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Smith Little Torch help!

Hey folks! New member of ganoskin here, I have been making jewelry as a hobbyist for a few years but am starting to invest in better equipment and build some new skills to start making & selling more seriously.

I’ve been using a Smith Little Torch with disposable tanks and Smith gauge-less regulators for about three years. I typically buy disposable oxygen & propane tanks in bulk. However, after purchasing an alarming amount of “dud” oxygen tanks, I’ve decided to upgrade to a heftier fuel system.

I’ve purchased medium duty regulators and flashback arrestors. Today I ran out of my disposable oxygen and decided to purchase my first big oxygen tank. My question for the community is; can I use a large oxygen tank on a medium duty regulator while using a disposable propane tank with the smith gauge-less regulatory? While I’m sure my flame wouldn’t be as precise as possible given the gauge-less style of the disposable propane tank regulator, I would really like to use up the 10 full disposable propane tanks I have before buying something heftier. My only concern is what safety hazards this may entail.

Any and all advice is much appreciated!

What are you doing with your torch? Many of us use non-regulated propane from a 1 lb. camp stove cylinder and O2 from a medical O2 concentrator. I run both a meco midget and Little Torch in tandem through Y connectors and can do whatever I want in silver and gold to include 2 oz. melts with this setup. I have never used small O2 cylinders, but when I ran regulated propane or acetylene and regulated O2, I used it at around a 1:4 ratio of gas to O2. After a lot of research prompted mainly by the desire to get the high pressure cylinders out of my shop, I settled on the arrangement described above. I would add that I use Paige tips on both torches and they make a big difference. With these tips I am almost to the point where I use my Meco very little as the Paige tips allow me to do most of my work with the Little Torch with the exception of casting. Do a search in the archives regarding your questions and you find a lot to consider. Safety is not addressed a lot for obvious reasons. You might talk to a welding professional about what you are proposing, but I would worry a lot about flashback. Good luck…Rob

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Hello Rob. Would you mind posting a picture of your camp stove cylinder setup? Any idea what kind of pressure is in that sort of cylinder? Andrew

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Look at the shop shot pictures on my website: www.robmeixner.com. I don’t know the pressures, I just know the setup works. Good luck…Rob

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Hi Lars,
I use a 1 lb propane tank with a regulator…you will just need to get a propane or acetylene regulator (they are the same) and they are not expensive, maybe $30, maybe a little more if you want a better one. You will just need some adapters to run it on the 1lb tank, but your local welding shop should be able to tell you what you need in the way of adapters…you can probably find these on ebay, too. As Rob says, I would consider an oxygen concentrator…a 5 lpm concentrator is adequate for jewelry making unless you are melting a lot of metal. You might find a used one for sale in your area, as folks get sick and need these and then die and leave them to heirs…it is not legal to sell these for medical use without refurbishment, so you might find one cheap. Or look for a refurbished one from someone in your area who repairs these…a whole lot cheaper than a new one from the local medical supply or Rio. You should be able to get away for about $350 and then you have a very safe source of oxygen that will last for years. Look at some of the discussions here on the care and feeding of one of these. They run about 10,000 hours before needing major work, so that’s a whole lot of jewelry making. As far as LT tips, I have found that the acetylene tips with the little hexagon nut on the top to give multiple flames seem to work with propane as the Paige tips do for less money. -royjohn

Regulators, Disposable Cylinders , Gasses , Safety Devices & Torches are products of interests to most jewelry makers. Discussions involving these topics often come up on Orchid. Paige Tools believes operating gas equipment ‘safely’ is the skill most fine jewelry makers should master First. That conviction motivated us to comment further on some of what’s been said about these products plus review areas we consider most important & add a little information to the discussion hopefully benefitting general gas products knowledge & Torch use safety.

Paige Tools makes specialized Tip products for many, popular Torches. We also have years of experience in related products mentioned in the first line of this post. We design for Propane & Natural Gas because we believe they are the Best Choices for most precious metal work but also do testing using acetylene & hydrogen for some products / processes.

Side comment: Hydrogen / oxygen is an excellent choice for platinum casting with it’s high heat and super clean flame but it should Not be used for working on palladium or palladium alloy white golds. Palladium has an affinity to absorb hydrogen potentially causing it to become brittle.

