acetylene vs propane

[Andrew R Stewart]

bambuko- I have some concerns about using quick disconnect fittings like shown for O or A gas. My experience with these fittings on the many air lines (fed by a compressor) is that many will develop leaks with use. It's one thing to get a few PSI less in one's tire but it's all together a different possibility to allow a combustible gas and/or a strong oxidizer collect (remember that P will settle onto the floor) with an open flame nearby while one's focus isn't on the floor. Andy

[jclay]

One thing that I lacked when deciding whether to follow the usual torch recomendations here, or whether to stick with what's readily available locally was side by side comparison.
There are plenty of photos of Victor, Harris, Uniweld, Meco, etc, etc but none of them side by side with typical "lightweight" torch in UK.
So here it is (for the UK guys):



As you can see the lightweight shank is almost exactly the same length as Uniweld 71 (freshly arrived from US).
Both knobs are suitably chunky, although Uniweld ones are not colour coded.
Close proxiemity of the knobs on lightweight torch is PITA and often causes propane to be knocked out of adjustment when using oxygen knob (and vice verse).
Uniweld (and similar) torches seem very much better in this regard.
The weight of Uniweld is 185 grams and lightweight torch is 275 grams - not much in it afaic.
The shape of the handles - I've never yet used Uniweld in anger so it will be interesting comparison, specially since I got used to flat handle of my old torch.
Main decider is easy and plentiful availability of fittings - I am finding now how expensive is having to buy everything from US...

One solution is Harris 15-4GB (i.e. old Harris 15-3 with UK fittings. The only such combination available for sale, as far as I know)

As to the act of brazing, I prefer flat torches. Meco Midget, Meco AV-Jet, that sort of thing. No doubt I'd like the feel of the UK torch you posted and I doubt I'd have any issue with the valve placement; I think I'd like it actually. Round torches want to spin in the hand of you hold them by the cylindrical body, which I don't. I moved away from my absolute favorite Meco Midget and back to my original AW1A with 1/4" hose and BB fittings (I grip the torch by the AB adapters which emulates a flat torch and prevents rotation) simply because I needed a cutting head and wanted to minimize the amount of equipment I have. I also like the tool-less tip changes but it wasn't a deciding factor. And having lost two sets of Smith Kevlar hoses to holes I'm a dyed in the wool regular rubber hose guy. No light weight hoses for me ever again. 3/16" T rubber with BB fittings would be my choice if someone stole my 1/4" ones.

At the risk of being labeled a heretic I'll note that I spent WAY too much time in the search for the perfect torch. I think that's a common endeavor. It just doesn't matter much, assuming we aren't talking about crazy huge stuff. I'd be perfectly happy with a larger torch. If I was in the EU I'd be using EU stuff, not going to the expense and trouble to import US iron. None of my torches improved my results. Neither did switching to LP. Spending more time brazing did.

[EricKeller]

I built a decent number of frames with a torch the size of my forearm. So pretty much any torch is the perfect torch. Although I really like the A1WA.

[bambuko]

bambuko- I have some concerns about using quick disconnect fittings like shown for O or A gas...

And that's why I didn't buy airline connectors... but proper propane/oxygen connectors - different design.

[Doug Fattic]

I’ve continued to collect information about propane brazing equipment since I started this thread. This is a kind of recap with a little new information so someone doesn’t have to read the entire thread to get started. Originally I learned how to use propane instead of acetylene because we started to make bicycle frames in Ukraine as a mission project. Then I discovered that my framebuilding class students who lived in bigger cities needed a fuel they could purchase locally and conveniently without being in a business location. Also propane is much cheaper than acetylene. There was also a period of time a few years back when 1 of the 2 acetylene factories in the US closed down for awhile because of an accident and supplies for a bit became scarce. Using propane as a fuel gas with an oxygen concentrator makes a lot of sense for someone starting out.

