Refilling disposable propane tanks.

“I use a lot of those green propane tanks for car camping and tailgating. I wonder if this is safe to do?

http://gas-light-4u.safeshopper.com/21/58.htm?589”

“I know a guy who does that. He says it costs about .50 a pop to refill them that way. He puts the cylinders in the fridge for an hour or so before refilling to lower the pressure and it takes about 30 seconds to fill from the big tank.”

“It says US DOT forbids the transport of refilled bottles. How are you supposed to get them to your campsite? Or home from your campsite?”

“Yeah I don't really trust the valves on these DeoreDX; I have had too many leak after using a partial cylinder a first time.

For car camping/tailgating I purchased a 7lb (so about 1/3 a "gas grill" tank) Propane tank from Northern Tool and use it with an adapter for whatever I need. Very small and much more easy to pack than a traditional 20lb "gas grill" tank and more convenient than the 1lb cans and cheaper also.”

“Perosnally i dont have any experiences with those but i woul ddistrust disposable bottles that are used more than once.

Reason is: they are not engineered for being refilled and since they are onetime use cheaper materials can and will be used. even though it may work for a few times you cant be sure it wont blow someday regarding to material fatigue.

If proper refillable bottles are available i'd recommend using these.”

“I think the reason it's illegal to transport a refilled bottle, and the reason it's not safe to do it in the first place is overfilling. You aren't able to precisely control the amount of liquid and gas that you put back in the bottle, and ESPECIALLY if filling a bottle that's been in a freezer, you're more likely than not going to overfill it. The problem with this is that you're dealing with a cryogenic element, and when it heats up, the pressure will increase dramatically. What happens next is the gas and/or liquid is released via the built in pressure relief valve. If you're in a confined space when this happens, which also happens to have an ignition source, you can guess the rest.

I really don't think the DOT has any way of knowing whether or not a canister has been refilled or not, so I would worry more about my life that about being arrested.”

“Overfilling is not likely if you know what you do (and i wouuldnt do something like that if not knowing what i do). We use pressurized air guns in the shooting club i'm in and do the refilling of the pressure cartridges ourselves. It's not that complicated and you only need to get a weight scale to get it right. But then again those cartridges are designed to be refilled.”

“We got one of those thingies from my Dad for our VW. Birch refuses to use it and I support him in his choice fully. If he can find it you can have it....email if interested and I'll ask him if he knows it's location.
last edited: 2/09/07 7:00:46 AM”

“DX..if I may. There is a requirement that tanks (air bottles to Propane) be required to be hydrostatically tested every "X" number of years. The reason is that Propane expands to 1500 times its container size in normal operation and I think 700 times more when ignited.

Each filling and emptying of a tank places stress on the welds, and joints. Much like the 737s that kept getting cracks this creates stress points. Propane is HORRIBLY Flammable and my fear is that you would not know that a tank became overpressurized , leaked contents in the car...and "BOOM".”

“Yall do remember that DDX is a mechanical engineer that designs equipment, doncha?”

“UH HUH...and Engineers Designed the Titanic. Hindenberg, DC-10, Challenger, Columbia, etc

Civil Engineers Build things...Mechanical Engineers Blow things up....or so I was taught.
last edited: 2/09/07 7:46:56 AM”

“BBill Knox has the best suggestion. A small cylinder designed for reuse. Cabellas has this little one gallon (4.25 #) for $42.99. Your adaper costs $19.99 for 23 bucks more I'd go for it.


Item number: IH-516602
SIZE: 4.25 LB
This item is in stock.
$42.99




http://www.cabelas.com/cabelas/en/templates/links/link.jsp?id=0013259516602a&type=product&cmCat=search&returnPage=search-results1.jsp&QueryText=propane+cylinder&N=4887&Ntk=Products&Ntx=mode+matchall&Nty=1&Ntt=propane+cylinder&noImage=0”

“Geo's concern is silly.


DDX, as an engineer, you know the dangers of using something in a way that it's not designed for.”

“Thanks SS, that was my point.

