Hi DIY punks! I need a little help with something. I’ve been trying all sorts of ways to home carbonate things as sustainably as possible. Most have not really worked out as intended, but I’m really really close on this latest attempt. This version is to connect a CO2 tank to a whipped cream dispenser.
Basically, the path from the tank looks like this:
- 5 lb CO2 tank → dual gauge primary regulator.
- Regulator → 5/16" hose.
- 5/16" hose → 5/16" barb to 1/8"NPT male.
- 1/8"NPT male → 1/8"NPT female to 8mm female quick disconnect.
- 8mm female quick disconnect → 8mm male quick disconnect to 3/8"-24UNF female.
…and the path from the dispenser looks like this:
- 1Qrt ISI Gourmet Whip M22 Male → M22 Female.
- M22 Female → “mystery hose”.
- “Mystery hose” → “Mystery connection” male.
So, I need an adapter to hook up the 3/8"-24UNF female to the mystery connection. It seems to start screwing in for a couple turns, but then won’t go any further, so my guess is that it’s the same diameter with different threading? Note that, in the link for the mystery hookup, I removed the TR21-4 at the end, because that’s for directly hooking up to a small tank. The mystery connection I’m talking about is the male threaded part you can see screwing into the TR21-4 connector.
It doesn’t seem like many people are doing this, or know what most of the industry standard connections actually are. See this thread here for example. Consequently, I have no idea if the mystery eBay hookup I bought even works, despite that being its entire purpose. The interior of the CO2 cartridge puncturing mechanism is a black box to me, so I’m just trusting this M22 connection is all that’s required. There’s definitely some kind of one-way valve in there, but hopefully it doesn’t somehow require being “pushed” by the cartridge itself.
UPDATE: So the 8mm male quick disconnect to 1/8 NPT female adapter worked! Everything now hooks up to everything else just fine. Unfortunately, there’s a new problem.
I have no idea how the gas valve built into the isi Whip works, but this hookup doesn’t seem capable of pushing any CO2 through it! Everything else works, there’s no leaks, and gas can make it all the way through the hose and out the end. But as soon as I screw it onto the isi’s gas hookup, it can’t get through. There’s a video of an isi disassembly here that shows what the valve looks like inside, but I can’t tell much from it. Clearly this thing is some sort of one-way valve, since gas doesn’t escape when you remove a CO2 cartridge… But what’s so special about a cartridge that my janky hookup doesn’t match?
As far as I can tell, nothing in the mechanism budges when you push on it. I don’t think it’s being mechanically opened by screwing the cartridge in. Is it possible that it just requires the explosive amount of pressure released by a punctured CO2 cartridge before it’ll open? I’ve been feeding it 30 PSI. Some quick googling tells me that 8g cartridges usually release 850 to 1100 PSI. Should I just try cranking up the pressure until something happens? I think the problem then becomes, there’s substantially more than 8g of CO2 in my tank… What happens then?
Now, I’ve since stumbled onto this post about just straight up removing the built-in gas hookup and replacing it with a sanke to ball lock conversion kit. That seems like it might be way better than the approach I’ve been using, and I wish I had seen it earlier!
Looks like a compression fitting to me
That would explain the nut looking thing, right? Does it being a compression fitting matter insofar as the specific type of thread/diameter is concerned? I don’t really know anything about them, but a cursory Wiki skimming makes them seem complicated and delicate. Could I have potentially messed it up at all by removing it from the TR21-4 it was originally screwed into? It was quite hard to remove.
Looks like 3/8" NPT Schrader valve connection to me, but I’m not an expert on the matter.
I think you’re right! Rather than find some kind of NPT to UNF adapter and throw yet another (potentially leaky) connection into the mix, I’m going to try replacing the “8mm male quick disconnect to 3/8 UNF female” with a “8mm male quick disconnect to 3/8 NPT female”. Specifically this one, I think. Wish me luck. an thank you!!
EDIT: Or maybe this one.
Thanks. I hope it works out!
You seem like you know what you’re doing, but since you mentioned it:
If you’re worried about leaks, you can use Nylog White on the threads. It’s food rated and works for your liquid and co2 gas connections. In theory, it’s also not supposed to harden and make your fittings impossible to unscrew.
Oh I definitely have like zero idea what I’m doing, but hopefully I’ll learn a thing or two in the process lol. I will definitely be picking up some Nylog White, thanks!
So, the 3/8 turned out to be WAYYY too big! I was just kind of naively taking it on faith because the listing said that’s what it was… I think it’s actually 1/8 instead? We’ll see once the new part arrives. Shame on me for trusting a thumbnail from AliExpress over, you know, a ruler 😅