When I started brazing with propane I used made-for-acetylene equipment using a variety of torch handles. Standard acetylene tips with propane work okay except they can blow out easily from back pressure when the flame is close to the work. It takes just a small puff from your breath to blow out the flame. Next I got made-for-propane mixers, elbows and tips. On the end of the Victor UN-J (on the end of a J-28) and Smith AT-61 mixer/elbow (attached to a AW1A) are threads for a small screw-on tip. These are an improvement. These mixers have bigger gas line holes and the tip ends are recessed to help keep the flame attached to the tip. The best available propane option between the Smith AW1A torch handle and the Victor J-28 or Victor compatible Uniweld 71 is using the Victor UN-J mixer/elbow with their TEN series of tips designed for propane. These take a medium puff of air to blow out their flame. The problem with some of these TEN series of tips (particularly the larger ones like the 3-TEN and 4-TEN) is that the flame pattern can be kind of blunt and not as sharp (I often but not always prefer a thin sharp flame). This depends on who is making them (Victor, Gentec or G-tec). Unfortunately within each brand are better or worse tips for a given size. In other words the Gentec 2-TEN has a better flame pattern than the Victor 2-TEN but the Victor 3-TEN produces a sharper flame than the Gentec 3-TEN. The screw-on tips for the made-for-propane Smith AT-61 mixer elbow are not recessed so they don’t stay attached as readily and blow out more easily and the flame pattern is short and blunt. Smith used to make a series of all-in-one mixer/elbow/tip for the AW1A handle that were designed for propane. These are the AW400 series (AW405, AW407 and AW409). They have a nice sharp flame tip and work great except there isn’t a place to buy them anymore unless you get lucky finding some old probably used ones.

The very best tips for propane are multi-port tips. In the US, these are made by Meco, Paige and G-tec. The side ports around the main orifice stabilize the flame and make them easier to light and much harder to blow out. The flame pattern varies a lot between these 3 brands. My favorites are the Meco tips because the side ports are very small and don’t increase the heat pattern width but stabilize a very sharp pointed center flame. These are my favorite when fillet brazing. It takes a really strong puff of air to blow out these flames. Way more than the recessed tips. The Paige side ports are not round but are slits. They work well but have a little broader heat pattern because there are bigger flames coming out of the side slits. The problem with these Meco and Paige tips is that they only fit the threads on the end of the elbow on a Meco Midget torch handle. The handle is not round but shaped like a cigarette box. Some people prefer this shape but I am with the majority of not liking them. The G-tec multi-port tips have the same threads as Victor tips. The problem with these G-tec tips is that the side holes are fairly large so they act more like a rosebud with a fairly broad heat pattern. This works great in some applications like bi-plane fork crowns where I want a soaking broad heat rather than a pinpoint one. But normally for many situations (especially fillet brazing) I prefer a sharp rather than a broad flame.

So, there is not one perfect combination of torch handle, mixer, elbow and tips (in the US). G-tec makes propane mixers for about every brand of torch handle. Their elbow screws into the mixer and their Victor compatible tips screw onto the elbow. Their elbows come in 3” and 6” lengths. One is a little short and the other a little long (unless using a huge flame) for my taste. I am used to the Smith and Victor 5” long mixer/elbow/tips. The G-tec elbows don’t have quite as sharp a bend either as standard elbows. It is more similar the bend on a Smith AT-61. This means that if you have a Smith AW1A you can use the G-tec mixer on it and whichever length of elbow you prefer with any of the Victor and compatible TEN series of tips. The G-tec propane tips are just like the Victor series except they are made of brass instead of copper. Copper is better because of its ability to withstand heat. For intermediate hobby use it doesn’t really matter.