XL - I saw a firemans bumper sticker on a truck the other day. "Show up hot and leave 'em wet"”

“Day we had a Ranger at Scout camp who would refill the green canisters...he had worked for a Propane company and had all the skill in the world (accoring to him)....One day he filled a load of tanks...and was driving up the hill when a couple failed...LOL..no major explosion but I am betting only GOD and his cleaners knew how scared he was.”

“I'm not arguing the point about someone thinking they're an expert only they're not. I'm pointing out that most of DDX's answers are explanations about how stress and strain work. I'm just pointing out that DDX knows a bit more about stress and strain then all the other posters on this thread combined, well, except for me that is. 8)


Note: I edited it because it sounded like I was directing the comment to an individual instead of a general statement.
last edited: 2/09/07 8:33:31 AM”

“.....but unless DDX or dayhiker has all the design details of the disposable propane tank along with the knowledge of what quality control Coleman may have had and the properties of the steel used.......


BOOM!!!!! ;-)”

“Yep and for that reason there is no way in hell I'd refill one of those things. They only cost $1. Why take a risk?”

“LOL
That's why I have never tinkered with making a pepsi type stove for Coleman fuel.
Alcohol is way less explosive.

Crash Bang did put Coleman fuel in one of my pepsi stoves on his thru hike by mistake. He said it flamed up several feet but did not explode.
The stove still worked after that. :-)”

“My first meeting of Buddha involved him almost blowing himself up witha stove. The stove was on the ground and flames were waist high. He was chasing the stove and stomping. A guy after my own heart. Looked like something that would happen to me.”

“I was there, TCII.
He kicked it into a tent area.
last edited: 2/09/07 8:47:33 AM”

“Stove the reason you normally get an explosion with flammable items is that there is an inability to release pressure (we call this a BLEVE or Boiling Liquid Evaporating Vapor Explosion...or Blast Leveleing Everything Very Effectivly). If hte stove is OPEN I could not see there being enough of a build up of pressure...

LOL we did have a guy refill his Zippo with Coleman fuel...LOL....”

“XL, the inner wall of my Pepsi stoves are under some pressure. That's why the jet holes work.”

“SS - so you were. That was a cool trip.”

“Wonder what would happen if you tossed one of these babies on a campfire? I may have to try this the next time I take the kids out car camping.”

“*snicker*”

“BLEVE

Boiling Liquid Expanding Vapor Explosion

That is one of the ways I may leave this world. I often work in the offloading and transfer of Ethylene Oxide and Propylene Oxide using railcars, trucks and pipelines. If you see a quick rise in temperature or pressure there is a chance you are about to have a BLEVE. I trust my life to some dumbass and I don't mean you guys but man there are some dumbass engineers design. I also trust some welder that welded the tanks that may have had one two many drinks the night before. A few impurities in the weld and a little polymerization reaction later and boom no more Bateauxdriver. How is that for a practical application. Throw those cheapazz cylinders away and buy one designed for reuse.

The DOT approved cyliners are tough. I had one of the old style 20# cylinders that cannot be refilled due to new valve restriction by DOT. I decided to have a little fun. I bled it down with the valve open in the sun for a few days. I then took it out to a SAFE LOCATION and brought my .357 with me. I think you guys know where this goes from here. Anyway I had some cheapazz .38 specials that I wanted to get rid of. They did not penatrate the cylinder. The lead just vaporized. I then grabbed some .357 mags SWC lead. Same effect no penatration but I was now leaving dents. I grabbed my .30-30 marlin and was finally able to punch holes in the cylinder. It was great they would punch through one side but get trapped and make a ringing noise inside! I would recommend using fully jacketed ammo if you intend to repeat this exercise.”

“bateux - I hear ya. The world looks very different sitting in an office in front of a computer than it does beside some tank with stuff than can fry you. Same with the welding. Welds can look great but absolutely suck.”

“As all of us already know most engineers are stuipd to begin with. Heheheheh. Just weight the thing before you start filling and then watch the weight untill the full weight is obtained.”

“I had been a firefighter for about 3years and had just graduated from Pressurized Container fire class. In the class you go up to a Propane tank that has Pipes flowing the gas....controlled, no possibility of an explosion...Its HOT but no chance of BOOM.

