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Converting acetylene/oxy Little Smith Torch setup to propane/oxy

Hello fellow Orchidians,

I am an amateur at best and do not like the black soot that ends up all over the studio when using the acetylene/oxy torch. So… I’d like to update my setup, if possible, rather purchase a new propane/oxy torch or continue using plain old disposable propane-only tanks. As much as they’re ok for some things, they’re not so great at others.

I searched the topic and did not find a definitive answer to my question; Can I simply swap the acetylene tank to propane (using appropriate adapters, of course) with my current setup? Several posters say, change the acetylene regulator others say the existing regulator will work with propane. Some say change out the the hoses, others say don’t bother if they’re “T” rated.

I’ve attached photos of my regulators and handset (FWIW) to illustrate exactly what I currently have. As I mentioned, some of the posts said if the existing hoses are “T” rated, they’ll be fine with propane, but I cannot find any notations on the hoses. As you can see these are the Smith Little Torch red and green covered versions (this is not a knock-off setup).

And some stated that using the existing regulator is fine as well when going from acetylene to propane (but not the reverse). I don’t have a problem getting a new regulator if it’s NECESSARY.

I appreciate any thoughts on the conversion.

Thanks!
Sharon in Iowa



Rather than go thru the brain damage and expense of converting to propane, learn how to use your acetylene torch. If you just barely crack open your oxygen valve on the torch, then open the acetylene and light it with an electric striker, you won’t get black uglies. Fooling with the old fashioned striker without oxygen makes black flakes. If you ignite the flame immediately, it burns cleanly. And yes if you change to propane, you get to spend $$ to change.

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Try your acetylene regulator on a propane tank. I doubt it will fit. You will likely need a new propane regulator. The O2 regulator should be OK. You might consider going to a non-adjustable propane regulator for disposable 1 lb. propane tanks. You can also buy refillable 1 lb. tanks that you refill from a 20 lb. grill tank. Finally, you can do away with the O2 tank and regulator completely and look for a refurbished O2 generator from a local medical gas supply place. You will not have to buy O2 after that. The return on this investment is fairly fast, especially for the size O2 tank that you have. There should be a lot in the archives and currently active about this type of setup. The torch, tips and hoses should be fine, but you might consider a set of Paige Tool tips. If you want a real nice, very light weight hose, look at The Tin Man’s website at:

My best advise is take what you have to a local welding supply place, tell them what you want to do and see what they say about it. Good luck…Rob

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Hello Sharon,
There’s lots you could read about propane vs acetylene. Acetylene burns with a reducing flame, but silver is OK with that, whereas platinum is ruined by a reducing flame and you need to use propane for that. Acetylene is much hotter, but the cooler temps of propane may make it easier to use for jewelry work. As I said, you could read reams of stuff about this on various forums. Suffice to say that a lot of jewelry makers prefer propane.
The disposable propane tanks will work for virtually all jewelry needs. The one thing I can think of that would tax them is casting, but for anything that your Little Torch will melt, I think a full disposable tank would give enough propane. Just start with a full tank. Use the partially empty tanks for other work. You could figure all this from the BTU ratings of the LT rosebud tip and the lpm ratings on it, all of which are available in the instructions, but I’m going off what I have read here from people who have melted an ounce or two of metal with an LT.
As far as the regulator, I use a former acetylene regulator on a 1 lb propane tank with no problems. I have an adapter that screws into the regulator and onto the propane tank, but I don’t remember where I got it. I looked at the welding forum on the Hobart welding products website and the consensus there was also that an acetylene regulator would work fine. With any regulator, you need to be aware that the diaphragms are rubber and do not last forever, but they do last a good long time, so I would not worry unless the regulator is very old or show symptoms of not working right. I would not leave a tank open unattended for a long time anyway.
The “T” rated hose is sufficient for acetylene or propane. Again, see welding forum discussions. However, be aware that the LT hose is just a clear plastic hose such as you would buy at an aquarium supply, covered with the fabric sleeve. I don’t believe this is T-rated, which would instead be rubber. I have a clear plastic hose on my Hoke torch because a regular welding hose will not fit, but I’m not really happy about this…when I have time, I will have screw on fittings put on the Hoke and use a T-rated hose. Be aware that the plastic on the LT hose will eventually yellow and become brittle and leak and need replacement. This isn’t a great problem because normally the gas pressure is low and it’s easily turned off, but if you notice the hose is getting brittle it may be time to replace.
If I were you I wouldn’t hesitate to change to a 1 lb propane tank, which is safer than acetylene…just take your setup to a welding supply and they can help you figure out what you will need. As you will know from following recent threads here, changing to an O2 concentrator from the O2 tank is the ultimate in safety for these fuel based torches. HTH, royjohn

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@rmeixner @royjohn This is the info I was looking for… The work I want to accomplish is soldering, annealing, torch enameling, no casting or what might be classified as heavy duty applications.