The Little Torch & Meco Midget frequently mentioned here are ideal Torches for typical jewelry making. Torch cost or construction quality are not nearly as important to successful Torch work as matching the Tip design to the fuel gas being used… a point not often stressed. Using the correct Tip design both above Torches perform equally. Unfortunately, single orifice Tips that come with most Torches are Not correct design for Propane or Natural Gas. Single Orifice Tips are correct when using acetylene or hydrogen. Using the correct Tip design makes a BIG improvement in flame performance allowing beneficial aspects of the fuel gas to come forward like much more heat output & flame stability, etc. Information we explain in more detail in our Newsletters and to people calling for Tech help.

Disposable Oxygen Cylinders: Most of the people we’ve spoken with that have used these cylinders -for jewelry making- consider other oxygen options fairly soon due to their high cost & limited run time. Disposable oxygen cylinders only contain a small amount of oxygen. More oxygen is also used than fuel gas during typical Torch work which contributes to oxygen running out faster than a fuel gas. Additional information about Disposables below.

Oxygen from Refillable Tanks has some advantages over other oxygen sources but also some drawbacks. Oxygen tanks are pressurized to about 2000 PSI. Thick, tank steel walls allow that pressure. Disposable cylinders (oxygen & fuel gas disposables) have very thin steel walls so oxygen pressure is limited to about 400 PSI in new cylinders which reduces the amount of gas they contain. Oxygen from both refillable Tanks and Disposable Cylinders is over 99% pure oxygen. High purity oxygen allows producing the hottest Torch flames!

Oxygen Concentrators have become very popular as a convenient option. Oxygen they generate generally runs in the 90-95% purity range from newer machines in good operating condition. One drawback of Concentrators is fairly low output PSI. Very popular 5/LPM Concentrators typically output around 6-7 PSI. Even 10/ LPM units with double the oxygen volume output only increase PSI output about 1 PSI.

A Concentrators basic function is removing Nitrogen from the ambient air. Nitrogen composes about 78% of the air we breath. Pure oxygen composes roughly 20% of air. The remaining components of air consists of H2O (water vapor) , CO2 & micro amounts various nobel gasses . Concentrator filters remove most of the nitrogen which accounts for the 90-95% oxygen purity they produce. The other 5-10% of gas from a Concentrator is made up of the substances noted above.

To protect Concentrator filters from becoming contaminated by fuel gas backing up in a Torch (that can happen) then flowing down the oxygen line to the concentrator a Check Valve should be installed on the Concentrator output. This is a one-way valve allowing oxygen out of a Concentrator but blocking any gas from going back into the Concentrator and contaminating its filters.

Disposable (camp stove) Propane cylinders are Very economic . Low cost with a good run time. Propane is filled as a liquid in all sizes of propane cylinders & tanks… hence the term LPG, Liquid Propane Gas. Propane pressure (PSI) inside containers varies depending on the temperature of the container which is typically determined by ambient air temperature around the container. At 30 F pressure inside the propane container is about 50 PSI. At 80 F almost 130 PSI increasing in pressure (PSI) as the container temperature increases. Propane automatically changes between a liquid and gas state based on its temperature; a process called Vaporization . Conversion back to a liquid state from the gas state is called Liquefaction and depends on temperature & pressure (PSI) in the container.

Take away minus Tech talk: Propane is a great fuel gas for jewelry making. Low cost & clean burning producing plenty of heat when combined with either all oxygen sources for working with all precious metals.

Acetylene combined with ‘Tanked’ oxygen is the ideal fuel gas for welding steel but overly hot for jewelry work. Its concentrated flame is Not as clean burning as propane and not as safe a fuel gas as many people may assume! Google: 15 PSI warning about acetylene . Information to keep in mind when choosing fuel gas options for precious metal work.

Disposable Cylinder Regulators have *one function. They reduce gas pressure from the disposable cylinder high pressure to a fixed, low PSI output. *(An exception noted below.)

Traditional Regulators have one or two pressure Gauges . These regulators preform 2, functions. Gauges indicate gas pressures in PSI of a source gas or output PSI to the Torch or both pressures simultaneously on dual gauge regulators. The function of reducing high pressure of the source gas is the same function of regulators used on disposable cylinders but traditional regulators are a much more robust product. Their 2nd, very handy, function (feature) allows adjustment of the output pressure over a wide, PSI range. *Some Disposable Cylinder regulators also allow adjusting the output PSI monitored by a single gauge.

