Airbrushing with CO2 - setups

[chops1sc]

Anyone here use CO2 tanks to airbrush? I recently picked up a tank on sale but I would like to see some setups if possible.

TIA!

[Jetblast]

Don't have an existing set up, but have in the past & familiar with it;

Make sure the tank you have is for gaseous CO2 as some have a dip tube & can only supply liquid CO2 (Not sure about Canada, but in Europe gaseous is in a black bottle, liquid in black with a white vertical stripe),

All you need is a two stage regulator (welding supply shop is best bet) adapter & hose. A CO2 tanks output pressure can easily overpower standard airbrushing equipment, so try to get a regulator that's limited on the output to suit - if this isn't something that's in stock at a welding supply shop, they should be able to order specifically for little additional cost. Not sure about the adaptor size required over your side of the pond.

Pros -

Easy to set up, silent & bone dry operation.

Cons - (some dangerous!!)

Tanks are pressure tested, inspected & date stamped during the refill process, if the tank date has expired you will not be able to exchange for a fresh tank without inspection (tank inspection may costs more than an outright tank purchase/rent)

A standard two stage regulator will not accurately indicate what CO2 remains in the tank & will show more or less full until the tank is well run down & then suddenly appear to show next to nothing (that happens when the liquefied CO2 is gone & all that's left is gaseous CO2). The easiest way to keep an eye on levels is to weight the tank & subtract the empty tank weight...

You need to be seriously careful if using CO2 in a domestic or enclosed environment, it's not poisonous but is an asphyxiant & odourless, so a leak has the potential of being catastrophic!

A fully charged tank has a huge amount of potential energy, so should be carefully transported & securely chained / blocked / bolted into position when in situ.

[chops1sc]

Thank you for this information! Hopefully I can get it setup soon. All I need is a section of hose and to get it secured in place. The regulator I have shows the output in cubic feet (or meters) per hour iirc. I have a low pressure gage that I currently use on my compressor. I'll have to attach it in-line so I can set my pressure right.

I'll post a pic once everything is setup!

[chops1sc]

So I was able to get everything setup. I still have to find a home for the tank but it’s working. I haven’t actually painted anything yet but I plan on doing some painting this weekend.

[Fridgy]

As someone who works with high pressure gases everyday (refrigerant, nitrogen and CO2)
All i would say is be very careful with using CO2 as a propellent.

For the cost of setting up to use CO2 you could have purchased a compressor to use

IMHO i would stay away from both CO2 and nitrogen unless you have been throughly trained in their use, handling and storage as both these gases will kill you quite quickly if they leak and the concentration of them in the room is high enough

Just my 2 cents worth

[digger303]

Missing a hose clamp, but I'm betting you know that. In the interests of safety if you were to get a squirt bottle filled with a lot of dish washing deteregent and water and squirt it around those fittings every so often. Then leaks could be detected and probably just me, but I would have used reinforced air hose between the cylinder and regulator.....me being cautious....the hose as it ages will be less inclined to split, kink or crack.

[AlexBB]

Please be very careful using CO2...

It’s not just a leak you need to consider.

An airbrush will use about 25 Lts/min at normal atmospheric pressure, this means you will be displacing the same volume of air in the room with CO2. This will dilute the O2 concentration below 20.9%

CO2 is an asphyiant and will kill you in confined spaces.

Unless you have a very well ventilated room you could be in danger.

[digger303]

that would be a worry....if you have a good spray booth venting to the outside it might be less of a worry.

As another thought, could a divers cylinder be used as that is compressed air.

[chops1sc]

I’ve read about using compressed air but unless you can find a good tank at a steal, you’re better off getting a nice ab compressor lol. That’s the only reason I went with CO2. I’ve only invested $70usd so far in my setup.

I don’t have a paint booth yet but I do run a window fan when I’m painting. And I always turn the tank off when I’m not using it.

[AlexBB]

If you Google Safe Levels of CO2 you find lots of information. the following is a guide;

What are safe levels of CO and CO2 in rooms?
CO2

250-350ppm Normal background concentration in outdoor ambient air
350-1,000ppm Concentrations typical of occupied indoor spaces with good air exchange
1,000-2,000ppm Complaints of drowsiness and poor air.
2,000-5,000 ppm Headaches, sleepiness and stagnant, stale, stuffy air. Poor concentration, loss of attention, increased heart rate and slight nausea may also be present.
5,000 Workplace exposure limit (as 8-hour TWA) in most jurisdictions.
>40,000 ppm Exposure may lead to serious oxygen deprivation resulting in permanent brain damage, coma, even death.

For short duration enclosed work (Confined Space) alarms we use a setting of 19% O2 on our personal Oxy Alarms, with a secondary alarm at 17%.

Oxygen dilution ratios in a room are complex and need to be assessed, this includes air coming in and going out and the rate at which CO2 is entering....

There are a number of conversion factors you would need to use to convert Lts/Min of CO2 to used KG and determine the rate at which it is entering the room.

If we said it was a 3m x 3m x 2.3m room and you are using 25lts/Min for 10 mins.
Then
Oxygen depletion calculation:
Final O2 concentration = 20.9 - k*Vn/Vr
where Vn = litres spilled (kg for CO2)
Vr = room volume in cubic metres
k = 18 for He, 14 for N and 11 for CO2

1 Sm3 of CO2 = 1.873 Kg
Thus 250Lts = 0.469 Kg

= 20.9 - 11 x 0.468/20.7

Thus 10 mins use drop the O2 concentration to 20.65% (with no air exchange)

About 40 Minutes use will see the O2 Concentration drop below 20%

I have to be honest and say at work we would not allow the use of CO2 for an application like this without defined and controlled forced ventilation. Compressed air would be used.

I and I guess anyone else who uses CO2 in industry would say spend a $100 on a compressor and be safe..

[digger303]

So how are you going with that C02 setup ?

[chops1sc]

Pretty well! I did get some nylon reinforced tubing and got both ends clamped. I love how quiet it is. I haven’t done any major spraying yet (full tank, car body, etc.) but I haven’t noticed any cons so far!

[digger303]

[chops1sc]

Just a quick update for y’all. I recently ran out of my first tank of CO2! I don’t know exactly how much I have painted but I know now that I won’t have to worry about having to get but about 2 tanks a year. I will be filling up again after we get back from vacation!

[digger303]

Just a quick update for y’all. I recently ran out of my first tank of CO2! I don’t know exactly how much I have painted but I know now that I won’t have to worry about having to get but about 2 tanks a year. I will be filling up again after we get back from vacation!