Refill Disposable Propane Tank from a Standard BBQ Cylinder

Picture of Refill Disposable Propane Tank from a Standard BBQ Cylinder
I refill my littles 1 pound propane bottles from a big one. I'm going to show you how...
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Step 1: Safety First & Disclaimer

Disclaimer : Whenever there is propane there is risk. If you decide to refill your propane tanks yourself, you have to understand that you do it at your own risk. These cylinders aren't DOT approved for refilling. This means that you can't take your cylinders to the local propane-equipped service station and have them refilled. That's against the law. And refilled cylinders can't be sold commercially. And commercial operators can't transport refilled cylinders across state lines. There are all sorts of limitations and potential liabilities associated with refilling these cylinders. It's perfectly legal to refill them for personal use, however.

There is some safety precautions that you have to take when refilling your disposable propane cylinders and you will need to handle it properly and observe all the best-practice safety protocols.

#1 Always do the refill process outside.

#2 Never smoke during the entire process.

#3 Be sure there is no open flame in the area.

#4 Wear safety glasses and protection gloves for added safety.

Again, I am not responsible for any accident that can happen when you refill your own disposable propane tank.

Step 2: What you will need

Picture of What you will need
First you will need a propane tank refill adapter from Mr.Heater also called Mac Coupler. They are easy available on the Internet on Ebay or on the Cabela's Web Site.

Link for Ebay: http://shop.ebay.com/?_from=R40&_trksid=p3907.m38.l1313&_nkw=propane+refill&_sacat=See-All-Categories

Link For Cabela's : http://www.cabelas.com/prod-1/0013259512325a.shtml

You will also need a standard propane tank at least 50% full, empty disposable cylinder, a kitchen scale an a notepad to keep track of the weight of your cylinders. For added safety I also recommend safety glasses and gloves (not show on the picture)

Step 3: Collect Empty Disposable Cylinders

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I collect empty cylinders form the campgrounds I visit. Most of the peoples trow them away in the recycling basket I collect them. I also collect the plastic caps because I always store my cylinder whith them to protect the tread and the Shreader valve. Look for bottles that have not dents or rust and the ones that are not to old (the production date is stamped on the bottles)

There are 2 types of disposables tootles :

Type #1 With plastic Base (Coleman Type)

Type #2 With metal Base

I have a preference for type #2 because the metal base wont go off the bottle like the plastic cap but both type work. They have different empty weight and we gone a check this in step #6

Step 4: Chill Empty Cylinder

Picture of Chill Empty Cylinder
Chill Empty Cylinder for 1 hour for best result. This operation lower the pressure in the cylinder. To refill the cylinder, you have to create a pressure differential between the giver and receiver tank.

Step 5: Warm 20 pounds Cylinder

Picture of Warm 20 pounds Cylinder
Put your BBQ cylinder in warm water (not hot) for about 1/2 hour. This operation increase the pressure in the giver tank. If your bottle is under the sun a warm and sunny day, just skip this step, you don't need to do that.

Step 6: Weight Empty Cylinders

Picture of Weight Empty Cylinders
Weight the empty cylinders.
I give you my result after I weighted about 24 tanks :

Type #1 With plastic Base (Coleman Type)
Average empty weight : 384g
This mean a 100% full tank will weight 849g (384g tare weight + 465g of propane)

Type #2 With metal Base
Average empty weight : 417g
This mean a 100% full tank will weight 882g (417g tare weight + 465g of propane)

Step 7: Do the refill process

Picture of Do the refill process
To do the refill process, do those steps :

#1 Plug the refill adapter on the big tank FIRST

#2 Screw the little thank on the adapter.

#3 Flip the tank over like on the picture.

#4 Open the valve. The instruction say to let in open for 1 minute but you will hear the flow of propane stop after 30-40 seconds. When the sound of the flow stop, close the valve.

#5 Flip over again the big tank and remove the little one of the adapter. Some propane will escape from the adapter during this process.

Repeat the operation until you have filled all of your tanks.

Step 8: Weight Refilled cylinder

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Weight the cylinder to check the results:

On the first image you see a coleman type tank filled at 89% (797g total weight)
797g (total weight) - 384g (empty) = 413g Propane Weight
413g / 465g = .888 or 89% full.

On the second image you see metal base type tank filled at 87% (822g total weight)
822g (total weight) - 417g (empty) = 405g Propane Weight
405g / 465g = .870 or 87% full.

I never refilled a cylinder more than 100% but if you do it, I suggest to put it on a gaz burning appliance so the extra gas will escape to the safe weight.

Step 9: Check for leaks and store refilled cylinders

Picture of Check for leaks and store refilled cylinders
Once you've refilled a cylinder, you should place some soapy water on both valves (the pressure relief valve and the regular valve you connect to your appliance) and check for bubbles. Bubbles = leaks. A leak never happened to me but it's better not to take chance.

