Anybody refill IsoButane canisters?

Discussion in 'General Survival and Preparedness' started by gunbunny, Jun 5, 2010.

  1. gunbunny

    gunbunny Never Trust A Bunny

    I've been doing some research on the fuel used to burn in a "pocket rocket" lightweight folding camping stove. I have a couple of different stoves, a Brunton, Giga Power, MSR, etc. They are defenetly NOT the same.

    Neither is the fuel. Brunton, Coleman, MSR, Giga, and a few other brands make the fuel vaguely described as IsoButane. Each brand has it's own makeup, but usually just a blend of two different gasses: Propane (LPG) and Butane (n-butane). Most seem to use a mix of 80% Propane and 20% butane.

    Some stoves are butane only, like some of the Brunton units. Most seem to be IsoButane fuelled, but only the larger and heavier burners can use straight propane.

    What I'd like to do is refill my little 4 or 6oz canisters. Usually they are considered disposable, for a single use only. I don't see why I can't refill the canisters like a scuba shop refills Nitrox tanks. They use pure O2 to a certain pressure, then fill them up the rest of the way with air. This loweres the amount of Nitrogen in the mix, and allows for quicker rest stops between dives, deeper, longer dives, etc.

    Anyway, knowing the weight of a full canister, fill with butane to an amount 20% of the full weight, and then fill with propane the rest of the way.

    Why? Because it has to be cheaper then buying a bunch of IsoButane canisters when you could refuel a dozen or so from a 20lb LPG bottle and some butane.

    The questions are: Where can I get Butane in bulk? I would only need 4lbs of butane to a 20lb LPG tank.

    Where can I get adapters that would fit on the canister? I looked into getting a remote stove stand from Brunton that has a female end for the IsoButane canister, and take it apart at the other end and adapt it to fit a 20lb LPG tank. The next problem is, how can I get Butane? Is it sold in bulk? What type of an adaptor do I need to make to make the whole thing work?
  2. gunbunny

    gunbunny Never Trust A Bunny

    I take it that nobody has tried to refill one yet? Is that from a lack of equipment, gas, or because you think it is too dangerous?

    I did a little more research and found bulk Butane. I don't think I could burn through 20 lbs of butane in my lifetime...
  3. melbo

    melbo Hunter Gatherer Administrator Founding Member

    It makes sense but I've never looked into it. I use those cans for my JetBoil and think about what a waste it is to toss those cannisters.
  4. gunbunny

    gunbunny Never Trust A Bunny

    I got some more info on the canisters. They have 7/16 NS threaded Lindal resealable valves. These are a standard valve for EN521 appliances. In Europe they are called "universal EN417" canisters.

    So, I guess I have to find an old EN521 appliance and scavenge the female end of the valve. I'm sure I could find the correct fittings and attach it to a standard propane adapter- even the small blue propane canisters.
  5. ColtCarbine

    ColtCarbine Monkey+++ Founding Member

    Refill Disposable Propane Cylinders!

    April 17th, 2008 · by Tim Flanagan, Managing Editor<!-- 60 Comments-->

    UPDATE: check out this more recent post to learn how I assembled my own super-duper propane refill adapter!
    It’s my new manifesto, sort of. See, these 16-ounce "disposable" propane cylinders are such a convenient size for camping and cruising on smaller boats, sometimes there isn’t any other alternative. In the lazarette aboard Two Lucky Fish, A C-Dory 22, this is really the only propane storage solution that doesn’t involve a costly custom propane installation.
    So go ahead and use the 16-oz cylinders if you can’t fit one of the DOT-approved refillable cylinders. It’s a shame that even major suppliers such as Coleman have no recycling recommendations for them.
    But I’ve learned that they CAN be refilled. The reason you don’t hear much about it, though, is that 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.

    Obviously, because it’s propane, you need to handle it properly and observe all the best-practice safety protocols.
    [​IMG] First thing, though, you need to purchase one of these little adapters from Mr. Heater or one of their distributors.
    I got mine at Joe’s (which was G.I. Joe’s when I was a kid, and actually sold military surplus gear, but I digress). Cabela’s sells a similar item called the Mac Coupler, and it’s worthwhile to read the negative reviews on their site.
    The negative reviews, which are by far the minority, describe some of the difficulties people experience using this adapter. This can be helpful, because there are a few tricks to refilling these cylinders. To obtain the best results, it helps to understand a little bit about how propane works.
    At normal atmospheric pressure and temperature, propane is a gas. It’s heavier than air, so it will tend to settle and collect in low spots, such as the bilge, cockpit, or cabin of a boat. That’s what creates the explosion risk when there is a propane leak, and that’s why propane storage locations must be designed to vent overboard, not inboard. This is absolutely crucial. Don’t cut corners here.
    The propane we purchase is "Liquefied Propane Gas" (LPG), which has been compressed into a liquid and is stored in cylinders designed to keep the propane compressed. The propane is always under pressure, and will tend to escape if you let it. So the integrity of your storage cylinder is another extremely important safety factor. Don’t skimp. I don’t know what the lifespan of refilled "disposable" cylinders is, but if they leak or they’re visibly damaged, it’s time to get ride of them.
    Myth: larger propane cylinders generate more pressure than small tanks. This is false, they all generate the same pressure, which is dependent on temperature. Lower ambient temperatures produce lower internal cylinder pressures. Higher temperatures produce higher pressures. That’s why one of the guidelines for refilling disposable propane cylinders is not to do it in direct sunlight or on hot days; you could be dealing with very high pressures indeed under those circumstances.
    See, what happens inside the cylinder is that the liquid gas vaporizes just until the pressure is sufficient to prevent additional vaporization, which depends on the temperature.
    Pressure keeps the propane a liquid, right? And the vaporized propane gas exerts pressure, right? So just enough of the liquid vaporizes to maintain the pressure inside the cylinder to prevent any more of the liquid propane from vaporizing. Got it?

