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Brett .
(Brett1234) - F

Locale: CA
re:"ultralight water prefilter"/paper cone coffee filters on 05/18/2008 20:08:51 MDT Print View

Another vote for coffee filters. I carry the cone-shaped type for pre-filtering before I add a micropur tablet. Works for any container, disposable or reusable, biodegradable, and maybe 1 gram each.
My pocket survival kit has a tiny ziplock with one filter and one micropur.

Edited by Brett1234 on 05/18/2008 20:10:29 MDT.

Brian Barnes
(brianjbarnes)

Locale: Midwest
RE:"ultralight water prefilter" on 05/18/2008 21:03:31 MDT Print View

So am I understanding what you folks are doing with a filter correctly: 1) you acquire the water from its source (stream, etc), 2) transfer the contents of the first container through a filter to a second container, 3) treat "filtered" water with UV or chemicals. Am I on track here?

Ben 2 World
(ben2world) - MLife

Locale: So Cal
Re: RE:"ultralight water prefilter" on 05/18/2008 22:04:27 MDT Print View

Yes. A "water scoop" of sorts is needed esp. for narrow mouth, collapsible bladders.

Water that's pre-filtered can be more aesthetically pleasing (or at least less disgusting) -- and it also allows both UV and chemicals to do their job more effectively.

Edited by ben2world on 05/18/2008 22:08:08 MDT.

Frank Deland
(rambler) - M

Locale: On the AT in VA
filter after using a steri-pen on 05/19/2008 15:02:16 MDT Print View

Hennessy Hammocks makes a funnel that is attached to a screw on top that fits on a platypus bottle. Take a small piece of no see-um netting and attach it with tape or an elastic band to the top of the funnel. It strains out the floaties. (Hennessy uses the funnel to deflect rain water off the hammock support ropes into a bottle.) scroll down at this link
http://hennessyhammock.com/new-products.html

Edited by rambler on 05/19/2008 15:05:41 MDT.

Matthew Swierkowski
(Berserker) - F

Locale: Southeast
Re: Re: ultralight water prefilter on 03/03/2011 06:52:41 MST Print View

Alright, I hate to sound totally dense here, but I looked at John (Quoddy) and Ben's pictures for how they made the cap with the mesh screen in it and I just don't get it. I bought a coffee filter (Mr. Coffee) that has gold colored metal mesh screen, cut a round piece out, drilled/trimmed a hole in a platy cap, and then tried to get the screen to press fit down into the cap. The problem is that the cap I am using has an extra smaller diamter raised piece in it that goes on the inside of the bottle opening, which is totally different than most bottle caps that just have a flat surface with a rubber gasket. So am I missing something obvious here, or are the caps that were used in this thread different?

KEN LARSON
(KENLARSON) - MLife

Locale: Western Michigan
Ultralight Water Prefilter on 03/03/2011 08:09:45 MST Print View

Information that might aid in the making of the pre filter discussed above.

Modified Gator Aid Cap and Nalgene Cap showing the mesh epxoxied within. You must leave a lip of the original plastic around the inside of the cap for the mesh to rest on and for the epoxy to adhere to.

Nalgene Cap

Nalgene Cap

Gator Aid Cap

Gator Aid Cap

Krups Filter

Gold Tone Coffee Filter mesh size is 3 microns (Source: Krups Consumer Service)

Edited by KENLARSON on 03/03/2011 08:16:34 MST.

Matthew Swierkowski
(Berserker) - F

Locale: Southeast
Re: Ultralight Water Prefilter on 03/03/2011 08:27:21 MST Print View

@Ken

Ahhhh...so it's glued in there. I got the impression that it was somehow just press fit in there. Ok, I actually left a lip on the cap I was working with so gluing in a piece of screen would be no big deal. Now the million dollar question...what glue to use? You mention epoxy, does that work and what epoxy did you use?