Here is an adapter sold on Amazon (see pic below). Royjohn, is this the adapter you’re using? Where the regulator faces UP rather than front? The adapter is $15…

I did look at a Propane Regulator ($30) and it appears to be identical to the one I have (without the correct connection of course).

So a flip of the coin, I guess, as to whether buy an adapter for $15 or a new regulator for $30…

There is also a “refill adapter” that hooks to larger tanks for refilling and will work with disposable tanks. I can steal gas from husbands grill :wink:. He doesn’t use it so much anymore.

Can I safely assume that the hoses on the Smith Little Torch are “T” rated? It is an older setup purchased second hand.

Once the swap is complete, what pressures should I start with for the oxy and propane? Once properly set with the acetylene I never touched it and hopefully this will be the same with propane. Just turned it on and off when done.

I have kept an eye out for an oxy concentrator and hope to purchase in the future.

Thx so much for your input. Very much appreciated.
Sharon



:slight_smile: Not sure about the brain damage part, but I did try to get used to it. Sadly I’m both not fast enough and still a little jittery when handling FIRE and the jittery part is compounded when I’m trying to be lightening fast with the lighting of the torch (using electronic strike). $15-30 isn’t all that bad to make the change…
Thx.
Sharon

Hi Sharon,

Yes, that is indeed the adapter I have on my 1 lb tank. Has a little valve on it for shutoff.

I would look around and see if you can get it on ebay for cheaper, but even at this Amazon

price, it would be fine for using with your current regulator and save you $15.

As far as the hose is concerned, the T rating is for rubber hoses and doesn’t apply to the

plastic, cloth covered hose on the LT…AFAIK, that’s what the hose on your LT is…at least

that’s what’s on my older LT model…you could peel back the covering and look, I guess.

I do not have any problem using the plastic hose on my Hoke…it does get stiff as it ages

and eventually brittle. I don’t think there is any easy way to use the T rated hose on your

LT…it is too big in diameter. If you could find someone to weld an adapter on the torch you

could use it, but it would be big and clunky to use with that nice Little Torch…I myself would

just use the hose on the LT with the propane…they sell this torch with the same hose for propane

and acetylene, so it works OK with either.

As far as the settings, each tip has a recommended (max?) pressure of fuel and oxygen. You can

google and find the instructions on line and there will be a little table with the recommended pressures

on it. Mostly you can set the flame by eye, just keeping the pressure low enough to keep the flame from blowing off when you add the oxygen and adjusting the oyxgen to produce the kind of flame you want, being careful not to get too oxidizing a flame (too much hiss). From the max flame length with a particular tip, you can go down to almost nothing…just enough fuel to light the flame…the pressures in

the table are FYI, but you can just adjust as you like…OK, I looked and the psi (both fuel and oxy) for the tips are: tip 2, 2psi, tip 3, 4psi, tip 4, 5psi, tip 5, 6 psi, tip 6, 6 psi, tip 7, 8 psi. I will leave it to you to look up the rosebud tip…

The adapter I have for loading from the 20 lb tank is called a Snozzle and it is available on Ebay. Put the big tank in the sun and the little empty in the freezer, then fill per instructions that come with Snozzle. You get about an 80% fill…you can fill all the way by exhausting the gas with the little relief valve on the 1 lb tank that looks like an air valve, but these get loose after a while, so it isn’t worth it. If you fill the BBQ tank at Uhaul or another filling station, the propane is cheaper than exchanging at the grocery and dirt cheap vs the 1 lb tanks…and even those are only about $3 each. Here endeth what I know about this subject…I think you’ll enjoy the propane and also the concentrator when you get one. -royjohn

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@royjohn

Well that certainly about covers it J. The pressure numbers you found should be pretty easy to remember given they match the tip #’s LOL. Thanks especially for the detailed “what to watch for” instructions. They will come in handy.

I’ll check Ebay for both adapter and Snozzle, thanks for the recommendation.

I misunderstood about the LT hose, thank you for clarifying. I’ll give it a good check over before making the switch and buy new hose if necessary. Sounds like simple plastic hose correctly sized will be fine and less expensive. I can reinstall and figure out the clamping part.

On my way to checking Ebay and placing orders!

Thank you, take care and stay safe!

Sharon

I sympathize with the fear of lighting a torch. I use a rebuilt Invacaire generator. I find it best to allow the oxygen to run through the open line for a moment until you are getting pure O2 and insures you will bleed in pure O2 when you want it. Then I shut down the oxygen and barely crack the propane, light the gas and then bleed in the O2. From then on its a matter of feathering the flame to the shape and heat you want. ( I work as much by the sound of the flame as I do the shape and size.)