An important new development is that Paige is making 2 new copper adaptors so their tips (and Meco’s) will fit the Smith AT-61 and Victor UN-J threads. The Meco/Paige tip threads are 1/4” X 28 tpi (teeth per inch). The AT-61 treads are 1/4” X 32 tpi and the UN-J are 5/16” X 27. So their Victor adaptor would have female 5/16” X 27 threads on one end and Meco 1/4” X 28 male threads on the other. The Smith adaptor would be 1/4” X 32 and 1/4” X 28. They are supposed to be available in March. Before it wasn’t possible to use Meco or Paige multi-port tips on a J-28 or AW1A. Well without making an adaptor on a lathe. I modified the Paige MMH adaptor for Hoke torch handles so Meco tips could fit on a Smith AT-61. I cut off the threaded end and bore it out with an end mill and then tapped that hole with 1/4” X 32 threads so it would fit onto the end of the Smith AT-61. That allows me to use my favorite Meco multi-port tips with a Smith AW1A torch handle.

[Paul Jacobs]

I’ve continued to collect information about propane brazing equipment since I started this thread. This is a kind of recap with a little new information so someone doesn’t have to read the entire thread to get started.

This is all really useful, thank you.

[morrisond]

How much Ventilation do you need if you using a Propane set-up in a Garage? Open the side Door? Open the Garage door - but then have to deal with the wind blowing the torch out?

Industrial Air scrubbers needed or you will die from the fumes?

[jclay]

How much Ventilation do you need if you using a Propane set-up in a Garage? Open the side Door? Open the Garage door - but then have to deal with the wind blowing the torch out?

Industrial Air scrubbers needed or you will die from the fumes?

Ventilate the place. Minimally I would have your side and garage doors open enough to support a reliable, gentle air exchange via local winds or with the help of a fan if that's what it takes.

As fuel gasses go I believe that by products of LP combustion aren't nearly as bad as some others. Still, I'd expect some carbon monoxide and that's not a good thing. And remember that the fluxes you're using are at least corrosive so presumably their vapors are; who knows what else is going on with them. Although I doubt (hope) you're not using cadmium based fillers, fumes from molten metal (and the alloys within) aren't real healthy either. If you're using fillers containing cadmium then you need to be serious about reliable, forced evacuation of the fumes from your breathing zone.

For context: This is an exposure based thing. In a full time industrial setting there should be reliable, engineered, serious ventilation. But you're not. Lots of us (self included) have brazed with the workshop all buttoned up and we're still here. But I can smell nasty things and always get a funny taste in my mouth. I don't do that anymore, even for the lone braze-on. I open a couple of windows, fire up my 24" exhaust fan that's built into the opposite wall directly above my brazing station, and throttle the flow (with a shutter outside, on the discharge side of the fan) down to a gentle/adequate rate to exhaust the fumes up and away from me. It works well and the shutter (home made fan door with a cord and cleat for positioning) was a lot less expensive than a variable frequency drive. Photo during shop makeover here: Flickr

[Andrew R Stewart]

Avoid the hard to escape heat plume off the piece. It carries a lot of flux fumes. Flux head won't kill you right away if at all. But it will leave you glad you stopped. Andy

[jclay]

Can steel be welded with LP? I never tried but from what I read on the interweb it sounds like it, at best, doesn't work well in that application. I was recently reminded of how handy it is to be able to OA weld the odd thing, like a framebuilding fixture component that you suddenly need. Flickr

[JohnPell]

Per the below links, oxy-Propane can not be used for gas welding:

Gas Welding – Acetylene vs Propane

[MLReed]

I spoke with Paige Tools last week. They will be coming out with adapters for the common torch handles. These will allow for the use of their tips on A1WA, J-28, Gentec, etc. ETA is sometime in November.

[Doug Fattic]

There have been several times in the past year Paige Tools has optimistically expressed that they were making these adaptors available soon so their propane specific multi-port tips can be used on either Victor J-28 or Smith AW1A torch handles. Unfortunately every deadline they stated has passed without results. This makes me skeptical that they really will be available in November. I don’t doubt they plan on making them eventually but something has always come up to keep them from being available right away. For example I was told back in March they would be available in 2 weeks. Well see this time.