I store my refilled cylinders outside just for precautions, in case of a leak.

I also put a protective cap like on the picture to protect the threads of the boottle.

Good luck refilling.
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mgordon82 years ago
This is a very unsafe Idea. Propane cylinders have vapor and liquid propane in them. The liquid is at the bottom and if you use this method, you will more than likely be putting only liquid into the "refill" cylinders. Cylinders must have vapor in them for safety. Please be smart and stop doing this.
All propane cylinders have liquid propane into them, the gas is there as a result. It's actually quite hard to accidentally fill a propane bottle with just liquid, you'll almost always end up with gas in there because the pressure differential will drop off and stop forcing liquid in, and gas will evaporate to fill the empty space. So doing it like this is quite safe as long as you don't freeze your skin off.
this is still a bloody stupid idea, these containers are not dot certified for refilling because they don't have the kind of fittings and safety valves that 22 pounders have. the threat of the liquid propane is very real, liquid propane evaporates at a rate faster than liquid nitrogen, this is often expedited by the gas being combustible and downright explosive at the quantities that liquid propane allows.

just to give you an idea there was a house near mine that exploded because the basement filled with propane gas, they didn't find a single piece of the house bigger than a foot in the mile radius that the debris fell. nor did they find any of the remains of the 3 people in the house bigger than the same size. the amount of liquid propane filling a tenth of that container could fill the same basement 20 times over. to add to this you are putting stress on the valves by putting liquid propane through it, it will fail eventually.

Your neighbors house exploded because of a even mixture of Gas and Oxygen allowing rapid combustion. AKA, explosion. All the tanks in question have relief valves. Even the gas comming out of a relief valve is not able to burn until it is a few inches away from the valve. Because it needs to disperse and mix with O2. If the 20# cylinder is filled properly (80%) then thats all you can fill the 1# cylinder to. The 1# is filled with a vapor. The reason you fill it on its side is so that vapor becomes trapped. The 20# has a liquid. You are flipping it upside down so liquid is pushed into the 1#. The pressure required to fill the 1# to 80% is the same as required to fill the 20# to 80% at the same temperature. Of course the tank will not be at 80% once 1# of liquid is gone. It will be 75%. So you chill the 1# tank to compensate.

Long story short. Its just as safe as filling anything else to 100-200PSI. Anyone with an air compressor does that often.

yyyyyyyyep. I'm out. Thanks.

Is it safe to remove a bbq tank from a bbq and move it to another bbq if its not empty?

Of course, Just close the valve.

marc brown1 month ago
Does the BBQ tank have to be upside down?

I can't get more than 100g into my empty Coleman cylinders.

I just had my BBQ tanks filled by U-Haul.
BradS14 months ago

As I read the law, it is not illegal to refill or use refilled disposables on your own property as long as you NEVER transport refilled disposables over ANY public roadway for any reason. However, just because someone manufacturers an adapter does NOT mean it is safe to use. A better resource is www.propane-refill.com

First problem I see with refilling disposables is that when a 20# tank is inverted, you have bypassed the internal safety devices built into it and ignored the manufacturer's instructions to always keep the tank upright. Another fact here is that the pressure relief valve built into disposable cylinders is calibrated for a specific pressure release and NOT designed to be pulled or pushed on. Next issue is that the disposable tanks are built with a cheap rubber O-ring and are not engineered for prolonged, multiple uses. The final big problem with refilling is that the propane filled into single use cylinders at the factory is DE-humidified to prevent the cylinders from rusting from the inside out! Commercial propane bought retail/wholesale in your 20# BBQ tank is NOT dehumidified and does not need to be because they are designed and certified to be used and refilled that way. Facts are facts... do yourself a favor and be safe- buy refillables at www.propane-refill.com

KenC29 months ago

The usual recommendation is not to fill to more than 85%.

By experimenting with a pickle jar filled with water and a hole in the middle of the cap, I had to tilt it to 74 degrees off the vertical before 15% of the water left the bottle. I used an electronic angle gauge to measure the angle.

Worthington cylinders weigh around 31.7 oz new. I refilled a cylinder to 32 oz. When I fitted a torch and lit it, I found I could tilt it 74 degrees before the flame went from [gas] blue to [liquid] red.

This is another way to test a cylinder to see if it is overfilled. It is a bit surprising how close to level you must be able to bring it [i.e. 16 degrees] for it to be safely filled.

The pickle jar had proportions similar to the Worthington. The results are probably different for different shape cylinder.


