The "Philter"

[SPSheep]

Some may remember my trials and tribulations with 12 gram CO2 chargers containing metal shavings. After multiple orders, I now Have ~700 chargers that, when used, compromise cup seals with bits of metal. Not wanting the chargers to go to waste, I got to thinking: what if I could keep the shavings from reaching the cup seal? I'd need a filter. Or, in keeping with Phantom nomenclature, a "Philter".

Screenshot 2026-06-04 204845.png My initial inspiration was this device from AGD, which was a sintered copper filter that was screwed into the CO2 line (I think).

IMG_9232.jpg After too much time browsing McMaster Carr, I decided on a design. Something simple, just a metal frit (the middle disc) sandwiched between two hollow set screws mounted directly in the Phantom pierce pin assembly (downstream from the pierce pin itself).
image3.jpgThe assembly, drilled and tapped (poorly, but hey it works).
image1.jpgThe whole thing screwed together. I gassed the gun up and everything seems to work. The frit hasn't deformed from the pressure, and there aren't any leaks. The only thing of note is swelling on the bottom o-ring, but I think that may just be CO2 interacting with the buna material of the o-ring itself. Anyways, here's hoping it keeps working: with the number of chargers I own I'll be set for the next decade at least!

[flyweightnate]

This is exactly what a lot of the 90s guns used, when CO2 was still really popular. Another spot to put them is sandwiched between a macro/ compression fitting and the bottom of the hole it threads into, if you're running a hose.

Cool plan to seat it in the bucket. Teflon washers are the way to go if that buna ring fails. No free carbon means nothing to react with the supercrit gas when you get up to summer temps.

What size set screw did you use?

[SPSheep]

I used 5/16"-18 set screws, which hold a 1/4" diameter 20 micron frit. And thanks for the info about the teflon o-rings, I'll get some on order!

[Sottyman]

Is this a service you'd be willing to provide?

Also, I wonder you're already in there if there's a way to stuff a check valve setup as well. Like the White Wolf oring and ball bearing so the gun doesn't degas when dumping a 12 gram?

[SPSheep]

My machining skills are amateur at best, so not at the moment. I'd be too worried about damaging someone else's stuff. It's pretty simple to do if you have access to a drill press, though. I used an "F" drill bit and a 5/16"-18 bottoming tap for the threads (with thread cutting oil), then sandwiched the 1/4 inch diameter 20 micron frit in between two 5/16"-18 hollow set screws (each 5/32" long). I believe I tapped .450" worth of threads. You just need to make sure you don't drill through the threads that hold the pierce pin. All parts can be ordered from McMaster Carr. Also, interesting idea about a check valve, I'll have to give that a look. Thanks!

[Trbo323]

That's a fantastic solution. Well done

Sent from my motorola edge 2024 using Tapatalk

[SPSheep]

Thanks!