Sawyer Squeeze Filter Modifications Part 2 – Cleaning Syringes and Storage Bag

Posted: September 12th, 2012 by: h2

The Sawyer Point One Squeeze filter (0.1 micron version) has grown to be one of my favorite pieces of gear.

There are two pages of modifications:

Ok, so you’ve done Part 1. This now lets you do part 2, and fixes what is in my opinion the single weakest part of the Sawyer Squeeze design, the backflushing syringe they include. First, the one they provide is really big. Second, it doesn’t seat nicely into the clean end of Sawyer Squeeze, you have to sort of press it on.

However, have no fear, that’s an easy problem to solve.

Changing Irrigation Syringes – On Trail And Home Use

[Update: do not follow this suggestion, I have reconsidered this question and this is a bad idea, use either 60ml syringe for maximum 2oz flow for about 1 second, or use nothing. Use of smaller syringes can lead to filter tube channeling, which is not reparable). The long tip 60ml however works very well, and is highly recommended.

I had a brain storm (too bad it was wrong, see note above), and realized I should check for smaller or better fitting irrigation syringes. That’s what that big thing is, with the plunger. After discovering that big pharmacy chains were totally useless and didn’t carry such things, I went to an old local store, Johnson’s Medical Supply in Berkeley, if you live in a larger city, you almost certainly have a true medical supply store. NOT, repeat, a junk filled big box chain place, it’s a store dedicated to only medical supply products.

So I went, and, lo and behold, I found two syringes, one absolutely perfect for home cleaning, or bounce box storage and in town resupply type use, the other a bit too small, but I think it will be sufficient for on trail cleaning. And boy is the small one light. I think a 15 or 20 ml version would be much better, but they didn’t have that size, so this is ok. Note that the small unit is 1/6 the size of the big one, so you need to do a lot more refills to get it clean. (Do not do this, it’s a bad idea, use only 60 ml syringes).

Pictures tell the story fine here, so here we go:

Here we have the filter and tube mod from Part 1, the small irrigation syringe, 10 ml, and the bigger one, notice how it has the tip? That tip will fit into the tube, making a snug and clean fitting. The 10 ml syringe can just be pushed against the tube, which is bigger than the syringe end on the inside, but it’s soft material so it fits well.

There’s the big one, with its tip stuck into the tube. Works perfectly.

You can see the old one that Sawyer included, that tip doesn’t fit into anything, and it’s hard to actually understand what Sawyer was thinking when they picked that unit.

And there’s the little unit. Takes 6 refills/plunges to equal one big one, but my feeling is because you don’t get a continuous stream of backflushing pressure, it’s probably not wise to only use the little syringe over time. (update: not only is it not wise, it’s a downright bad idea because it can lead to channeling inside the filter that can never be corrected, so use either the 60ml or nothing if you want your filter to last).

I did, by the way, try using two screw on ends with hoses, to try to use a bladder bag to backflush, but I couldn’t generate enough pressure, and it felt like I’d probably end up bursting the bag over time if I tried it, and it really didn’t get much more than a dribble when backflushing. You will come across people who suggest this in an attempt to save weight, but I strongly urge you to NOT follow that advice if you want your filter to last over time.

Make a Small Mesh Storage Bag

Now that’s it’s all done, I wanted a way to store it all, so I could put it in outside pockets without worrying about losing the prefilter elements, and also having the syringe there for easy access. I’ll usually store this in an outside pocket of my backpack, unless it’s going to be below freezing, then it has to go inside, and I’ll also include a small plastic bag to keep things dry inside the pack.

There’s the nylon mesh stuff sack, this one is made out of 0.9 ounce per yard nylon noseeum netting, you can use 0.7 oz yd. The stuff sack weighs 2.5 grams. Could be just a plastic bag, but this is more permanent, and doesn’t weigh much more than a plastic bag either.

And here it is with the Sawyer Squeeze cut down 16 ounce bag water scoop rolled around the filter inside the mesh bag, if you decided you want to do it that way.