BradS111 months ago

Please be very careful when making statements like: 'It's perfectly legal to refill them for personal use, however." While this is technically correct, refilling single-use tanks goes against the National Fire Prevention Assn code as well as flaunting several safety guidelines. Refilled single-use cylinders are also illegal to be transported over a public roadway by anyone except a certified Hazardous Waste Hauler, even without crossing state lines per the DOT. Brand new on the market now is legally refillable camping size tanks so why bother being dangerous?

Rogermana BradS110 months ago

Thank you so much for your technically correct interpretation of the law and everything pertaining to the regulation of life, procedure and safety guidelines pertaining to the safe enjoyment of our lives free from the contamination of any possibility of unsafe practice both in the home, on the highway and at work. Now I tested a camping disposable propane cylinder, and a MAPP Gas, Burnzomatic cylinder last month. I covered them with rags, douced them with petrol and set them on fire from a distance of 20 feet. Each one gently gased off and burned down with out incident, except for a harmless bang at the end when the top came off the thin walled propane cylinder. The last time I heard that Propane was any real danger was when someone parked a large panel van full of it, with explosives, under the World Trade Center. Other than than, I simply have not heard of them being dangerous. Probably they are in some circumstances, but our friend here has it covered.

pcooper21 year ago
In the early 1980s, Cleanweld Turner offered their LP1501 propane refill adapter that worked far, far better than the stubby thing offered by Mr. Heater, shown in this instructable as a "Mac Coupler". It was intended to be used with their LP4585 refillable propane cylinder — the tall, narrow type typically used with propane torches. This cylinder had a hex-nut relief valve that could be operated with a small wrench. Disposable cylinders have a recessed valve stem that can only be operated with needle-nose pliers, or a special valve core tool that can reach deeper than the ones used on automobile valve stems. The main feature of the LP1501 was that it kept the cylinder being refilled upright, with the relief valve topmost, so one could bleed gas off while filling and get a 100% fill each time. The instructions that came with the L4585 cylinder said to weigh it after filling and bleed off gas until the net weight of propane did not exceed 13 oz. For a nominal 1 lb cylinder, that represents an 81.3% fill, leaving some headroom for gas expansion if the cylinder were left in a warm room or car trunk, without having the relief valve open at an inconvenient time.

Cleanweld Products, Inc. sold their Turner division to Cooper Industries in 1984 and the product line was folded into Cooper Tools in Raleigh, North Carolina. Sadly, their refill adapter and refillable propane cylinder disappeared from the market not long after that. I've attached a photo of my Cleanweld Turner refillable cylinder and adapter for your enjoyment, purchased sometime around 1981-1982.
BradS1 pcooper211 months ago

They are available again at www.propane-refill.com

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pcooper2 BradS111 months ago

Thanks for the link. Their proprietary system looks like it's more expensive and complicated than it needs to be, but at least it gives the public a safe option. They probably never saw the original Cleanweld Turner products before coming up with their solution.

pmally6 years ago
you know there's a little shrader valve in the side of most of thoes tanks so you can get the AIR out of the tank when your filling it any propane tank has a bleeder valve, that's how you get the tank full even if you had a propane pump to help fill it up

There shouldn't be any "air" (nitrogen+oxygen+carbon dioxide+water vapor) in the propane cylinder. It should be 99.999% propane and other flammable petroleum gases. If there's air in the cylinder, it needs to be purged before putting the cylinder to use.

J57ltr pmally3 years ago
It's not a bleeder it is a safety vent for DOT regulations.
sconner1 J57ltr3 years ago
Correct. The valve is to vent excess pressure so the tank won't burst.
The valve may have been used to bleed air on the first factory fill.
But as you use the original fill, propane gas exits only. No air enters the tank.
The "air" in the tank is simply leftover Propane gas at a pressure of approx 1 atmosphere.
To vent this gas is wasteful and you run the risk of overfilling the cylinder too.
What happens then? As the temperature rises the pressure valve releases the extra, wasting more gas.
sconner13 years ago
Chilling is unnecessary.
Hook up a full tank (under high pressure) to an empty tank (under less pressure relative to the full one) and open the valve between them and the pressures will equalize. Some of the contents of the full tank are forced into the empty one until the pressures are equal. Close the valve and disconnect. Done.
lime3D sconner13 years ago
The instructions on the adapter specifically say to chill the empty tank.
sconner1 lime3D3 years ago
Thereby lowering the pressure some more allowing a little more to be drawn in from the fill tank.
If one wanted to go overboard they could use a vacuum pump on the empty tank first. But that may cause it to overfill, who knows.

Show us a SINGLE photo of an over pressurized and burst disposable tank.

Because of the possible damage and death, overfilling is just not worth the little bit extra. Be safe, live long, and prosper.
johnsned515 years ago
OK, bottom line. I'm a propane supplier and I honestly hate this idea, but I'm also realistic enough to know that people will still do it, whether I like it or not.

