Until I decided to switch to Smith Little Torch and oxygen concentrator setup I’ve been using hand held butane torches but if you have used a “real” jewelers torch before you might be familiar with the setup with large gas tanks as pictured above on the left.
Now there is nothing wrong with that setup if you know and follow proper safety procedures but it can be intimidating to new users and you can sometimes wonder at night if you really did close that gas regulator before you left your studio 🙂 Especially if your studio is also your home.
Talking about your studio being your home – having these large tanks at home breaches many homeowners and renters insurance policies. If that is your situation or if you just don’t feel good about being around the large gas cylinders you might be interested in the alternative setup with oxygen concentrator and a disposable – in my case propane – tank.
The oxygen concentrator with disposable gas tank is generally considered safe enough to be allowed under majority of homeowners and renters insurances – always double check with your insurance company though. Mind you, that doesn’t mean there are no risks at all, you always have to properly follow the proper procedures around flammable gases and accelerators – oxygen.
If you’ve never heard of an oxygen concentrator it’s a medical device used to provide concentrated oxygen to ppl who need it. It doesn’t store oxygen in itself, it concentrates and “makes it” from the air around it as it runs which makes it generally safer than the pressurized cylinders. The small disposable propane tank still contains a pressurized gas but a very small amount compared to the large tanks – 14.1oz for the small cylinder vs the large ones are usually around 5-20lbs.
Another advantage of using an oxygen concentrator is that you don’t have to deal with the logistics and price of refilling your oxygen tanks (or buying disposable ones). Running the torch consumes significantly more oxygen than propane so having unlimited supply is nice.
Upsides of using oxygen concentrator setup:
- safer than having large oxygen cylinder
- typically allowed by homeowners/renters insurances
- with heavy use can save money in the long run
- convenience (you never run out of oxygen)
Possible downsides of oxygen concentrator setup:
- higher initial purchase price
- the machine is large
- produces a bit of a noise when running – some brands and models less than others
- needs electricity to run so you’ll need to place it near a power outlet
- lighting and shutting off the torch works a bit differently than with the usual setup and might take some getting used to.
- most medical oxygen concentrators will start beeping if the oxygen output is too low (they think there is a kink in the line). If the machine has been repurposed for use with torches this shouldn’t be a problem but if you are buying a used medical unit, make sure it will allow you to choke the oxygen line enough as not to blow out flames on small tips without starting to beep.
Buying an oxygen concentrator
Probably quite obviously you’ll need an oxygen concentrator machine 🙂 Here you have several choices – you can get these already repurposed for use with a torch from sellers like Riogrande or sellers that sell equipment for glass blowing. You can expect these to cost you $400+. You can also get these used from craigslist or facebook typically from people that have been using them for their medical needs. Here you can get these for as cheap as $20-$150 if you look for a while but you get no warranty. Mind you these are complicated machines and if something breaks getting it serviced without a warranty can easily cost you $300+ (I am basing this on quotes I saw advertised by service companies and cost of the parts for my concentrator).
Each machine has a meter on it that shows how many hours it has been run for. If you are buying a used machine check what the expected life is for the specific model and see how close to the end of life the machine you are considering to buy is. Also if at all possible test run it for at least 20 minutes. Some models can take that long to start producing maximum purity oxygen and also start giving you warnings if they self detect a malfunction.
In general it is helpful – if you are buying an older machine – to lookup it’s manual online and get familiar with it before you go test it so you know what the different control lights and sounds are.
Most of the medically used oxygen concentrators have a maximum flow rate of 5LPM which stands for 5 liters per minute. Note that flow rate is not the same thing as pressure (PSI). Most concentrators have a preset pressure, you’ll need to check details of your specific model – e.g. my DeVilbiss 515ADS has 8.5PSI. In general the 5LPM concentrators have enough power to take Smith Little Torch through its paces. If you need more power – which comes at a higher price – you might want to look into higher LPM versions – 8LPM or 10LPM. You can also combine multiple concentrators which doesn’t give you higher pressure but it does give you more oxygen.
Components of the oxygen concentrator setup
Here is a list of parts I use for my torch setup. Not all oxygen concentrators come with B type fitting but more on those later.
My setup:
- DeVilbiss 515ADS oxygen concentrator
- Smith Little Torch all fuel kit with hoses with B type fittings. It’s a good idea to tie the excess length of the hoses and make sure it’s out of your way so you don’t trip over them or run them over with your chair increasing the likelihood of leaks. If you are interested in getting Smith Little Torch you can also check out my article on avoiding counterfeits.
- Bernzomatic disposable 14.1oz propane tank. Make sure your propane tank is secured to a table leg or something similar so it doesn’t get accidentally knocked over.
- Smith preset regulator for the disposable propane tank
- Miller regulator side mounted flashback arrestor for the propane line (be careful as torch side mounted flashback arrestors are also offered but won’t work with this setup). Also make sure that you’re buying a flashback arrestor and not a simple check valve. You don’t need a flashback arrestor for the oxygen concentrator. It won’t actually work properly if you install one. You might though consider this check valve from Paige tools to prolong the life of your machine.
As mentioned before some concentrators don’t come with the convenient B fitting but come with hose nipples instead. For these you will need a few other parts in order to connect the hose securely. If your machine comes with the hose nipple I recommend you watch this youtube video from Leslie Kail Villarreal where she walks you through her setup with EverFlo oxygen concentrator and what parts to buy to connect the hose.