And there you have it, some very easy and cheap mods for your Sawyer Squeeze filter.

Tips

Never let the Sawyer freeze, if you do, it has to be discarded to be safe. Sleep with it in your sleeping bag if it’s going to get cold at night.

Take the prefilter element out when backflushing it, you don’t want to trap gunk behind it, or accidentally pop the prefilter out and have to find it somewhere on the ground.

Carry a spare prefilter screen, it doesn’t weigh anything and you already have bought the coffee filter anyway.

23 Responses to “Sawyer Squeeze Filter Modifications Part 2 – Cleaning Syringes and Storage Bag”

  1. Tim says:

    You updated part 1 saying Sawyer’s squeeze bags for 2013 are stronger than their predecessors. Have you tried using one of these in place of a syringe with better results?

    Also, removing the washer and pre-filter screen every time you back-flush, then replacing it, is cumbersome, at least that’s what I found when replacing the original washer after I removed it to examine the filter. What if you simply screwed in the cut off business end of a drink bottle to hold the washer down while back flushing? I can’t imagine anything coming from inside the tubules will be greater than the 15-20 microns of the coffee filter and the back-flush water is getting filtered to 0.1 microns, anything that size or smaller should easily pass through the screen. Besides, this would help clear the sediment from the outer side of the coffee filter, wouldn’t it?

    Also, I read typical use of this filter (without a pre-filter) results in the eventual PERMANENT halving of the flow rate performance. Have you found that this Ace Hardware coffee filter protects the performance of the Sawyer filter?

    Lastly, do you find the Ace Hardware filter when free of debris noticeably reduces the squeeze filter’s flow rate, particularly when used in gravity mode, or is it about the same?

    Thank you for this informative article. Looking forward to your reply.

  2. h2 says:

    I haven’t had the opportunity to have used this stuff as much as I had hoped since I wrote that article, but let me answer from what I have seen so far:

    1: You can’t use a bag instead of a syringe, the pressure is not great enough to backflush out the gunk. Sawyer says inadequate backflushing results in the filter slowly failing over time, or losing the outer ring of filter material to clogging as the course of least resistance is developed over time and improper backflushing. You can by the way find 20 ml irrigation syringes, I’m not sure if those are big enough or pack enough force, but they are a lot smaller than the big 60ml ones. With the hose and adapter, you can get a decent amount of force with a smaller syringe.

    2: your idea of using just the cut off top of a pop bottle seems as good as anything I’ve heard to keep the filter in place, except it doesn’t make sense, you want the filter screen out so the water can flow out unimpeded in backflushing, along with its gunk, and you only backflush once a week, so that’s in fact not a very good idea at all in my opinion, the point is to wash it all out, not to trap it behind the pre filter screen. It’s not hard to put in the filter/washer, takes a few seconds, toss it in the filter bag while you backflush to avoid losing those light things, reinsert when done.

    3: I have no idea why anyone would use a .1 micron filter without a prefilter, that simply makes no sense to me at all. I don’t have enough trail miles with the filter to report on long term use, but I would always flush it on returning home anyway with the big 60ml syringe, a few times, then clean it out with a light bleach solution for storage. Also, by the way, hard tap water can gather in the tubes over time, so it pays to flush it with purified water now and then too, and I believe warmer water. If I were lucky enough to be able to do a longer hike, with a bounce box, I’d probably just toss the big 60ml syringe in that and use it, then pack it up again. The little 20ml seem to put out enough force however, even the 10ml is ok, but it doesn’t have a long stream, which might not backflush that well. I don’t know how many microns the ace hardware coffee filter it, but it’s going to keep out anything big enough to get stuck in there and start breaking apart over time, for example.

    4: I have found no particular change in flow of the filter with a screen in it. Easy to confirm, try it and see.