There is an adaptor option available now from TM Technologies that allows Meco and Paige tips to screw onto a Victor UN-J or Smith AT-61 mixer elbow. I just became aware of these this summer. They do require using a sleeve you can buy at hardware stores to braze the adaptor onto the elbow. Their Meco Tip Adaptor part number is AWS-0067 and costs $12. One end has ¼” X 28tpi threading to fit the Meco/Paige tips and the other end is plain ¼” OD brass. This adaptor needs to be brazed onto an elbow with the help of a sleeve that slips over the 2 pieces. These bronze sleeve bearings (which are really just short tube sections) can be bought at most hardware stores under the brand name Hillman or Handi-pack. For a Smith AT-61, use a 5/16” OD sleeve with a ¼” ID that is ¾” long. For the Victor UN-J find one with a 3/8” OD and a ¼” ID that is 1” long. If going the Victor route, this piece must be drilled out half way through with a 5/16” bit. This is because the Victor elbow is 5/16” in diameter (The Smith AT-61 elbow is 1/4” OD). This step you created inside the sleeve (from 1/4” to 5/16”) keeps the pieces from moving while brazing. Some portion of the elbow and maybe part of the adaptor should probably should be cut off so the tip doesn’t stick out too far. Obviously since a Smith elbow and the Meco tip adaptor both have an outside diameter of 1/4” there would not be any need to drill the bronze bushing and it could be used to braze the 2 pieces together just as they all are. It should also be obvious that somebody can make the sleeve the holds the adaptor to the elbow on a lathe instead of buying one.IMG_0448.jpgIMG_0447.jpgIMG_0453.jpg
In this case I have used a Gentec 881W mixer (a clone of the Victor UN-J) and cut off the end threads before brazing the adaptor to the elbow with a bronze sleeve

[MLReed]

There have been several times in the past year Paige Tools has optimistically expressed that they were making these adaptors available soon so their propane specific multi-port tips can be used on either Victor J-28 or Smith AW1A torch handles. Unfortunately every deadline they stated has passed without results. This makes me skeptical that they really will be available in November. I don’t doubt they plan on making them eventually but something has always come up to keep them from being available right away. For example I was told back in March they would be available in 2 weeks. Well see this time.

There is an adaptor option available now from TM Technologies that allows Meco and Paige tips to screw onto a Victor UN-J or Smith AT-61 mixer elbow. I just became aware of these this summer. They do require using a sleeve you can buy at hardware stores to braze the adaptor onto the elbow. Their Meco Tip Adaptor part number is AWS-0067 and costs $12. One end has ¼” X 28tpi threading to fit the Meco/Paige tips and the other end is plain ¼” OD brass. This adaptor needs to be brazed onto an elbow with the help of a sleeve that slips over the 2 pieces. These bronze sleeve bearings (which are really just short tube sections) can be bought at most hardware stores under the brand name Hillman or Handi-pack. For a Smith AT-61, use a 5/16” OD sleeve with a ¼” ID that is ¾” long. For the Victor UN-J find one with a 3/8” OD and a ¼” ID that is 1” long. If going the Victor route, this piece must be drilled out half way through with a 5/16” bit. This is because the Victor elbow is 5/16” in diameter (The Smith AT-61 elbow is 1/4” OD). This step you created inside the sleeve (from 1/4” to 5/16”) keeps the pieces from moving while brazing. Some portion of the elbow and maybe part of the adaptor should probably should be cut off so the tip doesn’t stick out too far. Obviously since a Smith elbow and the Meco tip adaptor both have an outside diameter of 1/4” there would not be any need to drill the bronze bushing and it could be used to braze the 2 pieces together just as they all are. It should also be obvious that somebody can make the sleeve the holds the adaptor to the elbow on a lathe instead of buying one.IMG_0448.jpgIMG_0447.jpgIMG_0453.jpg
In this case I have used a Gentec 881W mixer (a clone of the Victor UN-J) and cut off the end threads before brazing the adaptor to the elbow with a bronze sleeve

Thank you for sharing this. I've been trying to decide if I should wait to buy a Paige adapter or make my own. Based on your input, I am going to make my own.

Do you recommend Meco over Paige tips (for propane)? What would be the best size tip(s) for brazing lugs? It's a lengthy thread - sorry if you already covered this.