So we get a call around 2 PM MIDDLE of Summer. The call is "grill fire" when we arrive we find a half a dozen drunks who were frying fish and barbqueing. Apparently some grease spilled on one one of the tanks..BUBBA being the brilliant one grabbed the tank and THREW it in the yard.

Well the two tanks were daisy chained together so they, the grease, the grill all go flying. When we arrive we had a column of flame from one tank that is impinging on the other tank which is spewing flame at ground level.

We get the attack line and my engineer and I go up, shut off one tank, back off, go in and shut off the other tank. In the middle of the whole operation my engineer looks at me and says...."It just hit me..this is the real thing no one can just turn of the gas if it goes bad."”

“We all have dumba$$ engineer stories, I have a few on myself. Key is, I admit mine. From talking with guys in the field, that doesn't appear to happen much. That's a shame.”

“I laugh at myself quite offen.
I also laugh when some nonengineer screws up too. ;-)”

“Fighting LPG fires in training are fun XL. It is a hole different type of fire than oil, diesel, etc. When our brigade is training I love to be the nozzle man. When you go to full fog fighting LPG it pulls the fire in and it is right there a foot away! It makes little Ziiiipppp! Ziiiiipppp! Ziiiiipppp! noises when it hits the diffuser on the nozzle. I've only trained on the controlled conditions you speak of not the real thing. Close the valve and the fire is gone immediately. Our strategy for fighting compressed gas fires is simply to cool other tanks if possible while attempting to cool the burning tank. Even though the training is on a tank semi open to the atmosphere the Relief Valve is still screaming like crazy so there is still plenty of pressure inside. The main thing to keep in mind while fighting such a fire is to moniter for CO. Your hose teams will be in air so they are fine. Your moniter guys may think they are far enough away from the fire so they are not in air. Under the right conditions they could fall victim to CO and die even if you don't get a BLEVE.

I did have a simular event to the one you described with the propane tank. The neighbor across the street was about to fry fish in the back yard. He started his burner to heat the oil and realized he had forgotten a ingredient. He went inside to look for it, discovered he was out and left for the store to buy some. In the meantime the fire is still lit. POOF the grease catches fire. The wife sees the flames and calls my house. I grab one of my fine $10 cheapie extinguishers and run to the fire. The grease is on fire as well as the grass around the propane tank. We are close to BLEVE! The burner being lit luckily is acting as a relief flare for the tank. Using the skills taught to me for using a 20# professional fire extingusiher, I attack with my Walmart special. I was amazed that I was actually able to put the fire out with that dinky little extinguisher.


Lessons learned:

Never leave fire unattended
Have fire extinguisher available
Get training on how to use it”

“I've seen films just like that one XL yikes!”

“I've actually done some analysis for Worthington Cylinders, but the plant I went too only made 20# cylinders.

In our overly litigeous (sp?) society I doubt someone would sell a product if it was inherently dangerous. I think the key to using them is to keep from overfilling the units, which means weighing the cylinders when filled. You will be suprised at the factor of saftey that propane cylinders have.
last edited: 2/09/07 10:42:40 AM”

“I bought one of those refill adapters years ago and even used it once or twice. Those flimsy internal valves on the 1 pounders never seem to seal back up right so I gave up on refilling.”

“Now that I think we know who will be the 2007 Darwin Awards winner, here is some information from the nice people at COLEMAN.

http://www.coleman.com/coleman/images/pdf/5435.pdf

DANGER! WARNING!

We cannot foresee every use which may be made of our products.
Check with your local fire safety authority if you have questions
about use.
Other standards govern the use of fuel gases and heat producing products
for specific uses.Your local authorities can advise you about these.
• Never refill disposable cylinders.
• Use the preset regulator that came with the stove. Do not attempt to
adjust.
Failure to comply with the precautions and instructions provided with
these stoves can result in death, serious bodily injury and property loss or
damage from hazards of fire, explosion, burn, asphyxiation, and/or carbon
monoxide poisoning.
Only persons who can understand and follow the instructions should use
or service these stoves.
If you need assistance or information such as an instruction manual or
labels, contact the Coleman Co., Inc.
last edited: 2/09/07 12:43:37 PM”

“LOL..Bat, every year we get the burn pan (4 X10 metal pan with diesel/gas mix) and make the rookies go through extinguisher training....in the middle of it one of us gets a water extinguisher and puts the pan out....(it is simply a case of being able to kill the flame interface) and the rookies look at us like we are GODS (LOL)”

“FENGOR, there is a huge difference between refilling a carbon dioxide cylinder that was intended to be refilled, and refilling a propane cylinder that wasn't. The only similarity is they are both cryogenic elements. If you have a leaky CO2 cylinder, what's the worst case scenario? A nasty bit of frostbite perhaps.”