    In terms of backflushing, if you are getting water from fairly clear streams, you should really not need to backflush at all for a week, give or take, unless you are making water for two, then you should. I bring it with me to be on the safe side, but I haven’t needed the syringe yet while actually on the trail. But time will tell.

    In terms of the claimed life of the filter, I dont’ believe anyone in the real world will ever achieve that unless they use it perfectly, as directed, backflushing, cleaning, light bleach solution for storage, no hardwater at home, and so on, and even then I doubt it would last for a million gallons, but even if it only lasted for an order of magnitude less, ie, 100,000 gallons, that’s stunning for a filter, mind boggling, amazing. Assuming hot day, at 4 quarts a day, 1 gallon, that’s between 100,000 and 1 million days of use…. And if true viruses etc are expected, one can then after treat the filtered water with regular bleach, which is NOT safe for giardia, despite persistent internet misunderstanding between regular bleach and the stuff in purifying drops, but I believe bleach is fine for sub .1 micron organisms, which most people seem to agree are not real issues in the first world.

  3. Tim says:

    Thanks.

    I don’t believe the million gallon/10 year durability claimed by the company is anything more than presumptuous, unscientific, salesmanship hype. This concept is a fantastic idea, and the warranty is great if Sawyer actually follows through on it (how do differentiate between premature clogging from poor maintenance and a defective unit?), but I hardly see the durability claim as yet demonstrable. It would take almost 5 years of continuous back flushing to prove such a claim. I don’t think the filter has even been around that long, much less 10 years. Although, I do see it is being tested in the field by many tens of thousands of their customers as Sawyer says in their materials online. Mostly what I’ve heard in complaint from some of these “testers” is the original bags were breaking and the filter significantly loses flow rate over time.

    Sawyer has insisted that all the problems people have been having is due to not back flushing the filter well enough. If they had an effective 10-20 micron nylon mesh pre-filter (which Sawyer customer service has asserted is “unnecessary” and therefore “immoral” to sell with the filter, NONE of the problems their customers have been having would probably have been encountered in the first place, regardless of who is at fault. It boggles my mind why they wouldn’t unburden themselves of this crowd of infuriated complainers and just sell a $5,1/2 oz or less accessory inline pre-filter.

    If my memory serves me well, most sediment is between 50-100 microns, silt down to about 25 microns and iron (most foggy on this one) is above 10 microns. Sediment under 1000 microns that can get in the tubules can be rough at a microscopic level. The force of backwashing can theoretically force it against the tubules, scoring it and changing wall smoothness factor (e/D) which can increase friction of flow and reduce flow rate, especially if the turbulence is high enough. A rougher wall can also increase the possibility of debris getting trapped. Filtering relatively clean water should reduce the need for back flushing and make less likely any of the problems associated with improper customer maintenance. Yet Sawyer still maintains “it’s not needed”. I guess they would rather repeat that assertion until their market buries their product in the cemetery of public opinion.

    I intend to use my filter as a gravity feed system, so maybe I can permanently install your idea in the adapter at the bag. That way I would never have to remove anything from the filter except the adapter head.

    Thanks for your generous response. I appreciate it.

  4. h2 says:

    It’s important to keep sawyer’s claims in perspective, no other filter out there can get within several orders of magnitude of the filtration achieved from one sawyer filter. My old katadyne hiker claimed about 200 gallons but the screen starts looking pretty dirty after a lot less. Poison drops are poison, and also quite expensive per gallon. Steripen is an electronic device that is battery powered, I have to admit I cannot believe anyone uses something with so many possible modes of failure, the electronics could literally fail any moment, then you’d be drinking your live giardia filled water and not even realize it.

    I actually believe Sawyer when they say the failures are coming from improper use, for two reasons: anywhere with very hard tap water is going to cause the stored sawyer over time, not that much time probably, to fail and start slowing as the material builds up inside the tubes. Second, I can easily visualize those long distance big trail hikers ‘deciding they don’t need the weight of the big syringe’ to save a few grams, thus not bringing it. I can also see people doing it wrong, Sawyer’s syringe doesn’t really even fit into the sawyer, it works a lot better with the adapter and hose I use because then you can jam the syringe tip into the hose and plunge away, it works quite well. Even smaller nozzles on syringes like the 20ml one work pretty well when squished against the end of the hose, not the hard plastic of the sawyer itself.