    Then you come along, open the valve, light your grill, and thereby release some of the pressure inside the cylinder. Propane abhors a vacuum, so the liquid starts vaporizing again to "fill the vacuum" left behind due to your cooking.
    So here’s an interesting feature of propane systems: As long as some liquid propane remains in the tank to vaporize, whether it’s 90% full or 10% full, the pressure inside the cylinder remains constant. That’s why you can cook just as well with a nearly-empty tank as with a full tank.
    OK, back to the subject at hand: refilling disposable propane cylinders. The goal is to move LIQUID propane into the empty cylinder. It does no good to move GAS into the cylinder. The heavier liquid sits at the bottom of a cylinder, and the lighter gas sits at the top.
    So there are two tricks involved in getting liquid out of your big DOT-approved cylinder and into your small one. First, you need to turn the big supply tank upside down, so that the pressure inside the cylinder pushes liquid, not gas, out through the valve.
    Second, you need to create a pressure differential between the supply cylinder and the cylinder being refilled. There are two ways to do this: The official way is to chill the empty cylinder. Remember how propane pressure depends on the ambient temperature? If you can keep the supply tank at room temperature and chill the empty cylinder in the fridge for 15 minutes, you can create some temperature differential, and therefore some pressure differential.
    But even so, many users report that they only get about a half-full cylinder this way. It may take some experimenting to get it to work optimally. Chill the empties longer? Freeze them? I’m not really sure. Feedback from readers is most welcome on this!
    To get a full refill, you could reduce the pressure in the cylinder another way, though. It’s possible, I learned, to take a pair of needle-nose pliers and pull the pin on the pressure relief valve of the cylinder you’re refilling. This reduces the pressure and allows the liquid propane to fill the cylinder.
    If the instructions that come with your refill adapter don’t mention this method, though, it’s probably because it entails more potential risk than the manufacturer’s liability attorneys are willing to accept. Obviously, you should not use these refill adapters in any manner that differs from that described in the documentation.
    Still, if you were to give it a try, as I did, you might discover that it works so well that you can overfill an empty propane cylinder. I used a postal scale to compare mine to a new, full cylinder, and I got about two ounces more into the cylinder using the pull-the-pin method. So if one were, hypothetically, inclined to use this method, which one should take care NOT do, of course, I would strongly urge one to weigh one’s cylinders to ensure one is not overfilling them.
    Regardless of the method you use, though, 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. I had some extremely slow leakage from my overfilled cylinder, barely perceptible, coming out the pressure relief valve. I left the cylinder outside overnight where the propane would tend to dissipate and not collect. In the morning, the cylinder weighed about the same as it had the night before, but it was no longer leaking. I assume the relief valve was working as designed.
    I cooked with it at home until it weighed the same or less than a new, full container, before taking it to the boat. I cooked aboard the boat last week while the kitchen floor was being refinished at home, and now I’m cooking with this cylinder at home again. It seems to be working just fine.
    I’ve intentionally avoided providing a step-by-step procedural description of the refill process. I’ve probably put myself at enough risk here already! The adapters all come with instructions, and you should follow them.
    For liability purposes, I should once again advise you NOT to pull the pin on your cylinder’s pressure relief valve. If you do so, you do so at your own risk.
    Hopefully, though, I’ve given you enough background to understand how the process works and why the instructions are written the way they are.
    Last edited by a moderator: Jun 1, 2015
    kellory likes this.
  6. ColtCarbine

    ColtCarbine Monkey+++ Founding Member

    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...


    [​IMG]step 1
    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.

    [​IMG]step 2

    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:

    Link For Cabela's :

    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

    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

    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

    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

    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

    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

    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

    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.
    kellory likes this.
  7. ColtCarbine

    ColtCarbine Monkey+++ Founding Member

    The amount of money one would save doing this doesn't seem worth the risk to me.

    Have you ever seen what happens when a pressurized cylinder fails, let alone one that has a fuel in it?

    Would I do this, NOPE. My life is worth more than a $3.00 cylinder of propane. I'm not saying you couldn't do this like others have and be quite successful at your refilling.

    If you are lucky, you will only screw up this process once.

    To each their own, good luck!
  8. ColtCarbine

    ColtCarbine Monkey+++ Founding Member

    Last edited by a moderator: Jun 1, 2015
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