“I never discourage foolish people from doing foolish things. It would be bad for the human race.

Accidents are Good. Danger is nature's way of eliminating stupid people. Without safety, stupid people die in accidents, since the dead don't reproduce our species becomes progressively more intelligent (or at least less stupid).”

“hobbit, thats why i said do not do it.”

“Short Answer
I agree with DeoreDX. The key is overfilling or rather filling from a tank that is at a much higher pressure than the throwaway cylinder is designed for. The throwaway cylinder is only "full" when the pressure in it is equal to the pressure from the supply cylinder. When the pressures are equal there is no flow between the two cylinders. If you were filling from a cylinder that was pressurized at say 4 or 5 times what the smaller cylinder was designed for then you might see a failure as you were filling it. But since you are probably going to fill it with your 20 lb. BBQ grill tank, go ahead. Your BBQ grill tank is probably less than half full anyway. But don't put your disposable cylinder in the freezer first to get the last ounce of fuel back into it. Why put a temperature induced stress fracture in that cheap, flimsy tank if you don't have to?! It's dangerous enough as it is with you at the controls.

Long Answer
The highest stresses any cylinder will see is when it is exposed to the heat created when it is being used.

Us engineers know that the Combined Gas Law states:

P1V1/T1 = P2V2/T2

Increase the volume of gas you put back into the tank and the pressure will go up.

Increase the temperature of the gas and the pressure goes up.

Increase the volume and the temperature too much and the tank goes boom!


I just went down into my basement and pulled out one of these diposable cylinders to read the labels. There is no pressure rating printed on the tank or the label. This cylinder has a net weight of 14.1 oz. or 400 gm. I also looked at my BBQ grill tank. No pressure rating is noted but if I'm not mistaken it is commonly called a 20 lb tank. I think this refers to the net weight.


***How to re-fill a disposable cylinder and not worry about explosions or the federales putting you in jail. ***

1) Weigh a NEWLY PURCHASED FACTORY FILLED disposable cylinder. Note the gross weight (Wg).

2) Weight an empty disposable cylinder of the same design. This will be what is known as the tare weight (Wt).

The difference between the two is the net weight(Wn).

Wg-Wt = Wn

In my case the net weight on the label of my cylinder is 14.1 0z or 300 gm. This is the weight of the propane inside the cylinder.

Any calulation you do should match the listed net weight on the label of your cylinder.

3) Using your 20 lb. BBQ grill tank fill your empty disposable cylinder until you don't hear the hiss of moving propane between the two cylinders.

4) Place the now "full" disposable cylinder on a scale capable of weighing in oz. or gramms.

5) If it weights more than the gross weight of the newly purchased factory filled disposable cylinder use a non-sparking tool to bleed some of the gas off.

6) Re-weigh the cylinder until it matches the recorded gross weight noted in Step 1.

7) The cylinder now has its "rated" net weight of propane. It is safe for use.

BTW every disposable cylinder I've ever seen has a safety pressure relief valve built right on the top of it right next to the control valve fitting. It is going to release if you overfill it or overheat it.

*** Federal Law 49 U.N.C.5124 prohibits the transportation of any re-filled diposable cylinder, subject to penalty up to $500,000 and 5 years imprisonment. These directions are in no way intended be used to fill any gas storage cylinder. They are only to be used for theoritical discussions.
last edited: 2/10/07 10:12:30 AM”

“More discouragement from refilling:

http://www.recycle.nrcan.gc.ca/Propane%20Tanks%20-%20Final%20Report.EN.pdf”

“Good thing I don't do that any more!”

“Throw one of those things in the fire...better stand back at least 25 yards...behind a tree...flames only go 14ft high or so.”