    Personally I don’t really care if people don’t do it right and lose flow rate, if you offer somebody a way that does not have a fool proof system to do it, they will do it wrong, it’s almost a given nowadays. If I start getting slow flow rates, after knowing that I did it all right consistently, then I might take these ideas more seriously, but I don’t give a lot of credibility to the reports out there of slowing flows and failures, I’ve seen way too much terrible science and testing methods in the backpacking scene to trust anything unless it can be confirmed by someone you can trust.

    It would be interesting to see what someone who for sure takes proper care of the device gets in terms of useful life out of these things though, the problem is it would take decades to do the test. 100k gallons at 1 gallon a day is 274 years or so by my math.

    I believe these things have been tested at some point, enough to let them claim the numbers they claim, it probably wasn’t very realistic testing though.

    My impression of the filter, though I haven’t seen it inside, is that the tubes basically open up at .1 micron, so whatever fits in them, fits in them, and whatever doesn’t, rests against it and breaks into smaller pieces, some of which might fit after a while. I think this is why Sawyer claims no screen is necessary, but that’s just plain silly, as was their first amazing leaking bag. But even that one, to be fair, was probably squeezed too hard, you really do not need to squeeze the sawyer bag at all once it starts dripping through, it flows fine on its own as long as you hold the bag up above it. But squeeze that bag to make it go faster, and it’s going to fail. I wouldn’t trust it though myself, I’d rather use an evernew or an old platy that fits.

    By the way, reports are the 2013 model now fits platys again. Sawyer clearly isn’t the most clue filled company out there, they just find different ways to repackage that single filter device as far as I can tell, it’s just one of the products they sell.

  5. Tim says:

    There’s a guy on Youtube selling female to female coupling adapters for a receiving end water bladder. He’s charging an unbelievable $15 for it plus shipping. For $5 you can get the Sawyer adapter set at walmart and link them with an inch of 1/4″ hose. (probably why Sawyer never made one?) Or you can get polyethylene bonding epoxy, about 3/4″ of T8 flourescent tube cover, mate two bottle caps, drill a 1/4″ hole and add a couple potable washers.

  6. Tim says:

    I originally had a Katadyne Hiker as well. What a pain pumping through the sediment. One filter only lasted 460 miles of AT thru-hiking. You have to struggle with the thing like a snake, and then keep the dirty and clean parts apart to prevent contamination.

    The thing I like about the Sawyer is I can just fill up my bag, screw it on, then squeeze into my Gatorade bottles which are paracorded to my shoulder straps. Saves 11 oz dry and is much less complicated. It just needs at minimum an 80 mesh stainless steel garden hose strainer to keep out the big stuff that can lodge in the tubules.

    I’d rather not worry about whether or not my maintenance is perfect every time, and a prefilter helps eliminate that. You’d think Sawyer would likewise want to be able to stop having to listen to the complaints of those whose back flushing isn’t, according to their instructions, proper or adequate enough, haha.

  7. h2 says:

    The sawyer is a great invention, of all my UL gear, there are only a few pieces that I consider truly superior to the heavier old gear, ie, superior as in better without compromises, and the sawyer point one squeeze filter is one of them.

    I have to admit, of all the filtering methods, the poison drops that have to sit in the water 30 minutes to 2 hours to work strike me as the most ‘false weight savings’, with a sawyer, you can stop, filter a quart, drain it, on a hot day, filter a few more if needed, and walk on. ie, you can drink the next 2 hours of water roughly at the time of filtering, and then just carry what you need for after that. The poison method requires carrying that first quart or pint or whatever until it’s purified, then you drink that. Makes no sense to me.

