Can a propane tank be repurposed?

[LouNY]

I would expect that it is very similar as they are both filled with liquid propane and then we draw the vapors off with the valve at the top.
A few years ago it was common to refill the small tanks from a 20#, you had to invert the 20# to get liquid to transfer to the little tank.
Otherwise it had very little volume.

 

[W8BYA]

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.

Appreciate that guidance. But I think we are talking about two different propane tanks. I am wanting to learn more about the small 1-pound propane torch tanks.

Also, the 10-15 PSI is the intended pressure inside my sprayer bottle. I would imagine the air-filled propane tank would be filled to 40-80 PSI (not sure).

And you bring up a great point about a 10 year life cycle. Is that for the small 1-pound tanks as well? If so I have no problem buying a new tank, emptying it, filling it with air and using it for 5-6 years then replacing it.

Most importantly I am on a fact finding mission here. I am asking because I do not know and if it sounds like a gray area I will simply stay away from it and get a battery powered unit. It is just you see thousands of VERY high pressure paint-ball tanks filled every day....I just wonder if the 1-pound propane tank can be refilled just like them.

That also just made me wonder if I could use a paint-ball tank that is very high pressure and regulate it down to 10 PSI and then use it?

 

[W8BYA]

I would expect that it is very similar as they are both filled with liquid propane and then we draw the vapors off with the valve at the top.
A few years ago it was common to refill the small tanks from a 20#, you had to invert the 20# to get liquid to transfer to the little tank.
Otherwise it had very little volume.

Roger that ! I have filled several 1-pound tanks using a 20# tank several times......exactly as you say, just make sure it is inverted so you fill it with liquid. Never had any problems but since I do not have any gauges on the setup I was at a loss at what the internal PSI was. TU agn.

 

[Rustyiron]

1 gallon pump up sprayer is about 10 bucks at HD. Much lighter and takes very little pumping.
I've also added a valve stem to this type of tank before if you absolutely don't want to pump. Just be prepared to walk back to the shop to refill it.

 

[Doughknob]

So OP i think you’d find even if you did what you initially posted, that ‘volume’ in the torch tank WAAAAY to little for what you need in 2 gallon sprayer.

 

[Eagle1]

All this worry yet how many put 120 PSI in a 50 year old portable air tank? Who changes their air compressor tank every 10 years? The stresses are same, just air is not flammable.

 

[Smokeydog]

With so many kinds of readily available sprayers to purchase why shake hands with danger? Large or small propane cylinders are not coated inside to resist corrosion.

Paint ball and SCUBA tanks are only meant for dry air.

There are some quart to several gallons spray containers made to be pressurized using a air compressor and are vary expensive.

It’s good that you ask a question. Hopefully you can understand why it’s not a good idea.

 

[lpakiz]

To give you a simple answer to a simple question.....
Propane pressure is linear to its temperature. Doesn't matter if in a 1# camping bottle or in the tank of a 8,000 gallon railroad car, or any size in between, including the 20 pound tank on your grill outside.

It matters not if the bottle, tank or tanker has 1# , 3 gallons, or 1,000 pounds or 8000 gallons. Temperature decides pressure of the liquid (and gas) inside that container. I didn't Google it for exactness, but 250 PSI is easily possible in a grill tank, in the sun, on your deck.
That said, you better know what you are doing before you introduce regulated pressure into another vessel not designed (or SAFE) for the resultant pressure. There are safeguards built in to all propane vessels for a reason. 20# and larger tanks have a stamp on the side indicating max working pressure.
BTW, I use a 100# propane cylinder, hung upside down from my shop ceiling for my air compressor receiver. I've had it for 40 years or so. My compressor is set to shut off at 150 PSI. Actually, I think it's heavier metal than the tanks of commercially built air compressors. I also use 20 pounders for portable air tanks. One just needs to get the right plumbing to make this work.

 

[JJT]

I converted a 20 pound propane tank to an air tank, 20+ years later it still smells like propane. I don't think the mercaptan smell ever goes away.

 

[grsthegreat]

Think backpack sprayer. Nice easy to use handle to pump while its on your back. ive used them for years. Very easy to use and walk thru brush. All weight on back, not arms.


edit: sorrt..i reread your post, and see you tried backpack sprayer. Problem is even a pressurized unit will need to be carried around, and holding them in hand sucks.