I was wrong! I had hand tightened a Platypus Hoser to the Sawyer and it felt like it was sealing, but after comparing the threads of the Hoser with the Sawyer bag, I did a real-world test and it leaks. Of course the leak runs right down the side of the filter and would drop dirty water straight into any container below. Testing several Platy bags that I have, most bottomed out with the Platy neck at a noticeable angle in the filter housing-- NOT good! From what I can see, the Sawyer filter and Platypus bags are NOT compatible. I think repeated use would eventually damage the threads on the filter and I don't recommend using the Platypus products on the dirty water end, even if you can get a good seal. It's too bad, as that would really extend the options with the Sawyer.

As you can see from the photo, the Sawyer threads are closer together, a finer pitch thread.

Sawyer on the left, Platy on the right.

Edited by dwambaugh on 10/22/2011 08:05:02 MDT.

thats good to know about the bags. my main reason for buying this filter wouldbe speed. i currently wait for chems/(hike carrying a few extra pounds for 30 min). If im forced to use those bags, i think i'll stay with what i got: Homemade carbon filter + bleach.

The speed and weight were my rationale for buying it. It is close to a Steripen for weight and free of the battery issues, but still prone to mechanical issues like the bag breaking or the filter clogging. I can't imagine someone not wanting to roll the bag as it empties. Looks like we should avoid hard crumpling of the bag.

@Martin:

I did not intentionally attempt backflush in the field, but I managed to *unintentionally* backflush quite a bit by being a klutz - ended up squirting quite a bit of water back into the Sawyer bag. I have since backflushed it at home with a clean 1L Platy to prepare for storage. There's a little bit of water that comes under the edge of the cap (where it meets the filter) when backflushing under pressure (as hard as I could squeeze), but not much (most of the water goes through), and no leakage between the taped caps.

I should point out that while this has turned out to be pretty robust so far, I didn't just assume it would be fail-proof. I also carry one 1L Platy fitted with the squirt top that came with the Sawyer system (that I use for handwashing, etc.), so that if the connector failed in the field, I could use that squirt top on the filter to get water into a clean Platypus if needed. I looked at this as a convenience thing because the squirting was irritating - I was surprised it held up so well!

I came up with this idea the night before a trip, so there was no time to get a tornado tube (though I had read about them here), but it certainly makes sense to try that. Also, it sounds like you have more skills and tools than I do...

@Dale: Thanks for testing that - that's a real drag that the Platypus bags don't work on the dirty end. I wish Sawyer would develop a stronger bag, or more compatible threads...

I tested using a Platypus 2.5 liter as the dirty water bag, and I did not observe any leaks, despite rolling and squeezing very hard. Also, if I put the Sawyer bag lid on the Platy and squeeze very hard, no air escapes. Some possible reasons my results differ from Dale's:

1. My Platy has a slightly courser thread pitch (spacing) than the Sawyer bag, but the threads themselves do not appear to be as thick as the ones in Dale's photos. My Platy was purchased in spring, 2010. It's possible that Dale has an older or newer Platy, and the threads changed slightly at some point.

2. My filter has a white washer inside, and I tightened the Platy very snug against it. Maybe the washer is something Sawyer added or changed? Maybe Dale didn't have the Platy as tight?

3. Dale wrings his Platys just like Stephen wrings his Sawyer bags. ;)

"My Platy was purchased in spring, 2010. It's possible that Dale has an older or newer Platy, and the threads changed slightly at some point."

And/or Sawyer has some variations in tolerances too, just to make this all fun.

I tried several Platys, one that is a couple weeks old to me, but who knows how long it was on the shelf. The rest are from a span of years. All are pretty much the same threads except that 34oz Platy "SoftBottle" that has thinner threads (and still doesn't work).

My filter has a white washer too. Looks just like a garden hose washer. It makes me feel very special.

I'm pretty good mechanically-- automobiles, cars, bikes, boats, appliances and plumbing, and when I tighten a Platy into the filter, it seats at a distinct angle and does not feel right when it starts to tighten down. Every mechanic fiber in my being says "STOP, IT WILL STRIP."

Like many things, you could make it work, but I think it would get damaged with use, and when you let all the "use" out, it becomes "useless." :)

The Platy on a Sawyer, note the "unnatural" angle:


the Sawyer bag on the Sawyer filter and all right with the world:

Hey Dale,

The fix is a neoprene washer as stated above. It will allow your Platy threads to seat deeper into the female Sawyer threads and it will grab the Platy threads with no leaks. Cost = 39 cents.

The Platy I have screws straight on to my filter. I don't sense any tendency for it to go on at an angle at all. It's this one:

http://cascadedesigns.com/platypus/water-bottles/platy-bottle/product

Mine isn't as transparent as the photo on that page--just appears to be a standard Platy.

I guess the important point of all of this is that if it's going to leak, it will be pretty obvious beforehand. :)

Edited by AndyF on 10/22/2011 20:39:00 MDT.

OK, so I had to try this. Put a recently purchased 2L Platy (what I had intended to use as a dirty bag if the Sawyer bag gave out) on the dirty end of the filter. Not as crooked as Dale's, but still crooked, and leaks after a little while.

Guess I'll be babying the Sawyer bags, and maybe ordering some replacements just in case...

Bill wrote, "Hey Dale,

The fix is a neoprene washer as stated above. It will allow your Platy threads to seat deeper into the female Sawyer threads and it will grab the Platy threads with no leaks. Cost = 39 cents."