    The use of a prefilter is something I came to appreciate with the hiker filter, it has that sponge pre filter, but that’s only I think about 150 microns? or so.But it worked ok.

    The sawyer really wins, as far as I’m concerned, if it lasted only a heavy backpacking year or two it would be a great deal, that’s still cheaper than all other alternatives per gallon. And since it’s unlikely it will only last a year or two, it’s really literally on a level of its own in terms of value with filtration, nothing is close. Sort of like the Big Dig ti trowel, or Peter’s Headnets in terms of value and uniqueness.

    I think the thing with backflushing isn’t that big a deal, if you do it every 7 days as a solo hiker with a prefillter, you should be good. My thinking is pop the 60ml backflush syringe into a bounce box for long hikes, or use a 20ml one, those are small, very light. My 20ml syringe weighs 14.5 grams.

  8. Tim says:

    I think the Sawyer filter is the best thing I’ve seen in hiking gear since the advent of LED flashlights and lithium batteries.

    I agree with your on the poison drops. I hike up to 30 miles a day and the last thing I want is to lug around 2 lbs of water in addition to quart I’m drinking. That might have worked fine in PA during the drought when we HAD to carry around 3 quarts, but not most of the time. Many of the hikers I saw carrying bleach drank right away, not realizing it takes time to disinfect cold water.

    I had the sponge on my Hiker. Don’t know what the micron rating was. It would have been better to have a 25 micron absolute to get most of the sediment. Those replacement filters are $50 now. You can get the Sawyer now for $30 at Walmart. That makes it a no brainer.

    Sawyer is right about “paths of least resistance” forming from weak back flushes. The outer diameter tubules clog and you can’t get them working again as a result. They want you to use their syringe for a quick and FULL flush with only one evacuation. The 60 ml is lighter, but you can’t evacuate the filter in one thrust due to its fractional volume. I’ve seen that guy on youtube flushing with his bag and adapter, but the trickle of water coming out the other end suggests he and his viewers will eventually clog their filters from not applying adequate pressure.

  9. Tim says:

    I’m sorry, not the 60 ml. The smaller syringes is what I meant.

  10. Tim says:

    Let me get back with you on how much volume is actually in the tubules. In retrospect, there probably isn’t that much dirty water in the actual tubules compared to the rest of the internal volume of the device. I know the inner dimension of the tubules is 1mm, and I’ve seen a photo of the tubule cross section giving an idea of how many there are per sq cm. I think the tubules are about 7 cm long.

  11. Tim says:

    Correction: The outer diameter of the tubule is about 1mm and the inner diameter is about .5 mm or 500 microns. (side note: if you want to keep potentially harmful large sediment out, you need a screen that has an absolute micron rating of about 250 microns).

    My first calculation is that there is about 13.7 ml of volume in the tubules if there are about 1000 tubules. I’ll have to check my work.

    But keep in mind, the water is entering the tubules at openings across their length, not one end, so 13.7 ml of syringe water is not sufficient to replace the dirty water. The flush water will merely mix/dilute rather than discretely replace the dirty water, so more than 13.7 ml would be required for the flush. I think maybe Sawyer reasoned that 60ml is needed to achieve a high level of dilution for one pass. They recommend to repeat flushing until the water flows clear.

    I was a little set back by the awkward mating of the supplied syringe and the exit nozzle. You’d think the mating should be nice and tight. Makes me think Sawyer took a shortcut, making me wonder where else they took shortcuts.

  12. h2 says:

    Since I’ve been collecting irrigation syringes, I was able to test the basic flows of the different sizes. You can buy 60 ml with a long nozzle tip, 20 ml with a long nozzle tip, and 35ml with a catheter tip. I just tested the 35 ml, which I believe can provide an adequate flow, but I was not able to get a good enough seal against either the tube or the direct connection to the sawyer, ie, pressing it against the sawyer, even with neoprene washers.

    You can however buy catheter to nozzle adapters, which would allow for a perfect fit to a hose.