#1 Do not, under any circumstances, a cylinder to 100 %! Propane has a high temperature/volume expansion rate. Too full when cold means it pops off when it goes hydrstatic (liquid full @ high pressure). 85% MAXIMUM!!!
#2 propane expands at a ratio of 1 to 270 when it goes from a liquid to vapor. Stack up 270 of those little cylinders in your trunk behind where your kids ride in the car on a good hot day.
#3 There is a technical explanation as to why you find half full 1# cylinders in the forest, I mean besides the fact they are wasteful litterbug jerks.
It goes like this, If you know the physical properties of propane, you know that propane appliances burn propane vapor. At atmospheric pressure propane is a vapor. At -44 degrees it is a "0" pressure liquid. Pressurize propane in a tank and you can keep it liquid at higher temperatures. Think thermodynamics. Small tanks, small volume, gas cools in cylinder faster, chills gas to -44, no vapor, no burn. No burn, must be out of gas, throw away 1/2 full tank. (yes, I've seen it! Over and over!)
Big tank, big  volume,gas cools slower, doesn't get to -44, burn hotter longer

Better yet, just don't do it. state an federal agencies do'nt write rules to "big Brother" us. They may seem misguided sometimes but they really want us tobe safe

I always think of compressed gasses as the perfect vehicle for a Darwin moment. That I survived adolescence (OK, young adulthood, too - I'm a slow learner. ) was purely due to my good fortune. But passing laws against being stupid is just wasting your time.

You're observations are correct. I've seen 1-pound cylinders develop frost on them when both burners on the camp stove are wide open. As the expanding gas chills the cylinder, the gas pressure drops and the stove heat output starts dropping, although it doesn't quit completely. I like to pick up other folks' discarded "empties" and put them to use on my propane appliances to get every last bit of usable fuel out of them.

The small, disposable cylinders are handy for picnics and camp-outs, but if one wants to do some serious cooking, an 11-pound or 20-pound cylinder is a better choice, since their larger surface area makes them less likely to chill to the point of freezing.
To johnsend51 : why dont you learn how to write. Your negative comment gave me a headache trying to comprehend what you are trying to say.
Here's the dummies version:
Gasses expand with temperature.
If Nit-wit fills a tank's total volume with liquid gas under pressure, there's no room for it to expand.
Tank bursts.

As Nit-wit uses the gas in the cylinder quickly, more liquid evaporates cooling the rest of the liquid because of the same physics air conditioners work on.
The rest of the liquid gets so cold that it won't evaporate any more.
Nit-wit discards half full cylinder.
Half full tank has time to warm up again.
Smart guy picks up half full cylinder.
Litter Bad.
Free Propane Good.
Well, Jcwtexas, it's not johnsned51's fault that you can't read and / or have no scientific education. His post was totally readable to me and is not negative. It's informative.

This is a dangerous thing to do. There is a good reason that these cylinders are not rated for refilling. They are designed for 1 use, but are over spec'd for safety. It's that safety margin that you are playing with.

Have you ever seen the sort of explosion and the devastation that one of these can cause, it can easily kill.

So if you’re going to refill, then having more info is very valuable. It could save your life. So if you do not understand the info passed on here, do not refill any cylinders. Or, rather do, and rid the gene pool of yourself.
I agree with AfricanMystic and johnsned51, I have an adaptor for filling the 1 pounders and I am going to toss it - It is much easier and safer and in the long run probably cheaper to just go and buy the 1 pounders on sale at a discount store!
I don't think this is proper English: His post was totally readable. Legible maybe? or understandable?
Dodge jcwtexas4 years ago
Read it with a Hank Hill voice. It's easier to understand that way.

Jaykaying, Johnsned51, jkjk...
I actually learned something. Thank you.

Harbor Freight Tools sells the necessary adapter.


Jeffster3 years ago
Just found this link.... not sure about the availablity of these but it looks like a solution down the road.

Interesting, but the valve is incompatible with camp stoves, lanterns, torches, etc. It may have limited usefulness for propane-powered engines.
ironLes42 years ago
were can you find the adapter?
Harbor Freight Tools has them for 20.00.
twhite1016 years ago
How about warming it, then releasing the pressure then do this step. This should make more of a vacuum in this tank.
how about spending the money for a propane tree and extension hoses that attach to your large tank, then you can run your lantern, stove, tent heaters and the like off of your large tank and stop wasting time with this nonsense of collecting small tanks and refiling them. Here is a link, but I'm not advertising lol. look around the net for your best buy. http://www.amazon.com/Texsport-30-Propane-Distribution-Tree/dp/B000P9CZXQ
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