I was working on a much more complicated pre-filter than the one in this thread when I came on this thread, and per my research there are not many adhesives that stick to polyethylene or polypropylene (the materials most of these bottles and caps are made of). The only thing I found that works is the Loctite Plastic Bonding System (consists of an activator and super glue). I suppose another potential option would be to melt the screen into the plastic with a soldering iron. Anyone tried that?

Brendan Swihart
(brendans) - F - MLife

Locale: Fruita CO
metal screens for turbid water? on 03/03/2011 08:43:28 MST Print View

are the metal screens you guys are using fine enough to prefilter silty/turbid water for use with a steripen? For convenience sake or if you're just trying to get out floaties the fine mesh seems great but if you're trying dealing with more murky water it seems like paper filters would be better??? I have an opti on the way and some places I frequent the water can have lots of clay so I'm wondering what a good setup will be.

jerry adams
(retiredjerry) - MLife

Locale: Oregon and Washington
Re: metal screens for turbid water? on 03/03/2011 08:53:26 MST Print View

Those filters are for sticks and leaves and things

No filter is good for silt

Even pump or gravity filters aren't that great for silt - they'll plug up for one thing

I fill my 4 liter Platypus, and then the next morning most of the silt is on the bottom, just don't agitate the bottle and pour off the top.

To treat turbid water, the instructions say to double treat

Katharina ....
(Kat_P) - MLife

Locale: Pacific Coast
Cheese cloth on 03/03/2011 09:00:20 MST Print View

A 4" x4" piece of cheese cloth, folded twice, to make four layers. Works much better
(faster) than a bandanna and seems to catch a certain amount of silt too.

KEN LARSON
(KENLARSON) - MLife

Locale: Western Michigan
Insight to pre filtering on 03/03/2011 11:35:53 MST Print View

Matt……“You mention epoxy, does that work and what epoxy did you use?”

>>>>>GORILLA. The Glue Guide by Gorilla does state, “Bonds most plastics, but not polyethylene or polypropylene as you had mentioned.” I have had no issues to date with the caps and as long as the adhesive holds the screen in place without fall out (my purpose) the cap pressure will do the rest.

Brenda…..“are the metal screens you guys are using fine enough to prefilter slit/turbid water for use with a steripen."

>>>>>I use my prefilters with my SteriPen when needed and that has not been that often as I am VERY SELECTIVE when it comes to the amount of dissolved and suspended solids in the water source I take my water from due to my suppressed immune system. When I use my Larson Designed Gravity System (Sea To Summit 8 liter Ultra-Sil Dry Sack, 5 micron (nominal) pre filter sewn into the bag, Sawyer .02 purifier) with my grandchildren I have also no issues and produce water in large amounts (Average 290 sec/liter) quickly when I suspend 1.5 gal at a time.
Prior to using a pre filter with the Larson Designed Gravity System, I had one big issue in it early testing with Lake Michigan Water in early Spring around South Manitou Island using water that had large amounts of suspended Cladophora algae that you could observe (a native algae species that washes up on the beaches when wind-driven waves rip it off the bottom of the lake and becoming a big issue for the ecology of the lake.) in the water. With my updating of the system I have had great success with many different water sources and “suspended solids” contained within.

Jerry…… “Even pump or gravity filters aren't that great for silt - they'll plug up for one thing”

>>>>> I had a silt issue at Lake Desor (North) on Isle Royale back when I was using a Katadyn Pocket filter (HEAVY, 0.2 micron ceramic filter (cleanable) without pre filtering the water on year, but I quickly corrected this by scrubbing the ceramic filter. (The suspended solids were so fine you could not discern with the naked eye. This island also had Cyanobacteria (Blue green algae) issues in the late summer and closes several inland lakes to the potential health risk to people who are exposed to certain species that contain a toxin. In this case if you see “blooms” or “scum’s on the water you are drawing from…..be conservative and do not use the water. People with other filtering device that used these waters were not so lucky, as thier filters clogged and could not be cleaned.)