Good Luck. I am still messing with that learning curve myself.

Don Meixner

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So I just finished reading a very lengthy post from 2008 on how one should store gas. However there was significantly more information about gas and its dangers! I’ll dream tonight about blowing up the house…:open_mouth: Seriously, I know I should be scared and conscious about what I’m doing and the need to be CAREFUL.

I purchased the adapter for the gauge, a propane refill adapter (FYI they no longer make the Schnozzle), and something I should have gotten when I purchased the acetylene kit… a set of flashback arrestors. I have the leak check liquid from Rio for connections and will also check the tubing for leaks/deterioration. Easy peasy!

So what should I do with the acetylene tank? Is it safe to keep (it’s 3/4 or so full)? I can put it outside on a concrete slab next to the A/C unit (in a vented box?) in case I want to try it again. Empty it somehow? Sell it to someone local?

I so appreciate the information provided here by so many thoughtful and knowledgeable members. It reminds me when I get cocky about something that what I think I know wouldn’t fit on the head of a pin and I should listen to others’ experience and advice.

As usual Thx!
Sharon in Iowa

Judyh is correct. It’s a matter of how you light it. It took me once having black “floaties” all over my studio to figure out that if you crack the oxy along with the acetylene - no more floaties! It doesn’t have to be done with lightning speed - crack the acetylene, crack the oxy (you’ll figure out about how much pretty quickly. Too much oxy and it’ll pop like a little machine gun. Don’t be afraid of it, just cut back on the oxy and try again. It will become second nature to you. I’ve had mine for 30+ years. Prior to that I’ve used them all. Acetylene/air,(Prestolite/Smiths) natural gas/oxy (Hoke torch) etc. when I got my Smiths Little Torch oxy/acetylene.

Oxy/acetylene isn’t “a reducing flame”. The type of flame that you’re using depends on how much oxy you add to the acetylene. Personally I start off with a reducing flame to slowly dry my flow flux and keep my barrier and flow flux from “pulling back”. I increase the size of my flame and go beyond reducing to a hotter flame - but definitely not oxidizing. In a difference of opinion with Jurgen, I have fabricated platinum with my oxy/acetylene torch. It must always be an oxidizing flame. There are many jewelers that solder platinum with oxy/acetylene as well.

I would give it a try prior to switching over. You might be surprised. Play with soldering some scrap together to get the hang of it.

If you do switch to propane remember that when it leaks it pools on the floor. With a 5gal/20lb tank that can be dangerous! Acetylene dissipates into the air and it takes a lot to get to an explosive concentration.

Good luck!

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Thank you @pft1045, I will give it a another try over the next week. So you can open (a crack) both the oxy and gas and THEN light? Judyh also said this, but I didn’t catch it… Sorry @judyh. That was not how I was taught by a local maker. Open acetylene, light, then open oxygen to get your desired flame. I never tried it any other way… Potential danger does not inspire experimentation when alone. FWIW, she wasn’t overly bothered by the soot… But then we were in my studio and she didn’t have to clean it off of EVERYTHING! :slight_smile:

The propane cylinders I plan to use are the 1 lb versions that I’ll refill through a 20 lb tank outside, rather than continue to purchase refills (I have 2 that I’ll rotate). Still a concern, just less of one. I do use a simple MAPP torch for enameling and always check the connection for leaks when I switch out the cylinder.

The information about “reducing flame” and “oxidizing flame” is above my amateur/hobbiest level. I have no professional training other than some private lessons by a trained local maker on the right way to use basic tools, including the oxy/acetylene torch. I just never got the hang of lighting it and the cleanup was very… not fun!

Thank you again,
Sharon

Also, consider the difference in $$$ between propane and acetylene, as well as, the ease and 24/7 accessibility for refills. A typical 5gal20# BBQ tank will last for what seems like a lifetime, especially, if you’re using a "little Torch! After years of using acetylene, I am VERY glad that I switched to propane.

Regarding your intent to refill your 1# tank from a 20# tank, my suggestion is DON’T DO IT!!! That’s an accident waiting to happen!!!

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I’m a retired metals teacher (26 years in high school) - jewelry and ironworking. We used acetylene for years until it was no longer available here. We switched to propane without a look back and it worked fine. Not as hot as acet. but not the potential for carbon contamination. My procedure was to light the gas and then add oxygen. With acetylene the big prank was to light a mixed gas. Done correctly, it results in a Big Bang, like a major firecracker. Propane is tricky enough that the challenge would be to get the right percentage mix or it for it to light. A bit of practice and a good teacher, flame is such an essential part of the process that its worth the effort.

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Hello, Philip,
Of course you’re right about the reducing flame thing…depending on the amount of oxygen added, any fuel gas flame becomes reducing or oxydizing…it’s just that acetylene is a lot dirtier than propane if you don’t watch it carefully, and the reducing flame works well when working on silver…not so much on platinum. Of course, if you’re careful enough…you can work even platinum with it.