I tried it with no washer with the same off-center result. With the items I have on hand, the washer won't be an effective cure in my opinion. I suspect there are a couple variations on threads with the filters and perhaps the Platypus bags and/or I have the wrong side of the bell curve on manufacturing. I really do think that I would eventually damage the filter threads if I continued to use the Platypus bags. Thanks for the tip though!

The filter works as advertised with the Sawyer bags. Of course I assumed that I could hook up a Platypus when I felt like it and I had a gravity option in mind too. For now I don't see that as an option and I can't fault Sawyer for that.

A proper fitting hose nipple would be a great accessory for Sawyer to sell and would allow all kinds of adaptations from there. I have to see what the hardware store has to offer.

Update:

I went to the hardware store and found that the threads are very close to a standard US 3/4" garden hose fittings. I found a couple plastic fittings with 3/4" male garden hose threads and barbed hose fitting on the other end, but the barbed end was too big for use with typical hydration hoses. I'm fairly confident that you could find ones with smaller barbed fittings or something like a 3/4" male hose to 3/8" female pipe bushing, and that would allow using available pipe-to-barbed fittings that come in just about every size imaginable.

But....the 3/4" hose threads still aren't a perfect match, as I tried some metal fittings and they were going to strip and I could see that they were doing some damage to the filter threads. These aren't high precision fittings, so it is a real turkey shoot to see what will fit and it still needs some testing under real-world conditions.

My take is that the Sawyer threads are proprietary and it is best just to stick with their bags. If you want to use a hose-and-bladder arrangement, the Sawyer filters that come with hose nipples are available.

Indeed.

I tested the cap from standard 1.25 L pop bottle. The thread seems to match the Sawyer perfectly.

So I took two flexible caps, drilled 6 mm holes in the middle of each one, and crimped a 6 mm eyelet through them (with washer). Worked perfectly to connect the **output** of the Sawyer squeeze filter to a pop bottle.

Add a small bit of duct tape doubled over to one bottom corner of the sawyer bag and punch a hole in the duct tape. Add string to suspend the whole system from anything. Fill Sawyer bag, connect to filter inlet, connect filter output to pop bottle, hang up. Walk away and let it filter.

This has some potential...

Cheers

I took mine out last weekend and was thinking of ways to use it for multiple people too, and then a friend asked how she could use one to support 3.

So night before last I hacked out a couple ways to use the Sawyer Squeeze as a multi-person, platy-filling filter system.



The top one I pull the nozzle off and slide a tube onto the outlet barb that is exposed. The other end has a Platy adapter. This lets a bottle stand a little easier. (I can use a longer tube too.)

The bottom one (like you and others I see) is two Platy caps that I roughed up with some emery cloth on the faces and then glued together with silicone caulk. I drilled a 3/8" hole through the center of both caps. This just lets the Sawyer attach directly to a Platy of any type.

I will try it out this weekend.

Like you Roger, I was thinking about a gravity application as that has become my favorite these days. For a single user I suppose the 2L bag is enough but I want to figure a way to use something A; bigger capacity, and B; easier to fill.

I have the gravity Sawyer system with the Platy Big zip and thought of converting to this..however....while in the Sawyer website I enlarged the image and noticed the bag said if the filter freezes, discard because it's no good. So...is this true of all the Sawyer filters? And has anyone experienced this with theirs? And why would freezing the filter render it no good? Do they mean even after thawing?

Donna said:
"I have the gravity Sawyer system with the Platy Big zip and thought of converting to this..however....while in the Sawyer website I enlarged the image and noticed the bag said if the filter freezes, discard because it's no good. So...is this true of all the Sawyer filters? And has anyone experienced this with theirs? And why would freezing the filter render it no good? Do they mean even after thawing?"

Donna, I believe the issue is with the expansion of freezing water rupturing the hollow fibers. My understanding (or at least the way I visualize it--which may be wrong) is that these filters have thin tubes that in turn have a uniform pore size along their walls that actually does the filtering. Expand the water by freezing, and the tubes break, allowing water to leak from the broken fibers rather than being forced to filter through the pores.

FWIW, the MSR and Playpus filters that use HFMs also have the same warning. The problem is, is that you would probably not know the filter was damaged as larger particulate matter might still be filtered while the microscopic germs would not...that is, until you get sick.

Edited by BER on 10/26/2011 10:56:34 MDT.

...bursting all the little 0.1 filter fibers. Then all the badies come right through it!

Yeah, Brian is right.

Think of a drinking straw made of hard plastic with a bunch of holes poked in it that are sewing pin sized. Those holes are the 0.1 filter holes. If the straw freezes it breaks and lets things larger than 0.1 get into the straw and out to your receptacle.

I had to sleep with my Squeeze last weekend and plan to this week too.

It seems like there would be no way to know if it froze unless you put a small water bottle with you in your bag/quilt and the filter. If the water froze, then perhaps the filter did as well.

I'm just curious if anyone uses a prefilter (such as a disk from a gold mesh coffee filter ala this thread ) to keep larger sediment out of the filter? Perhaps putting the disk under the washer inside the inflow of the filter?

I've been thinking on the way I manage water filtration, and finally got around to getting this system. It should cut a significant amount of weight compared to the MSR Aultoflow gravity system I'd previously been using.

Edited by BER on 10/26/2011 14:11:20 MDT.