    The flow of water from the 35 ml is in my opinion strong enough, but I think I agree with you that the 20ml may not provide enough quickly enough to be reliable.

    The 35ml is not that big, it’s about as long as the sawyer itself give or take. At home I always use the 60ml as directed, but I think I’ll see if I can pick up some catheter tip adapters then I’d carry the 35 ml. 35 ml size is harder to find though, you can order it online, along with catheter adapter tips, i found both yesterday at a medical supply place.

    I think re shortcuts, however, it’s quite obvious, they developed the filter core, and now simply rebrand it with different product setups, but both their flimsy bags and weird syringe that is just a generic medical product, not at all properly matched to the squeeze filter, shows pretty clearly that the sawyer group doesn’t reall put that much into this. For all I know, they simply licensed the core filter from the actual developer, and have never even really done the RD work at all, that would not surprise me to be honest.

    Re your numbers, I think you made a typo, keep in mind that:
    0.1 micron absolute hollow fiber membrane inline filter

    so the inner diameter is .1 microns, not 500. It can’t be bigger or it couldn’t filter to .1 microns.

    I tried to test how much a fairly dry sawyer required to fill the tubules across their length, but the water starts dripping through right away so it’s hard to measure.

    By the way, it looks like they have changed syringe type (hard to tell about size, I think I see a fuzzy 60 on that picture):
    sawyer image
    sawyer point 1

  13. Tim says:

    No, that’s not a typo. The inlet tubule is about 500 microns in diameter and the .1 micron is the exit piercing they made along the length of the tubule.

    The 500 micron tubules are full of dirty water, and that’s the volume I was concerned about in evacuating. You estimate the volume of dirty water needing evacuation by counting the number of 500 micron tubules. The rest of the water in the housing is clean.

    If you use a syringe that is 10-20 ml in volume, that won’t be enough to get all the dirty water out on the first pass. The dirty water will mix with the syringe water, and dilute the dirty water exponentially. One pass with consistent pressure of 60 ml will leave only a very small percentage of dirty water on the first pass.

  14. Tim says:

    Yeah, that’s a 60 ml syringe. It’s the same one I have, and I bought mine with the new sturdier bag at Walmart recently. Same brand, but the side shown in the picture reads “OZ” with 2 being the maximum.

  15. h2 says:

    After another backpackinglight thread on attempting to drop weight by using bags to backflush, I sat down to test, and now am going to revise the above postings to remove the suggestion to use any smaller syringe. I realized after checking flow rate, that a 2oz syringe provides a flow rate of almost 4 quarts per minute, and starts that flow rate immediately, ie, the moment you start squeezing down on the plunger, and then continues it for about 3 volumes of the tubules, actually for 4 if you ‘prime’ the sawyer backflush before starting it, ie, fill the tubules and outer chamber.

    Much as I do not like the large syringe, I am now going to stop testing smaller ones, it’s clear that 60ml is what was needed, at least. The long tip one weighs 36 grams, so from now on I will consider the weight of the sawyer to include that syringe for any trip over 3 days.

    Thanks for questioning some of these things, I’ll get these threads updated.

    The bpl thread on backflushing with bags made me realize that you cannot achieve a reliable backflush using any other method than the sawyer recommended one. Over time, inadequate flow rates, of 1 or 2 quarts per minute, as with a squeezed bag, will almost certainly form the channel that sawyer warns about.

  16. Tim says:

    Glad I could help.

    I like Sawyer’s application of dialysis technology to hiking filters, and anything anyone like you can do to help support Sawyer’s viewpoint on proper maintenance will help tremendously to keep this concept alive.

    The mating of the provided syringe is still a hassle, though. I’ve seen a YouTube video of a retailer (Steve @ HikeLight.com) who demonstrates how to do this, but it sure would be nice if someone could come up with a DYI way to mate the two effectively. I wish Sawyer would either manufacture a simple nozzle that screws into the syringe and narrows into the hole of the filter, or just make the hole of the inlet wider to seat the syringe nozzle into it. The latter simpler idea seems best to me.

