Sawyer Squeeze/Mini & Hydrapak adaptive fitting

Or would it be worth it to just pick up a CNOC bladder to get the big opening?

There are lots of concerns related to 3D printing and food safety although some of these are diminished by putting the printed part upstream of the filter like you are proposing. That said, My vote is to go with the CNOC bladder and eliminate a part and potential failure point.

A less-sophisticated way to fabricate such an adapter: make a ~28mm dia hole in a hydrapak lid for the smaller fitting top. It shouldn’t be too hard to locate such a common fitting, maybe one already lying around the house, or at the grocery store. The critical piece would be finding/making an appropriate sized silicone gasket for the seal. No fancy tools needed for construction: marker, screwdriver, box cutter, round file….

I did something similar recently, but went the opposite way and made an adapter so I could use my befree filter with an old faithful msr dromedary. I procured a hdpe nalgene lid from my wife’s lab; for inner fitting, I sacrificed a 1L hydrapak that had either developed pinhole leaks soon after I bought it… or maybe it came that way from an rei outlet; a spare silicone gasket off an old water bottle lid fit perfectly between. Soaking the two pieces in a bath of boiling water helped me to push them together. Photo:

bonus thought: if you have an old/retired befree filter lying around, it may be easier to remove the bottom cage/membrane. I think what you’d be left with is essentially what you’re after. This is assuming the sawyer fits the top threading of the befree. Disclaimer: I haven’t tried this. If you do, let us know how it works out!

This would be pretty cheap and easy to do if you can get the specifications on the threads.  Sketch something up on Tinkercad.  They have a thread tool that is pretty easy to use, then upload the drawing to Shapeways.  It would probably cost under $10 shipped.  The biggest issue (as was mentioned above) anything 3D printed is not food safe.  Even if you were to use food safe plastic in a food safe printer, the resulting part would have many small cracks and crevices that would be a breading ground for bacteria and microbes.  It shouldn’t be anything your filter can’t take care of, but I would give the part a nice sealing coat of food grade flowable RTV.  I am NOT an expert in food safety so try at your own risk.  Let me know if you need any help with Tinkercad.

https://backpackinglight.com/forums/topic/adapting-components-befree-to-squeeze/

Hydrapak plug-n-play cap > 5cm hose with sawyer adapter > filter ???