For your convenience here is a list of the parts Leslie mentions in her video:
- A few feet of clear PVC hose with 1/4 inch inside diameter (that should fit the hose nipple on your machine, but double check)
- Hose to B fitting adapter parts:
- Airgas parts (cheapest): RAD 6400 3995 (coupler); RAD 6400 3987 (nipple); RAD 6400 3986 (nut)
- Amazon alternative: Forney 60332 Hose Coupler Set & Forney 60326 Hose Repair Kit. Note that you don’t need all the parts but I didn’t find them listed separately for a better price.
Check for leaks
Anytime you assemble a new setup or reinstall any part check for leaks. Leaks can typically occur around connections – connection of the hose to oxygen concentrator, connection of regulator to the propane tank, to the flashback arrestor, to the hose and the torch. But leaks can also occur on the hoses themselves and on the torch body so make sure you check those too.
You can check for leaks using a specialized solution or a water with dishwashing liquid and apply it to the joints using a toothbrush. If you have a leak the escaping gas will form new bubbles in the solution. You can check for leaks on hoses and the torch body by submerging these underwater and looking for bubbles. For this test to work you need to make sure there is gas feeding into the system. If you discover a leak do not use the equipment until you fix it. If the leak is on the joints sometimes the fix is as easy as tightening the joins or using a teflon thread seal tape. If you are unsure how to fix things, search out a professional – oftentimes folks at your local Airgas store might be willing to help or at least point you in the direction of a local welding equipment service.
Tip: the threads on the fuel line components are reversed so watch out. It means it’s lefty tighty, righty loosey 😉 This is on purpose so that you don’t mix up incompatible components and typically these connections will have notches in the nuts.
Step by step on turning on/off your oxygen concentrator powered torch
Here is the list of steps for turning on/off the oxygen concentrator setup with a disposable propane tank. I put it together after doing some research and discussing it with other users. If this is your first time using a torch like this I recommend having an experienced user or somebody from a welding shop check the setup for you and walk you through the steps.
Turning the system on:
- Make sure your fuel knob is closed and your oxygen knob is open
- Turn on the oxygen concentrator and let it run for a few minutes (it takes time for it to start producing the highest purity oxygen possible). It is important that the oxygen knob on the torch is open as oxygen concentrators will typically start beeping loudly if the flow is blocked. It’s a medical device supposed to keep somebody breathing so it will think the line got kinked or something like that. If you forget and the beeping starts just open the line and it should stop soon.
Note: I have the machine always set on maximum LPM but with the hose and the torch connected the actual LPM is lower as the flow rate is restricted by the diameter of the hose and by the oxy knob torch valve (how much you have your oxy knob closed or opened). - Once the concentrator has been running for a while it’s time to open your fuel gas regulator (keep the line still closed on the torch side). You are now ready to light the torch.
Lighting the torch:
I was taught the POOP way, that means when lighting first turn on propane, then oxy and when turning off first turn off oxy and then propane. I know that some people do it another way but this works for me.
- Get your lighter – whichever type you are using – ready.
- Close the oxygen line (by this I mean close your oxygen knob on the torch), crack open the fuel gas line and light it.
- As soon as it’s lit open your oxygen back up gently. This might take some practice. For example my oxygen concentrator gives me just a few seconds before it starts beeping when I close the oxygen line so I had to learn to light it fast if I don’t want the alarms sounding 🙂
Turning the torch off:
- Close the oxygen knob
- Close the propane knob
- Open the oxygen knob again (your concentrator is still running and unless you want it to start screaming at you you better let it flow)
Turning off the system:
When you’re done for the day here are the steps to follow
- Turn the torch off as usual
- Close the propane regulator
- Turn the oxygen concentrator off
- Close the oxygen line temporarily and bleed out the propane line. In order not to bleed the propane unburnt into your home you can instead light it (the same way as if you were lighting the torch, just don’t add oxy) and let it burn out.
- Close the propane line (always keep it closed if you are not using it) and open the oxygen line. There will be some oxygen flowing from the torch for a while as all the oxygen still in the concentrator releases. You can keep this line open.
That’s it. It is also a good idea to take off the regulator from the propane bottle if you won’t be using it for a while to store it.
Tips & Tricks
How pure is your oxygen?
Some oxygen concentrators have purity indicators built in. If yours doesn’t or you are still in doubt the concentrated oxygen is pure your flame color is also a good tell tale sign. If, after you mix in oxygen, your is red-ish or orange-ish it might mean low purity of oxygen. This can be caused by leaks somewhere in the setup, the oxygen concentrator needing more “warm up” time or some issue with the concentrator.
When the oxygen smells
Oxygen concentrators concentrate oxygen from the air in the room around them. While doing that they might also seemingly concentrate some smells or start reeking of some – for example cigarette smoke. Also mold can develop on some parts if the concentrator has been kept in humid conditions. Make sure to regularly wash the main air filter (as often as weekly) and if needed you can try to take off the machine cover (when unplugged) and see if you can see any dirt or mold inside. You can wash the filter in water with dishwashing soap. If in doubt check the manual for maintenance instructions.
And that’s all folks. It was a long post but hopefully it helped somebody! 🙂
Alice in Jeweler's Land 