  17. h2 says:

    sawyer squeeze with improved backflush

    This is how you do it with no error or issue. Since that’s a sawyer adapter, they could include that with that type of syringe, which weighs about 4 grams more than the catheter tipped one, and there would be no problems backflushing.

    There are catheter tip adapters I found online that thread in, that is a product that exists, to form the same nozzle, but that’s just more complicated and prone to failure (they are single use items technically), it’s easier to just use this syringe type, The problem here is that Sawyer simply did not engineer this at all, they just bought a generic catheter tip batch of 60ml irrigation syringes, and left it at that. To make this a reliable method they MUST create a solid fool proof system that works consistently. This is why, almost certainly, by the way, you hear those reports of channeling when backflushing.

    If you do what I did, you can get a super strong backflush of 2 oz in 1 second, every time, consistently. the hose / adapter weighs the same as their white sports nozzle thing, which I find silly personally, and is multiuse, since it does the following:

    1. fill clean bottle easily using hose
    2. Perfect fit for standard tip syringe for backflush, non catheter type
    3. perfect way to suck the sawyer dry and empty before packing it up. There was a discussion about this matter, people claimed you could not empty the sawyer and you’d be carrying around the water in the tubules, but I weighed mine after sucking water out and that claim is false, the water is out and the weight is precisely the same as it is dry, well, almost, except for a few stray drops.

    I can readily imagine the clumsy attempts by users to backflush using the sawyer provided directions, that’s unlikely to yield consistently strong backflushes, and is probably the cause of the slowi ng over time issue you noted.

    With a hose/tip/adapter you can use two hands to plunge the syringe, I found that with one hand, it was hard to get it plunged in under 1.25 or so seconds, estimate, with 2, 1 second every time.

    I tried, by the way, to use a neoprene gasket between the syringe and the sawyer but that didn’t work well, it would have to be glued to the syringe to work I believe, and even then it’s awkward since you must mate it perfectly against the sawyer body.

    Sawyer should do better work on their after filter thinking, their ‘bags’ for the squeeze were an instant internet joke, which means that those were simply not tested at all by sawyer, or they would have discovered this issue before release, the syringe likewise looks it was never tested by normal users, or it would not have been used either in that configuration.

    If you cut off the outer part of the catheter mating nozzle, leaving just the inner narrow nozzle, you can fit that easily into a hose end, but the seal of course you have to provide by pressure, but that’s a better seal than the hard plastic against hard plastic provides, it’s the same I got using the small syringes.

    Personally I consider this problem solved, it’s just a matter of sawyer changing their suggested method and including that adapter and hose in the kit. Those parts can’t cost them more than 25 cents.

    By the way, I now read that sawyer squeeze is at walmart for $29, though personally I refuse to buy anything from that store.

  18. h2 says:

    I will look for tubing that mates with the tubing I am using, it only needs about 1mm larger inner diameter to fit over the catheter tip.

    I can find such stuff at medical supply houses. But the device would still require the female blue adapter piece.

    I checked to see if the blue tip of the adapter fits into the catheter tip, it does, but the fit is just not quite tight enough, and the water squirts out. I believe the adapter / hose / long tipped syringe is the best solution so far, I’ll see if I can find a way to use the catheter tip syringe however, the right hosing size should do it.

  19. Tim says:

    Thanks for the experiments. That information is very helpful. With my old Pur filter (now the Katadyn Hiker, I always blew out as much water as I could so as to not have to carry it around. 2179 miles with an extra 3-4oz is the feather that can break a camel’s back. It’s good to know you can get all the water out of the Sawyer.

    I knew Walmart sold Sawyer gear online, and I got lucky to find one Sawyer Squeeze at the store near my house. It had the new single quart bag, the 2 oz syringe and the filter for around $29. I also got the adapter set for $5 and some of Sawyer’s premium insect repellents, but had to get those ship to store.

