by disposable bottles I’m referring to the Bernzomatic disposable bottles that are the same size that the disposable propane bottles come in… I don’t know if there are cheaper ones… Steve
Small propane tanks, especially those that are a small diameter probably don’t have enough liquid propane exposed to boil off into gas to keep up with a tip. This may be why Paige recommends against using these tips on smaller tanks. I use the shorter, larger diameter, camp stove tanks with my Meco and larger Paige tips and they seem to work fine. I use an EZ Torch from Otto Frei, also on a camp stove cylinder, for annealing. It works great. The flame is larger and bushier making it easy to get the whole piece up to annealing temperature quickly…Rob
Yes, we’re talking about the same tanks. I just looked them up at Ace Hardware (that was the first place that I found them). The Bernzomatic disposable oxygen tank has 1.4 oz of oxygen. The same size Bernzomatic propane tank says it has 14.1 oz of propane. Interesting - Thanks for doing the calculations!!
Jeff
I use the 16 oz camp stove propane tanks too. I sometimes get them on sale at the end of the summer for $2 each!
Jeff
I just paid $12 for 2. They were a lot cheaper several years ago but, for me, they last up to 3 months of everyday use…Rob
Have a look at my YouTube video Disposable Oxygen Bottles for an Oxy Propane Jewellery Torch. - YouTube
where I do a demo and explain the science behind the 40 tanks of oxygen to one tank of propane.
Milt
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propane lasts a long time… I’ve done virtually everything suing propane air… using oxyacetylene or oxypropane works fast for melting and gives superheat for a good pour when using an ingot mold.
I looked up the price of disposable oxygen bottles and it’s $15 at Ace Hardware… too expensive… takes too much oxygen to do anything with such a small supply… 1.4 ounces is just shy of 40 grams…one mole of O2 takes up 0.8 cubic feet at sea level pressure and room temperature… 40 grams is around 36 grams… very little oxygen in a disposable bottle… correct me if I’m wrong, Milt… Steve
sorry for the error … 32 grams is about a mole of oxygen…40 grams isn’t much more than a mole…
the cheapest way to by propane is in refillable gas grill bottles that hold 20lbs. With adapters and a single stage regulator I’ve hooked them up to a full sized oxyacetylene torch for melting. for jewelry purposes, it would last almost forever, but you can still use them on your gas grill…
Steve , yes, one mole of any gas has a volume of 22.4 l or about 0.8 ft3 at room temp and pressure One mole of oxygen weighs 32 grams. But we are talking too much chemistry here. In my u tube video, i eliminate the need for chemistry by actually weighing the amount of propane that you burn with a full disposable oxygen cylinder…
Milt
thanks Milt, I loved that video… buying disposable oxygen bottles cost too much. I never used more than a propane air Bernzomatic to fabricate and solder. Oxygen and gas does help melting. I think you did a good job in pointing out how much oxygen it takes to burn a gas…I do have a question for you. I’ve used the old MAPP gas, propadiene/methylacetylene that came in the same kind of bottle that propane did and screwed into the propane air torches that Bernzomatic made. I did not find that MAPP/air burned much hotter than just propane/air. If it did, it wasn’t worth the cost. Why would that be the case? Theoretically it should burn much hotter…Steve
I know that people do it. I know that I used to, but 20 lb propane gas barbecue tanks should never be used indoors. The forum is filled with info about why. They’re not legal indoors in any US state.
I do know one jewelry artist whose entire house blew up because of an indoor propane barbecue tank connected to a jeweler’s torch. It created an insurance nightmare, because it was an illegal set up.
Because there are a lot of beginners who read this forum, I’ll always mention this when people bring it up propane barbecue tanks. I always recommend that people follow the rules of their state, county, city and insurance company when creating a jewelry studio torch set up, especially in a residential neighborhood.
All that said, this thread is incredibly interesting! I knew that disposable oxygen tanks were a bad deal, but big thanks to jsfandskh and milt for doing the math to explain exactly why!
Jeff
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Thanks for sharing this video Milt! Excellent explanation. Very helpful info!
Jeff
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I’ve never done that indoors… If I have to melt and pour ingots for rolling, I’ve tried it a couple of times, using a barbeque bottle, but always outdoors. Melting and pouring is very dangerous since any spill of molten metal will instantly burn anything flammable it touches. I’ve always done melting and pouring outdoors. Since I have acetylene, using it works even better, as it burns so much hotter. I can say that propane oxygen burns very hot at 4,600 degrees. Acetylene burns hotter but by weight, propane contains more heat energy per molecule… Indoors, I just use a Bernzomatic air/propane torch. The camp stove bottles seem to work better with a more steady pressure than the thin taller ones… Someone mentioned that they also found that using disposable camp stove bottles worked better also.
That’s great to hear! Good for you. You’re smarter than me! Like I said, I used to use a 20 lb propane tank indoors for all of my casting, ingot making and torch work, but once I heard about the propane tank exploding, destroying the house and the subsequent insurance nightmare, I quit that.
Now as the forum moderator, I’ve got to make sure that we don’t accidentally steer beginners in the wrong direction.
Thanks for your contributions Steve! You sure know your stuff!!
Jeff
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Many of us use the 1 lb tanks because we want to minimize the amount of propane we have in the studio. At my current local price of $3.89/gallon, a 20 lb tank takes 4/6 gallons, which costs $17.89, or 89 cents per pound. Lots cheaper than the 1 lb tanks, which are $4.47 each in a pack of 4 at my local Walmart. You can buy an adapter to refill your 1 lb tanks from the 20 pounder for $5.89. The Ebay title is: “Propane Refill Adapter Fill 1 Pound Bottles from 20lb LP Gas Tank Camping Heater.” You can’t get a whole pound in the tank, but close…the instructions are all over the internet, just Google it. -royjohn
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royjohn…I have both the simple $10 refill adapter and a refilling tank kit that includes a stand for the 20 lb tank to hold it in an inverted position, on/off valve, a fitting to attach a 1 lb. tank and cylinders designed to be reused. They all work fine, but for me it’s just easier to follow the sales and buy new full cylinders a couple times a year. I also found that the refillable cylinders did not seal very well on one of my torches. I am glad to have this option should I run out of propane on a day when I can’t find it at whatever store is open. I agree, my main motivation for going to this system was to get as much compressed gas out of my shop as I could and still use my torches…Rob
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Yeah im using the small ones inside. Im too nervous. Thinkjng of getting the smiths Acetylene silversmith torch and tank kit for melting or the electric melting kit thst looks like a kiln. What is the safety of Acetylene? Can i keep the tank outside? Which is a better choice?
Wow! Crazy.
What I like about the Smith’s air/acetylene torches is that they are simple and versatile. They’re atmospheric torches, meaning that they get their oxygen from the atmosphere. There’s no extra oxygen tank.
Which torch is safer? That’s a tough one to answer.
I will say that most schools that I have either been a student or a teacher at have air/acetylene torches (smith or prestolite) because they are so simple and versatile to use.
Jeff
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