How Do I Find A Co2 Dealer?

[waterdrop]

Do any of you have tips for going out there and laying the groundwork for having a good place to get and have your CO2 cylinder refilled with CO2? I feel like I need to figure this out as a kind of baseline thing before I take on the other tasks of researching the best individual parts and devices to put together a really nice CO2 system.

Is it my imagination or am I remembering correctly some threads from people saying that they were finding that some of the suppliers are turning away hobbyists because it's just not worth their time to deal with small, periodic individual sales? This would be a terrible thing if it's somehow on the increase.

I live in a small college town in the middle of North Carolina, USA, and I'm imagining the places I should start considering are welding suppliers, soda industry suppliers and perhaps gas suppliers to university laboratories. Am I overlooking other possibilities?

What factors lead to success in finding a good supplier? Is it all hit or miss? Should I compile a list and then physically go and visit them to add the chance that they might be less likely to turn me down if I'm right there talking to them?

I don't even know what it's like for most of you when you go and get your bottle refilled. Is there some nice old man who reminds you of the safety tips while he turns the knobs on some contraption that hisses and fills your big cylinder? What does it cost?

I also have this feeling that the experience may be different here in the states versus over in the UK. Have any of you long-timers in planted detected that sort of difference?

WD

 

[GrayScale]

Welding supply shops, beverage companies, or (it's kind of a hit or miss if they have the attachment but) sports stores that sell paintball guns.

You can find them in a phone directory or just have a google search for "local welding shops" etc... Give them a call and ask if they fill 5lbs co2 cylinders.

Some places don't actually fill the cylinder but swap your empty one out for a different filled one.

 

[waterdrop]

Thanks GrayScale, yes, I really wouldn't care if they just swapped out cylinders each time I went in. I think I've heard some people saying that that is common, that a lot of places have you buy the cylinder first but then they will swap from then on or something?

I confess I'm also curious what the filling process is like. Can it be as simple as your cylinder being set next to a larger one with the right connection between and then a knob turned? Could those big standing ones you see sometimes have so much higher pressure that they could fill yours to it's correct capacity and pressure and not have emptied themselves too much?

What -is- the pressure and volume of a typical hobbyist cylinder anyway?

WD

 

[GrayScale]

I think it all really depends. It seems quite a few people have turned to fire extinguishers.

For normal compressed co2 cylinders I'm pretty sure the volume is described by size. IE: a paintball co2 cylinder can be as little as 2 grams or as large as 20oz.

Gas is measured by psi which can be measured using a regulator. They also come equipped with blow off valves so they don't compress gas past a certain psi (I may be wrong). In saying this, a 5lbs cylinder doesn't refer to the weight Of the cylinder itself but it can hold up to 5psi in volume of compressed gas. When I played paintball, they used large co2 cylinders (the giant stand up ones much like a helium tank for balloons) to fill the co2. Once it reaches it's max compression the excess blows out of the blow off valve and the big canister was closed off. Again I can't remember about the blow off since it's been 5 years since I've played. The attachment nozzle may have a built in regulator to measure the pressure in the tank while it's filling. But since co2 cylinders have an open and closed valve and it should be closed for filling, the blow off would make more sense since it is located below the knob.

 

[waterdrop]

Oh that's a really good description. I hadn't thought of it that way. So the source is pressing in a bunch of pressurized gas and the blow off thing is a valve that will hiss and start releasing excess when it's preset limit is reached, thus tipping you off with sound that it's time to stop! I was sort of thinking of blow off valves as some sort of horrible one-time rubber plug that would explode across the room and everything in the cylinder would escape out all so that the metal wouldn't explode (the cylinders themselves have those sorts of safety things too don't they?? I seem to remember those in one discussion.)

But your description of a -reusable- blow off valve (and on the stem, above the cylinder but below the shutoff knob for the cylinder makes so much sense.. I don't know why I hadn't thought of it that way before!

WD

 

[GrayScale]

Those "horrible" blow off valves what you thought are the same thing. If you drop the tank with all the compressed gas in it and the shutoff knob or blow off valve breaks, the pressure from inside the canister would shoot out creating a torpedo. But rest assured, those things don't break unless it's dropped.

