy to make and I already have the material to do so.

I was mainly worried about the middle section of the gravity filter, the section where the filter attaches on the inside of the bag that leads to the output hose on the extreior of the bag.

Is there something that I can buy and use in this section or would it just be better for me to buy an Amigo minus the actual filter?

Has anyone ever made their own gravity filter? Are there plans available?

There are plans in Ray Jardine's book Beyond Backpacking for a water bag / gravity filter system made with a 30" silnylon circle with 8 equally spaced tabs around the side, 6 - 8' of clear tubing, some cord to suspend the bag and a filter cartridge that will fit the tubing. Basically, it is a simple water sack with a way to hold the filter down in the water. You start the system by sucking on the free end of the tubing.

A second method in Jardine's book gives a way to cut a hole in the center of the bag and fit it with a filter cartridge. When using this method it is also important to let the tubing going into you water bottle dip down below the edge of the water bottle so that any dips leaking down the outside fall on the ground instead of running into your filtered water.

Check out this thread over on BackpackingLight.com. Photos show just how to do it. I made one, It works great.

http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/8994/index.html?skip_to_post=65095#65095

Check out this thread over on BackpackingLight.com. Photos show just how to do it. I made one, It works great.

http://www.backpackinglight.com/cgi-bin/backpackinglight/xdpy/forum_thread/8994/index.html?skip_to_post=65095#65095


Thanks for the link.

I also gave a copy of Beyond Backpacking that I will use as reference.

Just finished making gravity filter. Used roll top stuff sack from walmart and the swayer water bottle with filter also from walmart. I used a 16oz small mouth nalagene bottle I had laying around to connect too the roll top bag as described in the backpacking light forum. I then drilled a hole in the top of the nalagene lid and used the male connector that came with the swayer water bottle and insert through the hole i drilled. I then sealed it, i used the two part putty you mix together in your hand, it hardened in ten minutes. I used tubing from home depot to put the swayer filter in-line. It is light and works well. Can't wait to try it in the woods Thanks for the idea.

Check out the BPL thread. It is a great design. For the bag, you can make it similar to Ejacobsons. Use a wide mouth nalgene neck, cut just below the threads. Cut a hole in the nalgene top about the diameter of the filter element. You then put the neck inside the bag where you want the output and screw the top on the neck with the bag in between. After they are tightened, cut a hole out of the bag where the hole in the top is. This will give you a place to insert you filter, very similar to the amigo set up. I have made one using the PUR filter and an inline using the sawyer. I prefer the sawyer set up. Get some cuben and make a superlightweight bag. Good Luck.

First Need used to offer a gravity feed adaptor for their filter. I used it once (bag is really too small to make it useful). It came with a nipple that you'd stick through a plastic bag, put the bag inside the filter storage sack, attach tubing to bag and filter, and filter into water bottle. It worked well, but took a long time.

Where is the Sawyer filter located in WalMart? In the camping section? Cost?

the filter is located in the camping section. It comes in a kit with the water bottle. The rolltop stuff sacks are also in the camping section, they come in a pack of three. I used the biggest one (green). I also picked up a light inflatable pillow in the camping section. I am a side sleeper and stil struggle with a way to sleep on my side comfortably. I have broad shoulders so i need a pretty high pillow to feel comfortable.

i already use the 3 pack of WalMart dry bags and I made a DIY gravity filter from the filter cartridge from my PUR Hiker and one of the WM bags. I just keep hear about this Sawyer water filter. I may try one of those.

Just finished making gravity filter. Used roll top stuff sack from walmart and the swayer water bottle with filter also from walmart. I used a 16oz small mouth nalagene bottle I had laying around to connect too the roll top bag as described in the backpacking light forum. I then drilled a hole in the top of the nalagene lid and used the male connector that came with the swayer water bottle and insert through the hole i drilled. I then sealed it, i used the two part putty you mix together in your hand, it hardened in ten minutes. I used tubing from home depot to put the swayer filter in-line. It is light and works well. Can't wait to try it in the woods Thanks for the idea.

Big J helped me build one of these... Heck of a lot lighter than my 10+ year old PUR pump filter, water tastes better, and NO PUMPING!!!

If youwant to make this without using any type of putty or bonding agent, after inserting the adapter piece, cut a very small ( 3/8 ") length of tubing and push it on the inside part. If the hole you make is smal and the fit of the adapter is tight, it will not leak this way. I made mine using 2 liter bottle necks and caps. Works great and absolutely ) leaks. I will post pics tonite.

Pictures of my Sawyer SP 120 (https://sawyergear.com/products.asp) setup in use at Low Gap Shelter last week. Clean bladder can be left in pack (loosen straps to allow for expansion) and bite valve can be removed with quick connect. Clean side of connection is protected from cross contamination during storage with Platypus bite valve cover. Quick connect filter between each bladder, squeeze full bladder to get things moving and sit back. 2L takes about 3 minutes (quicker if you continue to apply pressure). Dirty bladder easily identified by hanging strap. I found a small funnel made by Zep at Home Depot and the threads are a match to the bladder. It helps when filling the bladder. Filter as shown is 4oz. including 2.4L Platypus bladder with strap. :cool:

Pictures of my Sawyer SP 120 (https://sawyergear.com/products.asp) setup in use at Low Gap Shelter last week. Clean bladder can be left in pack (loosen straps to allow for expansion) and bite valve can be removed with quick connect. Clean side of connection is protected from cross contamination during storage with Platypus bite valve cover. Quick connect filter between each bladder, squeeze full bladder to get things moving and sit back. 2L takes about 3 minutes (quicker if you continue to apply pressure). Dirty bladder easily identified by hanging strap. I found a small funnel made by Zep at Home Depot and the threads are a match to the bladder. It helps when filling the bladder. Filter as shown is 4oz. including 2.4L Platypus bladder with strap. :cool:

Oops! Here's the pictures.