Katharina…. “A 4" x4" piece of cheese cloth, folded twice, to make four layers. Works much better
(faster) than a bandanna and seems to catch a certain amount of silt too.”

>>>>This information may interest you:

Back in the lab I tested “grubby bayou” (Late Summer water in front of my house that is a good sampling source for these test.) water through various pre filter materials to determine what material makes the best pre filter. This is what I found out:
1. paper coffee filter - water very clear (as tap), filter rate very slow
2. cloth coffee filter - water tinge of yellow, filter rate slow
3. pelon material - water slight tinge of yellow, filter rate very fast
4. handkerchief - water tinge of yellow, filter rate slow
5. heavily used MSR towel (PackTowl® Ultralite) - water clear, filter rate fast
6. lightly used MSR towel (PackTowl® Ultralite) - water clear, filter rate medium
7. MSR towel (Nano™ Towel) - water clear, filter rate medium fast

CONCLUSION: The use of either the MSR towel (PackTowl® Ultralite or MSR towel (Nano™ Towel) would be the best pre filter material prior to UV, filtering, or purifying water with suspended solids (e.g. algae, bugs and floating debris.) Each of MSR pre filter materials can be washed in the field and used again and had has sufficient surface area to handle most filtering/purifying pre filtering needs. The use of a strong rubber band would aid in affixing the pre filtering material in place around a pot or liter btl/canteen so to enlarge the filter area.

NOTE: The QUALITATIVE nature of the water clarity is based on sight comparison to tap water or water that has been place through a paper coffee filter.

Edited by KENLARSON on 03/03/2011 13:35:44 MST.

Roleigh Martin
(marti124) - MLife

Locale: Moderator-JohnMuirTrail Yahoo Group
Best pre-filter is a 1 oz, 1 micron oil filter from DudaDiesel on 03/03/2011 12:31:13 MST Print View

http://www.dudadiesel.com/choose_item.php?id=PESP3S

About $3

I've used this for 2-3 years now. Fantastic. Take a wire clipper and clip cut the steel ring, and use a needle nose to remove it, and the remaining filter folds flat and is 1 oz. It is a one micron filter too!1 Micron Oil Filter

Link .
(annapurna) - MLife
Re: Best pre-filter is a 1 oz, 1 micron oil filter from DudaDiesel on 03/03/2011 12:38:04 MST Print View

+1 Roleigh, I purchased from Dudadiesel a couple of years ago after reading your post and have been very happy with it.

Brendan Swihart
(brendans) - F - MLife

Locale: Fruita CO
prefilter on 03/03/2011 12:48:58 MST Print View

good info Ken and Roleigh. How is the flow rate through those diesel filters? Looking around a bit it looks like a paper coffee filter is between 15 and 30 microns for reference so 1 micron would be pretty awesome if it allowed water through relatively fast.

KEN LARSON
(KENLARSON) - MLife

Locale: Western Michigan
Re: Best pre-filter is a 1 oz, 1 micron oil filter from DudaDiesel on 03/03/2011 12:49:35 MST Print View

I have incorportated this filter material in my gravity system describe above. (You can go as low as 1 micron (nominal).

Global Filter, LLC

Standard Mesh Liquid Filter Bags. I believe the specifications of a bag and material I'm looking at are as follows:

Type Fiber - NMO
Micron Rating - 5
Bag Finish - Plain
Bag Size - 1
Bag Style - PESS

http://www.globalfiltercorp.com/StandardMeshLiquidBags.html

Terry Younggreen
Vice President of Operations

7201 Mt. Vernon Rd SE
Cedar Rapids, IA 52403

toll free: 1-877-603-1003
ph: 319-743-0110
fx: 319-743-0220

Email: terry@globalfiltercorp.com

Edited by KENLARSON on 03/03/2011 13:33:34 MST.

Rick Dreher
(halfturbo) - MLife

Locale: Northernish California
Re: Insight to pre filtering on 03/03/2011 12:53:48 MST Print View

Hi Ken,

Wonderful roundup of filteration fabrics. I confess I had to look up "pelon" and the closest I can find is "pellon" facing as used in sewing. Is that the stuff?