Traditional Regulators are also referred to as Single & Dual Stage models plus several levels of construction quality .

Single Stage traditional regulators drop the high pressure of an oxygen or fuel gas source down to a much lower pressure in one, step or ‘stage. New , single stage regulators work fine at holding low output PSI settings but as they age the set output pressure will begin to creep up or down and must continually be readjusted.Rebuild cost of single stage regulators is often close to their replacement cost.

Dual stage traditional regulators drop the high pressure of a gas source down in two, steps / stages. Dropping pressure two steps (think 2000 PSI oxygen Tank pressure dropped down to about 100 PSI) stresses regulator components far less and provides a much longer regulator life span. Dual stage regulators are also able to hold low output PSI settings over long periods; often some years. Mainly used in commercial operations, medical & laboratory environments. Dual stage Regulators generally are cost effective to rebuild if needed.

Light duty, Medium & Heavy duty Regulators all work fine with all oxygen & fuel gas refillable tank sizes. Component materials inside a regulator are the primary factors determining the duty level roughly indicating how long the regulator should last under normal use.

** Regulator Take Away : Paige Tools recommends Light or Medium duty, Single Stage models. Costs of Heavy Duty & Dual Stage units, in our opinion, do not bring enough benefits to justify their cost. Well respected brands like Victor, Uniweld, Harris & Smith are standards across US industries. You Do Not need to match brands such as using the same brand for your fuel gas & oxygen sources. Mix & match is commonly done.

Flashback Arrestors are ‘Good Practice’ products to use on Fuel Gas regulators with Disposable Cylinders & Refillable Tanks plus regulators used on all Oxygen sources except Concentrator oxygen. Just a Check Valve is normally used on an oxygen concentrator as mentioned above. Typical Arrestors contain both Flashback & Check Valve functions. A Flashback function reduces gas pressure a little, about 1-1.5 PSI. Oxygen from a concentrator is typically low pressure so maintaining its output pressure is important plus the a Flashback function is not really needed with an oxygen concentrator. With a Disposable oxygen cylinder a Flashback Arrestor should be used for as good safety practice. Regulators used on all Disposable Cylinders have enough PSI output to compensate for the small, PSI drop of the Flashback function. Regulators, Arrestors & Check Valve products use can be confusing. Give us a call with questions!

Good Use Practices: Small hand Torches used by most jewelry makers have limited gas volume throughput. They work great for typical soldering & annealing duties but for casting & larger ingot melts a ‘next size up’ Torch can really help. Torches like the Smith, AWIA, Victor J-28, Uniweld 71, etc., with robust construction and special Necks that allow different Tips to be attached and offer increased gas flows bring advantages. Paige Tools Tip products also support these Torches. Using slightly higher gas pressures & high purity oxygen from refillable tanks higher BTU (heat ) output can be obtained for larger or faster melting.

We encourage Torch users to be sure they understand the correct sequences of turning on/off a Torch and gas sources. How to adjust a propane / oxygen flame to reducing, neutral & oxidizing profiles is also very important. Maintenance of Torch & gas products is also part of the First Skill mentioned at the beginning of this post. Products knowledge & best practices adds to user confidence which helps in exploring new, creative processes & making discoveries. Give us a ‘call’ if you have questions. Our contact info & hours of operation are available on paigetools.com.

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Smith actually sells a setup to use a larger oxygen tank with a disposable propane tank. That is what I have used for years and it works fine. You probably didn’t have dud oxygen tanks, you just go through oxygen way faster than propane so it really doesn’t make much sense to use the disposable oxygen tanks. I bought an oxygen concentrator now too to replace my oxygen tank, I’m just waiting forever for that last bit of oxygen to get out of my tank.

Good luck and happy smithing
Bernie

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The gauge-less regulator is a fixed pressure regulator. The knob on the torch is what you use to control your flame. I’ve never had issues with the fixed regulator that came with the Smith kit. To this day I still use disposable propane cylinders. They are inexpensive, they last a long time and I don’t have to worry about a large tank that can leak and cause problems inside my workspace.