Can a propane tank be repurposed?

[W8BYA]

I will admit to my total ignorance when it comes to pressurized storage containers and could use some help. I have had no luck trying to find answers to most of my questions on the net.

Here is an idea I have had for years and wondering if it can be safely pulled off. The goal would be to have a pressurized utility sprayer that I can carry around with me for spraying roundup etc. I am tired of pumping my 2-3 gallon sprayer every several minutes. I have a 5-gallon backpack model but once full I have a hard time getting it on/off by myself and it hurts my lower back as I walk around my 6 acres. I like the idea of a smaller, pressurized, hand held 2-3 gallon sprayer. I know they make battery powered units but I like to experiment & was wondering if an empty propane tank be repurposed (refilled with air) to provide the 10 PSI that I need? I do not think the high pressure paint-ball tanks is what I want as they are thousands of PSI and expensive.

I have long wanted to take an empty (small torch sized) 1-pound propane tank and refill it with air via my shop air compressor and try out my idea. I would attach a regulator to knock down the high pressure air down to ~10 PSI.

My 1st & most important question is what PSI can these small 1-pound propane tanks hold safely? The last thing I would want is to set my shop compressor too high & have a catastrophic failure due to too much pressure while refilling it. The next question would be where can I get a low-pressure regulator with a gauge so I can dial in the PSI into my 2-3 gallon sprayer.

 

[fishdrivel]

Not touching this with a 10 foot pole.
Compressed gas containers kill a lot of people!

 

[W8BYA]

Not touching this with a 10 foot pole.
Compressed gas containers kill a lot of people!

So everyone who refills their propane tanks with a larger propane tank is at a high risk of killing themselves?

 

[3gunr]

Buy a 15 or 25 gal spot sprayer, put it on your tractor in one of several places handy plug in to battery and spray all you want without the trouble you are looking at with your method.

 

[W8BYA]

Buy a 15 or 25 gal spot sprayer, put it on your tractor in one of several places handy plug in to battery and spray all you want without the trouble you are looking at with your method.

Appreciate the idea......would be fine but this is not for spraying hundreds of feet of fence lines or tree lines etc.....way too much close in spraying that must be done on foot.

 

[LouNY]

Hundreds of U-tube videos of converting propane tanks to air tanks.
If I was going to do one I would use an 80psi relief valve.

 

[LouNY]

According to the national standards publication NFPA58, a propane tank with 20 pounds (5 Gal) of gas at 70°F would have a pressure of 145 psi; at 90°F

 

[duffer]

There is a reason why propane tanks have an expiration date. Much of the reason is the stress that the tank gets during the 10 yr life cycle. Pressurized, depressurized, rinse & repeat for 10 yrs. Much like an airplane that needs to be re-fit on a regular basis. Add to that, the fact that the vast majority of propane tanks sit outside in the weather, and they're made of steel that rusts, adds to the instability of the tank over time.

Human nature is to take things to it's limits. If you pressurize the tank to 5-10 lbs you won't be able to spray your herbicide for very long without repressuring the tank. Tempation will kick in and you'll up the pressure to have a longer "charge". That's when you'll likely get into trouble.

Do what you want, but I'd heed the advice of most of the other posters to find a different solution than a propane tank, and stay out of the E.R.

 

[W8BYA]

Hundreds of U-tube videos of converting propane tanks to air tanks.
If I was going to do one I would use an 80psi relief valve.

Can you reference a couple of them where the person actually knew what they were doing and knew the safety limits of the tank etc? I do not mean for that to come out wrong or disrespectful because I appreciate your input but just because I see someone doing something on YT does not automatically mean it is safe to do.

 

[W8BYA]

According to the national standards publication NFPA58, a propane tank with 20 pounds (5 Gal) of gas at 70°F would have a pressure of 145 psi; at 90°F

Awesome that you referenced a standard. Thank you. Do you by chance know the PSI for a standard 1-pound tank?