So you suppose the pack towel fabric works so well because it's highly hydrophilic?

Thanks again,

Rick

KEN LARSON
(KENLARSON) - MLife

Locale: Western Michigan
prefilter on 03/03/2011 12:59:32 MST Print View

Brendan.........The 5 micron bag I described used with my gravity filter works as good as any pre filter I have tested. NO ISSUES.

"Looking around a bit it looks like a paper coffee filter is between 15 and 30 microns for reference so 1 micron would be pretty awesome if it allowed water through relatively fast."

>>>>>That is a correct statement for the 5 micron and I bet it is likewise for the 1 micron.

Roleigh Martin
(marti124) - MLife

Locale: Moderator-JohnMuirTrail Yahoo Group
Re: Best pre-filter is a 1 oz, 1 micron oil filter from DudaDiesel on 03/03/2011 13:00:33 MST Print View

Thanks Anna. Glad this thread came up. I thought prior to today that using a 1 micron pre-filter along with Chlorine Dioxide tablets (but only waiting 20" after use of tabs), that filtering mountain water would be just fine to use as the items you needed to wait 2-4 hours for with the tablets had sizes greater than 1 micron. But then I saw this today: http://www.usbr.gov/pmts/water/media/pdfs/Crypto.pdf

"B. Source in Nature: Crypto and giardia are naturally occurring in the intestines of most mammals, including humans. The highly contagious and infectious form, as found in water, is a hard-shelled cyst in the case of giardia, about 5-8 microns in diameter; and an oocyst for crypto, about 3-5 microns (which is pliable and capable of folding to 1 micron)."

I did not know giardia could be as small as 1 micron.

I've used the pre-filter in 3 situations:

a. pre-filter for steripen to rid water of any crud (by the way, steripen's own technical literature says it does not purify a wolf parasite eggs which are too big for the steripen to handle, but the pre-filter will take care of that).

b. pre-filter for chlorine dioxide tablets (on my JMT hikes, I use the Steripen during the day as the water tastes better that way, but at night, I'm so tired, and water is mostly for cooking, and I use the chlorine dioxide tablets, and wait only about 30" afterwards). In both situations, I use the 1 micron pre-filter.

c. as a pre-filter for a .1 micron sawyer gravity water filter on the superior hiking trail which afterwards I then use chlorine dioxide tablets (to handle viruses).
The pre-filter helps enable me to go more days before the sawyer gravity filter gets too plugged up and needs backflushing.

Roleigh Martin
(marti124) - MLife

Locale: Moderator-JohnMuirTrail Yahoo Group
Re: prefilter on 03/03/2011 13:02:29 MST Print View

Brendan, the flow rate is so fast, it's like a filter is not involved. It's only 1 micron, not something really, really small like .1 micron. I think it is also fast because it is such a large filter and can handle a lot of volume.

Roleigh Martin
(marti124) - MLife

Locale: Moderator-JohnMuirTrail Yahoo Group
Re: Re: Best pre-filter is a 1 oz, 1 micron oil filter from DudaDiesel on 03/03/2011 13:08:54 MST Print View

Ken, what is the part number of your 1 micron (absolute) filter equivalent to the one I showed from Dudadiesel. What do you mean by "absolute". You'll note the wording by DudaDiesel:

"This fabric does not produce an absolute filtration but rather a range based on generally accepted industry tests. Mandy factors influence the actual filtration including the shape, size, consistancy and loading of the contaminates. Also, the feed pressure and rate of flow affects the filtration results. "

http://www.dudadiesel.com/choose_item.php?id=PESP3S

Last, what is the pricing information and minimum qty order you'll take?

The Dudadiesel bag has these characteristics:
Polyester Filter Bag
• Size#3, with hanging strap
• 8" Length, 4" Diameter
• Singed for prevention of fiber breaking
1 micron (with above caveats)