 

[waterdrop]

Where are all those planted people who have refilled tanks? I'm still curious for stories about what it is actually like. All the boring details. Is it a flexible hose like filling a car tire that comes up to the tank (heck I don't even know what the fill-point on a tank looks like or where you disconnect it from your own tank gear at home!

WD

 

[Mikaila31]

Well I'm not totally par on how they fill them... I just give them my tank and they either fill it or give me a new one . Anyway it does require a MUCH larger tank to fill a small tank. Tank to be filled is frozen first, make it really cold because this allows the gass to be packed into it. Colder temp=smaller volume. My paintball tanks take 5-10 minuets to fill and I'm pretty sure most of it is the freezing process. After they are filled they are very cold for a good hour. I swap my big tanks at a company called airgas. Not alot of the welding supply places will fill tanks, because it is extra cost to have the stuff needed to fill them. Most around here send them to the metro area then they get sent back to the shops which takes a few days. Most shops stock the common sizes and prefer to swap out your tank as this can be done in a few minuets. You don't HAVE to buy your tank from the place you get it filled. As long as it is a newish tank they should accept it. Don't buy any with coca-cola stamps on them as not everyone will fill these. Means they were once owned by coca and coca cola has a habit of loosing track of these things lol. I don't see why they would not fill a small 5lb tank. These are commonly used for at home hobbyist brewers as well as aquarium. When you first go in either buy a tank or bring one in, they will set an account up for you and basically you own A tank, that is the same size. It is not the same one you originally bought either. Its whatever one is currently in your possession. I have no idea where the original 5lb tank I bought and paid for is. Everytime a tank is swapped ownership transfers to the full tank and I am under no obligation to ever bring it back since all I am paying for it the CO2. They only see me every few months and I've never had any issues. Make sure you buy a tank and don't rent a tank. A 5lb CO2 tank costs about $65 as a decent price online. Locally might be like $75ish to buy a tank. There are a few one time fees I believe when you set your account up, like maybe $5 extra with the place I use. I bought my 5lB tank empty from aquariumplants.com If you need to order some plants or something too its good too sneak a canister in there. Then just swap it locally, or you can buy directly from your local place.

 

[waterdrop]

Mikaila, wonderful, wonderful, exactly the kind of post I was hoping for, lots of details! Quite interesting, I've never heard of the thing of getting them cold first, makes sense though. And Airgas is a name I've seen on plenty of trucks (see you are in the states like me.) Makes sense a lot of places might just be drop-off depots too, and you'd just get the swap and never see your tank actually get filled.

How did you ever figure out about the airgas place to begin with?

WD

 

[shasm]

The reason for the freezing is to condense the co2, thus lowering the pressure. There is a pressure/temperature relaionship for gases. See Boyles Law. As a gas expands it releases heat. The more it expands the more heat it gives up. In a presurized bottle there is liquid and gas depending upon pressure and temp. This can get deep but this is the basic principles that modern air conditioning use. At 80F in an enclosed bottle the pressure would be 969psia. There is a fill point to leave room for expansion so as not to blow the safety.

 

[GrayScale]

The reason for the freezing is to condense the co2, thus lowering the pressure. There is a pressure/temperature relaionship for gases. See Boyles Law. As a gas expands it releases heat. The more it expands the more heat it gives up. In a presurized bottle there is liquid and gas depending upon pressure and temp. This can get deep but this is the basic principles that modern air conditioning use. At 80F in an enclosed bottle the pressure would be 969psia. There is a fill point to leave room for expansion so as not to blow the safety.

You make a good point however co2 does not have a liquid state, hence why it can be so cold and not turn to liquid. It only comes in the form of dry ice, which it has to be lowered to a certain temp before it changes. Any warmer than that temp it just changes back into a gas. It is this property of co2 that makes injecting it into water so difficult. When it's diffused, it comes out in tiny micro bubbles and dissolves into the water. I'm not quite sure how they make the liquid co2 but I'm sure most of it is water with dissolved co2 in it.