  20. Tim says:

    I cannibalized some old gear to modify my Sawyer Squeeze filter for gravity filtering.

    For the head pressure, I used 32 inches of 1/4″ ID hose (under 1.5oz) from my old Platypus hydration pack to fit between the $5 Sawyer adapters they make for this filter. This tube goes between the filter and the dirty water bag.

    I also attached the 4″ quick connect hose from the clean end of the the Katadyn Hiker filter to the clean end of the Sawyer filter. (I could use the male quick connect at the 3L Platy bag for hands free catching of the clean water.)

    Then I purchased a 3-pack of Camco 50×60 mesh (300 micron absolute I believe) stainless steel inline garden hose sediment filter/washers “ship to store” from Ace Hardware for $3.25. (You can get these from Lowes for a $1 cheaper, but Ace could get them to me faster).

    I took the 50 micron sediment “filter protector” nylon screen mesh from the Katadyn Hiker filter, traced the washer from the Sawyer filter on it, and cut a circular sheet to fit inside the dirty end of the Sawyer, placed the Camco filter washer mesh side out on top of that and seated it with a jewelers screwdriver (which also works to successfully unseat it). It doesn’t leak when the adapter is twisted into the washer. That connection is intended to remain secured at all times.

    Theoretically now, nothing more than 50 microns will get into the ~500 micron filter tubules, and anything that did get in can also pass through the mesh when backflushed out. The inline washer/screen keeps out large organic material and fine sand to keep the 50 micron nylon screen free to work with most of the finer sediment (>150um), rust flakes >74um) clay (>44um) and and silt (>37um).

    The 60 ml syringe mates by pressure to the male quick connect at the clean end. I had a 50 cent 3/8″ diameter black rubber washer from Lowes that fits snugly around the inner nipple of the syringe and seating against the outer nipple. This gives me an airtight seal when pressed to the quick connect end. So tight in fact, that when I push air through the filter to get all the water out, it causes the syringe to kick back.

    Although I haven’t yet tested it in the field, I have run tap water through it several times. I filled the 1 L squeeze bag to the rim, twisted it secure to the adapter, turned it upside down into gravity feed orientation, and gave it a squeeze to get the filter primed and flowing. It consistently takes 53 seconds to evacuate 1 liter.

    Since I intend to backflush after every filtering stop (makes sense for most people who would do this to simply evacuate the several ounces of water weight from the filter), I expect my DIY pre-filter to be free of sediment with each filtering stop. Thus, I would expect to have consistent 1L/min flow rate in the field. That’s still better than the best flow rate of the Katadyn Hiker (1L/90sec) and no pumping or squeezing (except for the priming squeeze).

  21. Tim says:

    I’m informed by the Katadyn staffers in Switzerland that the nylon filter screen provided to keep sediment out of the Hiker/HIker Pro filter cartridge is actually 41 microns, not 50 as I stated earlier. Even better, as that pore size traps all the dissolved clay and most of the finest silt.

  22. Jon says:

    I have found 12″x12″ sheets of Nylon 6/6 mesh in both 50 micron and 30 mircron. They cost about $11 each. Would it be better to go with the 30 micron or do you think the 50 micron is okay? If I understand what Tim is saying in his latest post is to put the nylon mesh in first, then the Sawyer or thinner neoprene washer, then the Camco S/S mesh goes on top of that?

  23. h2 says:

    I wouldn’t use two meshes in a sandwich, that is very likely to just clog the flow completely.

    I’ve also found online medical materials supply houses that sell mesh in specific micron sizes, that’s a good resource although of course you need so little mesh to begin with that it’s hard to justify buying the square foot, unless you are going to pass filter screens along to people out there.

    I don’t know what the nylon coffee screen mesh is in terms of microns, I wish I did, because I do know it slows the flow significantly. If money isn’t a problem for you, I’d get both sizes, 30 and 50 microns, and experiment.

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