[Doug Fattic]

Do you recommend Meco over Paige tips (for propane)? What would be the best size tip(s) for brazing lugs?

That depends. For silver brazing i prefer the Meco tips because they have a stronger center flame without as much side heat coming from the satellite holes. This is especially helpful when cleaning shorelines. For brass brazing I have a tendency to attach the Paige tips because they still have a sharp center flame but the side slits provide some welcome slightly broader heat pattern. Of course others might prefer a different combination.

I usually choose the #4 Meco tip when lug brazing. For my students I find that the #3 works better because its slightly less heat gives them a bit more time to assess what is happening at the joint. When I was brazing a fancy lugged frame I liked a smaller tip better working around the curly cues. It kind of depends on hand eye coordination and speed recognition. The smaller tip requires a bit more defined flame pattern to cover the lug evenly while the bigger tip allows a more general soaking heat a bit further away but necessitates a more instant reaction so the area doesn't over heat. Pick your poison. I have found I use most of the Meco and Paige tip sizes while making a frame. I would get the Paige #2 and Meco #3 if I was forced to reduce my tip inventory. I haven't yet found a use for either of the Paige or Meco # zeros. Remember that the Paige 5 is not the same as a Meco 5. I would guess it is more equal to a Meco 3. It is a bit confusing because the side holes on the Paige put out more flame then the tinier Meco side holes while its center hole is smaller than the Mecos.

[MLReed]

That depends. For silver brazing i prefer the Meco tips because they have a stronger center flame without as much side heat coming from the satellite holes. This is especially helpful when cleaning shorelines. For brass brazing I have a tendency to attach the Paige tips because they still have a sharp center flame but the side slits provide some welcome slightly broader heat pattern. Of course others might prefer a different combination.

I usually choose the #4 Meco tip when lug brazing. For my students I find that the #3 works better because its slightly less heat gives them a bit more time to assess what is happening at the joint. When I was brazing a fancy lugged frame I liked a smaller tip better working around the curly cues. It kind of depends on hand eye coordination and speed recognition. The smaller tip requires a bit more defined flame pattern to cover the lug evenly while the bigger tip allows a more general soaking heat a bit further away but necessitates a more instant reaction so the area doesn't over heat. Pick your poison. I have found I use most of the Meco and Paige tip sizes while making a frame. I would get the Paige #2 and Meco #3 if I was forced to reduce my tip inventory. I haven't yet found a use for either of the Paige or Meco # zeros. Remember that the Paige 5 is not the same as a Meco 5. I would guess it is more equal to a Meco 3. It is a bit confusing because the side holes on the Paige put out more flame then the tinier Meco side holes while its center hole is smaller than the Mecos.

Thanks, Doug. Much appreciated.

[Doug Fattic]

Here is a quick review of the advantages/disadvantages of various tips for propane so one doesn’t have to read through many back pages. There have been new developments since this subject thread began.

It is possible that one can use whatever torch/mixer/elbow/tips that they were using for acetylene to be used with propane. It works but just not as well as stuff designed specifically for propane. The main problem is that the flame is harder to light and will go out easier. This is especially so if the flame is close to the work (like when fillet brazing) and the gas pressure bounce back extinguishes the flame. It takes only a small puff of breath to blow out a propane flame from acetylene equipment.

Victor makes the TEN series of tips designed for propane. These special screw-on tips with recessed ends (they have a slightly bigger counterbore on the end of the tip) helps keep the flame attached to the tip. This is one of the challenges of using propane. One has to adjust the volume controls a little more carefully to keep the flame where it belongs. These recessed end tips have to be attached to a mixer/elbow that fits on the end of the torch handle that is also designed for propane use. Propane requires a higher oxygen to fuel ratio than acetylene. Therefore the Victor UN-J mixer elbow has larger and more numerous holes on the oxygen side. Smith also makes the AT-61 propane specific mixer/elbow that accepts screw-on tips. Unfortunately the Smith screw-on tips for the AT-61 are not recessed and so do not preform as well with propane as the Victor TEN tips. It takes a more powerful puff of air to blow out a flame on a TEN tip. Gentec and G-tec (2 separate companies not related to each other) also make Victor TEN tip clones. Their threading and orifice sizes are the same as Victor made TEN tips but they vary in materials and overall size.