 

[lljdma06]

The reason for the freezing is to condense the co2, thus lowering the pressure. There is a pressure/temperature relaionship for gases. See Boyles Law. As a gas expands it releases heat. The more it expands the more heat it gives up. In a presurized bottle there is liquid and gas depending upon pressure and temp. This can get deep but this is the basic principles that modern air conditioning use. At 80F in an enclosed bottle the pressure would be 969psia. There is a fill point to leave room for expansion so as not to blow the safety.

You make a good point however co2 does not have a liquid state, hence why it can be so cold and not turn to liquid. It only comes in the form of dry ice, which it has to be lowered to a certain temp before it changes. Any warmer than that temp it just changes back into a gas. It is this property of co2 that makes injecting it into water so difficult. When it's diffused, it comes out in tiny micro bubbles and dissolves into the water. I'm not quite sure how they make the liquid co2 but I'm sure most of it is water with dissolved co2 in it.

The liquid form of Carbon that we dose is not actually CO2, but liquid organic Carbon if memory serves. Not the same thing. When you dose via yeast production or with pressurized you are dosing the gas Carbon dioxide. The liquid Carbon is a different animal entirely, but can be utilized by plants as well. Plants are such versatile things.

 

[waterdrop]

The reason for the freezing is to condense the co2, thus lowering the pressure. There is a pressure/temperature relaionship for gases. See Boyles Law. As a gas expands it releases heat. The more it expands the more heat it gives up. In a presurized bottle there is liquid and gas depending upon pressure and temp. This can get deep but this is the basic principles that modern air conditioning use. At 80F in an enclosed bottle the pressure would be 969psia. There is a fill point to leave room for expansion so as not to blow the safety.

You make a good point however co2 does not have a liquid state, hence why it can be so cold and not turn to liquid. It only comes in the form of dry ice, which it has to be lowered to a certain temp before it changes. Any warmer than that temp it just changes back into a gas. It is this property of co2 that makes injecting it into water so difficult. When it's diffused, it comes out in tiny micro bubbles and dissolves into the water. I'm not quite sure how they make the liquid co2 but I'm sure most of it is water with dissolved co2 in it.

The liquid form of Carbon that we dose is not actually CO2, but liquid organic Carbon if memory serves. Not the same thing. When you dose via yeast production or with pressurized you are dosing the gas Carbon dioxide. The liquid Carbon is a different animal entirely, but can be utilized by plants as well. Plants are such versatile things.

This:

The liquid form of Carbon that we dose is not actually CO2, but liquid organic Carbon if memory serves.

is probably not technically correct, in that "organic" means the carbon containing molecule came from living sources and I believe the the synthesis process for all these liquid carbon products is completely inorganic and lab based (but I could be wrong, since the processes are trade secrets.)

The liquid carbons (Seachem Flourish Excel, EasyCarbo, etc.) are polycycloglutaracetal, which are polymerized isomers of glutaraldehydes but the actual isomers are usually in some stage of various patent processes.

But all this is beside the point as it was just that LL just came late to the discussion and didn't know (I think) that it was, literally, "liquified carbon dioxide" (or whatever the heck it does when it gets cold) that was actually being discussed. I believe this gas can indeed be coaxed in to a liquid state once you get above 5 atmospheres of pressure but I don't know the practical aspects of the pressures, temperatures and gas/liquid/solid states typically used by researchers and commercial users.

Grayscale, are the tank pressures we use up in the range of 5 standard atmospheres? I had thought I remembered someone a few years back saying that some of the CO2 is in a liquid state and can even be heard sloshing around inside the typical cylinder.

~~waterdrop~~

 

[GrayScale]

It's kind of funny. I was watching a show on the discovery channel just the other day about co2. Co2 itself does not have a liquid state no matter the pressure but I'm sure when cold enough and put under high pressure, the excess carbon breaks off and forms the liquid. I'm not quite sure of the pressure inside the cylinders in terms of atmosphere.

 

[waterdrop]

No, this has got to just be the show assuming you are closer to atmospheric pressure. You can see the phase diagram clearly showing the area of temperatures and pressures within which CO2 is a liquid on the wikipedia CO2 page. WD