Yes, propane will pool at low points and when it mixes enough with air it is then an explosion hazard…on the other hand, acetylene is explosive in mixtures from 2.5% to 82%, so just because it is lighter than air, that does not make it completely safe. All fuel gases must be handled with caution…but you knew that. The absolute safest is the water torch, where the hydrogen and oxygen are only manufactured as needed, and that is the only kind of torch allowed in some shopping malls…that’s the reason some of us have gone to the 1 lb propane tanks…less gas, so less danger. And no oxygen except as needed. -royjohn

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Sharon - no way ever would I fill a propane tank myself. I’ve seen too many explosions. Just light your torch as I recommended with a bit of oxygen on first. I may have over emphasized the speed with which you light it. Just light it. Get an electric striker, they are much easier to use, especially for a beginner. Acetylene is in my opinion and 30 years of experience far safer than propane inside a building.
I started out with a simple plumbers torch. It uses acetylene and ambient air. No floaties ever. It’s a cheap set up and no need for oxygen tanks. I still have it and use for teaching because it’s so darn simple to use and light.
Can’t you find someone close by to help you get started? If you are anywhere near Colorado or want to come visit, I’m happy to help. No charge.

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Building commercial fishing boats and structural wheelchair ramps I burned up a lot of Oxy/Acetylene. I watch BIG torches lit up a lot of ways. You haven’t lived until you have been in the belly of a barge when some New Guy lites up Victor with just the Acetylene on. It fills the air with big black carbon ash bats that you do not want to breathe. And the same will happen in the shop with acetylene without a source for O2 in one form another. In our boatyard we lit the gear by opening the gas and then bleeding in a little O2. How much was experiential. Enough to stop the torch for popping. You learned the right amount quickly. Then shutting the running torch off we alwaysturned off the gas first and then the O2. No floaters that way. In an earlier post regarding lighting up my Little Torch: After clearing the O2 line I said “Shut down the oxygen”. I meant to turn it down, not off. A little unclear, sorry.

Also, I have no fear of air/acetylene in the shop. I switched to mainly propane because the gear takes up little space, it is pretty much universally available, and traveling with acetylene was cumbersome. Also I have trouble holding a Prestolite torch anymore. The Little Torch is easier on my hands.

Don

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Yesterday I was reminded of another reason I don’t like acetylene… It gives me an awful headache… Important to get the torch lit ASAP!

Initially I closed my bezel on the 2nd or 3rd try and I was like “oh, this cracking both to light is not so hard.” Sadly, when I went to solder it onto the back-plate, I couldn’t get it right and it took several more tries… Then once I got it lit the solder wouldn’t flow, so I ended up burning the hell out of my copper piece :slight_smile: . I got most of the stain off and LOS will cover the rest once I finish. I have a difficult time “practicing” with just bits of scrap. I like to make something. If it’s not great I throw it away, but if it turns out OK, that’s a bonus.

I plan to practice some more today, but look forward to trying the propane mix once I get my parts. My electronic igniter is designed for big torch tips so also made the lighting difficult. I’ll try to find the one for small tips, but in the mean time I have an alcohol lamp I can use.

@William6 Thanks for your thoughts. I think today it’s pretty common with the right adapter to refill from a 20 lb tank, but I appreciate the caution. There is also a “refillable propane cylinder kit” made for just this purpose. The refillable cylinder has a fail-safe to keep from overfilling and a stand to hold your 20 lb tank upside-down; made for campers. In lieu of that, using a scale to weigh the cylinder will prevent overfilling. I agree about the expense and availability. I have to drive downtown to get the acetylene tank filled. Don’t like having it in the car for that long :open_mouth: .

Today will be a better day…

@judyh I appreciate your offer… I’m in Iowa so a bit far away. We do have an art center here that offers classes and I was just about ready to sign up and… Covid hit. I did have some instruction when I initially bought the torch but was taught to light fuel then oxy which created the mess and put me off using it. I moved on to other things… Lately I wanted to try again and read about the propane/oxy and here I am. I’m going to continue to work with the acetylene until my parts arrive and if I get it, great… I’ll continue. If not, I’ll hook up the propane and give that a shot. I think I should just practice lighting the damn thing and not worry about the rest :slight_smile: .

@DonMeixner So with propane your process is: Run oxy for a few seconds then turn it way down and crack the propane and light. Got it… Same process as with lighting the acetylene/oxy, yes? Tiny bit oxy, tiny bit fuel, light.

Yes, that’s it. But like all things its still a learning curve. A little O2 for me may or may not be your idea of a little bit. Also I like to use a barbecue grill lighter. My messed up hands have trouble with squeezing a striker anymore.

Don

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