Step 4: 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.
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 &quot;Mac Coupler&quot;. It was intended to be used with their LP4585 refillable propane cylinder &mdash; 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. <br> <br>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.
<p>the Cabelas link the author shared shows that they must have discontinued too. but the link by BradS28 above works currently in 2016. </p><p>https://www.propane-refill.com/collections/refillable-one-pound-propane-cylinder</p>
<p>BradS, maybe you should mention that you are affiliated with propane-refill so we can all appreciate where you are coming from.</p>
<p>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.</p>
<p>OK. Enough nonsense about the dangers of overfilling. </p><p>Valid Concern #1) Vented propane is flammable and is a hazard once it's out of the tank. It's more of a hazard than you might think because once it's out of the tank it mixes with oxygen in air. Rather than the calm flame you see in a stove or lamp it can explode as it burns all at once.</p><p>Nonsense #1) The tank can explode if overfilled.</p><p>No one has been able to find a photo of a failed tank because there's a safety pressure-relief valve to vent it if need be. The tank itself will never fail. OK. Maybe if you remove the safety valve and replace it with a bolt. Somewhere around a thousand PSI.</p><p>Nonsense #2) <u>The pressure after filling is important.</u> </p><p>The pressure of propane vapor (a gas over some amount of pure liquid) is a function of temperature. Only. There's a graph. In the tank the molecules of propane go back and forth between the liquid and the gas. There's a balance reached between the evaporation and condensation rates. The evaporation rate depends on temperature but the condensation rate doesn't so the balance depends on the temperature. The warmer it is, the higher the pressure of the vapor. If there is <em>any</em> amount of liquid and <em>any</em> amount of gas, that graph is obeyed. Nothing you can do will change the vapor pressure. All tanks containing between 1% and 99% liquid have the same pressure if they are at the same temperature.</p><p>Nonsense #3) <u>The relief valve is carefully calibrated at the factory</u>. </p><p>It's set to a quite high pressure. It's there to stop the tank from rupturing. It's a steel tank. That pressure is high. It's somewhere around 360-480 PSI. That's something like 25 bar if you're looking at the vapor pressure graph. Put the tank in boiling water and the pressure will want to rise to double that. (The valve should open to prevent that). The tanks are required to have a minimum burst pressure of 960PSI so they are actually designed somewhat higher. Call it 1200PSI. There's a wide difference between those pressures.</p><p>Valid Concern #2) If the pressure relief valve opens it might not reseal well.</p><p>These tanks are meant to be discarded after a single use. The valves are c*ap. They aren't meant to open and close repeatedly so when they do open they have a closing-failure rate. Over time a small leak can release the entire contents into an enclosed area like your trunk or a storage cabinet and you're facing Valid Concern #1.</p><p>THE REAL PROBLEM WITH OVERFILLING </p><p>If you fill the tank to 100% with liquid, there is no vapor and the graph above no longer applies. I don't have the complete data on the physical properties but Wikipedia says that the volume wants to expand 1.5% for each 10 &deg;F. (there should be some pressure/compressibility terms decreasing that for our situation). If you nearly fill the tank then warm it up the liquid will expand, shrinking the gas until you have liquid pressing in all directions and then the pressure can rise very rapidly. How many 10's of degrees are between a frosty tank and the temperature in your car parked in the sun on a hot summer day? Looks like 80-85% full is about right.</p><p>Then Nonsense #4)<u> the tank will shred sending shrapnel in all directions</u>.</p><p>When an explosive bursts a container sending shards, it is, at its heart, an expanding ball of high pressure gas. Like a compressed spring, when you release it, parts fly around. </p><p>A 100% full tank though is filled with liquid. When the liquid ruptures the tank (if you defeat the safety relief valve) it's filled with liquid and it's just going to tear the tank and leak out. The liquid propane will want to change to a gas and throw bits around, but it needs heat energy to do that. It gets that heat from the liquid so the liquid cools down and that lowers the vapor pressure. Only some can evaporate before the bulk liquid is too cold to worry about. Its bomb-like-ness is limited, but again you're back to Valid Concern #1).</p><p><strong>My actual contribution</strong>: Put a piece of scotch tape over the safety valve to keep dust out of it. That might help it not leak.</p><p>Many of my numbers came from this report </p>
<p>Links were removed</p><p><a href="http://encyclopedia.airliquide.com/images_encyclopedie/VaporPressureGraph/Propane_Vapor_Pressure.GIF" rel="nofollow">http://encyclopedia.airliquide.com/images_encyclop...</a></p><p><a href="http://www.propanecouncil.org/uploadedfiles/council/research_and_development/rep_10202_battelle_cylinder_report_final.pdf" rel="nofollow">http://www.propanecouncil.org/uploadedfiles/counci...</a></p>
<p>Thanks MrDrSmith, for your well thought out myth debunking.</p>
<p>Really interesting instructable, although though my fear of fiery death and the fact that a full cylinder of propane is selling for 4$ at Canadian Tire ensure that I won't ever try this. :p</p>
<p>I wanted to show folks a couple of photos of our refillable propane cylinder valve. I am a factory rep and also sell these on my website propane-refill dot com as a safer alternative to refilling single-use cylinders. Not to mention that these cylinders are DOT &amp; TC certified like your BBQ tank as refillable and legally transportable so they save you money over time without violating any regulations. There is also another company making one pound refillable's but they do not work like ours do in nearly every appliance made for these cylinders. Our cylinders can be filled with our refill adapter, the small brass adapters mentioned below, as well as anything you can build yourself using industry standard fittings. I am only trying to get the word out to folks that they do exist so you do have a choice. Do what you like with the information.</p>
<p>BradS, maybe you should mention that you are affiliated with propane-refill so we can all appreciate where you are coming from.</p>
<p>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.</p>
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 &quot;refill&quot; 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. <br> <br>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.