TM Technologies makes multi-port tips for the Meco Midget torch that is an improvement over the TEN series of tips when using propane. The holes that surround the center hole stabilize the flame even more than one on the TEN series of tips. In other words tiny flames surround the big flame. It takes a very strong puff of breath to blow out a multi-port propane frame. Page Tools also makes multi-port tips for propane (and natural gas). Their tips are marketed for use in the jewelry trade. As a result their series of tips have smaller orifices than Meco tips. The side holes are not round holes but rather slits. This effects the flame pattern and they put out a bit more side heat. They are also a bit longer in overall length to provide a better fuel/oxygen mix. For many applications I prefer a Meco tip in the larger sizes (that Paige doesn’t offer) but sometimes when brazing dropouts I like the flame pattern of a Paige tip a little more (even though there is not that much difference between them). Translation: I prefer Meco tips when silver brazing and cleaning shorelines and Paige tips when using brass for fillet brazing and doing dropouts.

The problem with using these superior multi-port tips is that their 1/4” X 28tpi treading is not compatible with either Victor’s 5/16” X 27tpi or Smith’s 1/4” X 32tpi threading. This is where the adaptor that TM Technologies sells can be brazed onto a UN-J or a AT-61 mixer/elbow (with the help of a sleeve) so that multi-port tips can be used with either Victor or Smith equipment to get the best results.

[eMcK]

Oxygen generator came from craigslist for $150, still covered in medical supply company warnings and stickers. When I first turned it on the smell of stale cigarette smoke was overwhelming. It faded after a few uses.

I can't remember where it came from, but I had a Victor 50-10 medium duty torch kicking around. After some research, I realized it was an alternative fuel set up and I purchased a couple of 1390-N alternative fuel tips to go with the small rosebud tip that was already on there.

I've been messing around building some janky trophies for an underground race and some shelving brackets.

It can be tricky to get the O2 setting correct using the flowmeter on the concentrator, but the real issue I am running into is the lack of stead delivery rate from the concentrator. As the machine cycles, the flame shape changes as the 02 ratio fluctuates. This makes heat control on small items very difficult. It get better as the machine "warms up", but it never completly goes away. Is it possible to regulate the flow better?

I'm also having a hard time seeing the metal color compared to the O/A set up I was using. I'm using #3 green glasses, but I can't see much color change without lifting them up. There seems to be a lot more orange flame around the blue with propane.

Thanks for this thread, it was very helpful getting my stuff together. Doug, we met years ago on a train to Portland with the Bilenky crew, I hope all is well with you.

-Eric McKeegan

[EricKeller]

#3 glasses are pretty dark, I use ACE with #2 . I also have some didymium glasses. They would be better with some shade, so I don't use them. I heard the most recent batch of combo ACE glasses were defective somehow and aren't available right now.

[William Chitham]

It can be tricky to get the O2 setting correct using the flowmeter on the concentrator, but the real issue I am running into is the lack of stead delivery rate from the concentrator. As the machine cycles, the flame shape changes as the 02 ratio fluctuates. This makes heat control on small items very difficult. It get better as the machine "warms up", but it never completly goes away. Is it possible to regulate the flow better?-Eric McKeegan

That sounds like the same problem I had with a second hand concentrator. After dismantling the machine and convincincing myself that the compressor, valves and filters were in good order I hit the web and found some info suggesting that the oxygen separating granules (zeolite pellets) in the cylinders can degrade in time and are also succeptable to humidity so now I think that it isn't the flow rate but the purity of oxygen that fluctuates. The easiest solution is to replace the cartridges containing the pellets which I understand is strightforward with the common medical type units but unfortunately my machine was made by a now defunct German company and I haven't tracked down a source of spare parts so I'm back on the bottle for now.

William.