Pictures of my Sawyer SP 120 (https://sawyergear.com/products.asp) setup in use at Low Gap Shelter last week. Clean bladder can be left in pack (loosen straps to allow for expansion) and bite valve can be removed with quick connect. Clean side of connection is protected from cross contamination during storage with Platypus bite valve cover. Quick connect filter between each bladder, squeeze full bladder to get things moving and sit back. 2L takes about 3 minutes (quicker if you continue to apply pressure). Dirty bladder easily identified by hanging strap. I found a small funnel made by Zep at Home Depot and the threads are a match to the bladder. It helps when filling the bladder. Filter as shown is 4oz. including 2.4L Platypus bladder with strap. :cool:

That is slick, way cool. You are really only adding the weight of that small filter 'cause you are carrying the platys anyway. A Polar Pure bottle will weigh nearly what that filter weighs.

That is slick, way cool. You are really only adding the weight of that small filter 'cause you are carrying the platys anyway. A Polar Pure bottle will weigh nearly what that filter weighs.

Exactly! the Platypus used for the dirty water is 2L now that I've compressed the base by adding the strap and the grommets. I've measured 1L into this and marked it with a Sharpie since I normally only carry that much. Either way, the 1L & 2L measurements allow me to know exactly what I have and drop 1 or 2 Micropur tablets into the clean water for virus protection. Frankly, if I were not filtering water for both myself and my buddy I'd just mount this in-line between my bladder and my mouthpiece. I may do that anyhow, he can carry his MSR Sweetwater! :cool:

gear what was your cost for this total project? i'm about to embark on building my own filter and would like to use yours as a template

The filter cost me $19 thru the site I've provided the link to earlier in the thread. A 2.4L Platypus is $10, a Platypus drink tube is $13, bite valve cover is $6. All Platypus items are here (http://www.rei.com/search?query=platypus). I lay my bladder at the top of my pack with the opening to my left. I've put the filter inline so it lays across the bladder and the drink tube exits the right side. I now filter as I drink. If you want to hang this as in the picture and filter into other containers you can punch holes in the reinforced foot on the bottom of the bladder and attach some para cord. It helps to have a quick connect (http://www.rei.com/product/695526) in this setup, otherwise you'll be pinching the bite valve to fill your cook pot (which isn't all bad)! So, you can do this for as little as $42 with a weight of approximately 6 oz. :cool:

The filter cost me $19 thru the site I've provided
the link to earlier in the thread.
The SP-120 filter must be discontinued, I don't see it on Sawyer's site you linked. The cheapest filter listed is the SP-121 for $60.00 :eek: :(

The SP-120 filter must be discontinued, I don't see it on Sawyer's site you linked. The cheapest filter listed is the SP-121 for $60.00 :eek: :(

You could try this one (http://www.seychelle.com/ProductDetail.asp?ProductID=36058&RepID=10001&CategoryID=386&BasketID=). Its a little cheaper, but I don't know how it stacks up.

Sawyer has come out with some new products designed like the ULA Amigo and Platypus CleanStream (should it ever make it to market). I guess I was in the right place at the right time to get this so cheap. :cool:

You can get the Sawyer sp120 for 36.65 and the sp121 for 39.75 from moontrail. The link to the sp120 is http://www.moontrail.com/sawyer-sp120-inline-water-filter.php and the link to the sp121 is http://www.moontrail.com/sawyer-sp121.php

I went with the sp121 mainly because the filter life 1 million gallons for the sp121 vs 500 gallons for the sp120. In addition, the sp121 comes with the faucet adaptor to easily backwash the filter and the sp120 doesn't and the sp121 was only 3 dollars more. That is the cheapest place I could find it.

Gearfreak....You referred to a "quick connect" that you use to connect the bladders together when transferring water from the dirty bladder to the clean bladder. Can you explain exactly what that is because I couldn't tell by looking at the picture. I am looking to complete this system to carry going forward. Thanks.

Gearfreak....You referred to a "quick connect" that you use to connect the bladders together when transferring water from the dirty bladder to the clean bladder. Can you explain exactly what that is because I couldn't tell by looking at the picture. I am looking to complete this system to carry going forward. Thanks.

Maybe this will help:

http://www.platypushydration.com/product_detail.aspx?ProdID=33&CategoryID=5

Maybe this will help:

http://www.platypushydration.com/product_detail.aspx?ProdID=33&CategoryID=5
thanks, take-a-knee.
they have a nice shut-off valve i can use for my DIY wall-mart gravity bag:)

thanks, take-a-knee.
they have a nice shut-off valve i can use for my DIY wall-mart gravity bag:)

The shut off (and tubing) from a camelback will work also, the tubing also works with those fittings that Platypus sells.

Thanks, take-a-knee...That is exactly what I needed to see. That explains alot. I work better with pictures:)