<p>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. </p><p>Long story short. Its just as safe as filling anything else to 100-200PSI. Anyone with an air compressor does that often. </p>
yyyyyyyyep. I'm out. Thanks.
<p>Is it safe to remove a bbq tank from a bbq and move it to another bbq if its not empty?</p>
<p>Of course, Just close the valve. </p>
Does the BBQ tank have to be upside down?<br><br>I can't get more than 100g into my empty Coleman cylinders.<br><br>I just had my BBQ tanks filled by U-Haul.
<p>The usual recommendation is not to fill to more than 85%.</p><p>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.</p><p>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.</p><p>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.</p><p>The pickle jar had proportions similar to the Worthington. The results are probably different for different shape cylinder.</p><p>Ken</p>
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
<p>There shouldn't be any &quot;air&quot; (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.</p>
It's not a bleeder it is a safety vent for DOT regulations.
Correct. The valve is to vent excess pressure so the tank won't burst. <br>The valve may have been used to bleed air on the first factory fill. <br>But as you use the original fill, propane gas exits only. No air enters the tank. <br>The &quot;air&quot; in the tank is simply leftover Propane gas at a pressure of approx 1 atmosphere. <br>To vent this gas is wasteful and you run the risk of overfilling the cylinder too. <br>What happens then? As the temperature rises the pressure valve releases the extra, wasting more gas.
Chilling is unnecessary. <br>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.
The <a href="http://manuals.harborfreight.com/manuals/45000-45999/45989.pdf" rel="nofollow">instructions</a> on the adapter specifically say to chill the empty tank.
Thereby lowering the pressure some more allowing a little more to be drawn in from the fill tank. <br>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.
<p>Show us a SINGLE photo of an over pressurized and burst disposable tank.</p>
Because of the possible damage and death, overfilling is just not worth the little bit extra. Be safe, live long, and prosper.
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.<br /> <br /> #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!!!<br /> #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.<br /> #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. <br /> 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 &quot;0&quot; 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!)<br /> Big tank, big&nbsp; volume,gas cools slower, doesn't get to -44, burn hotter longer<br /> <br /> Better yet, just don't do it. state an federal agencies do'nt write rules to &quot;big Brother&quot; us. They may seem misguided sometimes but they really want us tobe safe
<p>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.</p>
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 &quot;empties&quot; and put them to use on my propane appliances to get every last bit of usable fuel out of them. <br> <br>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. <br />
Here's the dummies version: <br>#1&amp;2 <br>Gasses expand with temperature. <br>If Nit-wit fills a tank's total volume with liquid gas under pressure, there's no room for it to expand. <br>Tank bursts. <br>Ouchy. <br> <br>#3 <br>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. <br>The rest of the liquid gets so cold that it won't evaporate any more. <br>Nit-wit discards half full cylinder. <br>Half full tank has time to warm up again. <br>Smart guy picks up half full cylinder. <br>Litter Bad. <br>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. <br><br>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. <br><br>Have you ever seen the sort of explosion and the devastation that one of these can cause, it can easily kill. <br><br>So if you&rsquo;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. <br>
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!<br>
I don't think this is proper English: His post was totally readable. Legible maybe? or understandable?

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