acetylene vs propane

[waterlaz]

Is there any alternative to the TM technologies lightweight hose? My flashback arrestors and my torch have a metric thread M16x1.5. And since the TM technologies hose is pretty expensive, I'd want to get something that realy fits. Perhaps there is a hose without any connectors?

[jclay]

Is there any alternative to the TM technologies lightweight hose? My flashback arrestors and my torch have a metric thread M16x1.5. And since the TM technologies hose is pretty expensive, I'd want to get something that realy fits. Perhaps there is a hose without any connectors?

You'll find differing perspectives on hoses and torches here. For me, I no longer consider lightweight hoses to be worth their expense or fragility. I use regular hoses as shown in the attached photo; half the cost, twice the length, far more durable than the two sets of Smith lightweight hoses coiled up on the rope I used to keep them off of the floor while brazing; one has a hole from a spark. It's highly unlikely that I'll replace them. I've gotten to like the big hoses.

image.jpg

[Doug Fattic]

My recommendations for torches and hoses comes from teaching students that have a wide range of abilities how to braze. I see how some students that are not particularly talented have trouble catching on. Their hands struggle to do what they should. Heavier torches and hoses that resist moving exaggerate their somewhat clumsy motions. This creates frustration and they can get discouraged – obstacles to doing extra practice to get over the hump. The less talented are the ones most helped with lighter equipment. Those with lots of coordination will do well with whatever. In any case no matter one’s talents, it is very nice to use an airline torch with light hoses. I love mine. YMMV. The downside is cost and availability convenience.

It is human nature that a person isn’t likely to go to extra effort to get the very best options if an all-in-one okay welding package is available – particularly if it is cheaper. Most people want to focus on building frames instead of locating equipment. Those combo units don’t tend to come with flashback arrestors or check valves however because the manufacturer’s purpose is to sell based on low price and convenience and not safety.

When I was in Ukraine in October, Evgeniy (waterlaz) rode his bike to visit our shop a couple of times. James from Poland (duggyballs) was also able to come and stay for a few days. They were able to try out our J-28 torch with TM hoses. Fortunately both had lots of talent and some experience so they could braze very well without much correction from me. It was fun to have both of them around for a bit as I taught Yuriy how to build transportation frames. I’m guessing Evgeniy might be considering lighter hoses based on his exposure to them in our shop since he already has access to other equipment. I switched from using Smith Kevlar hoses in Ukraine to the light TM hoses because they are more durable even though they aren’t quite as light as Kevlar hoses. They don’t resist motion nearly as much as standard rubber hoses.

Evgeniy, I suspect TM Technologies is using some kind of industrial hose already commercially available for some other purpose. My guess is that they just attach “A” size fittings. I asked once at a general hose supply store if something they had could be used for brazing. They demanded more information than I had so I didn’t explore it any further.

Doug Fattic
Niles, Michigan

[LoHiFab]

wonderful thread as noted many times.

I'm on the fence between a propane/oxy brazing set up and just getting a TIG welder. I have enough welding experience that I know the learning curve will be very steep so I am not too worried about that aspect. The price difference between the two isn't a big concern to me either.

One big concern is that all my other frame building activities take place in my small unfinished basement. I'd be happy to weld down there but don't like the thought of the open flame and flammable gases in my basement. The solution would be to move the brazing operation to my detached garage but I can't store any of the stuff there so that's a lot of back and forth anytime I need to do a little joining.

Thoughts or peoples experience would be appreciated.

[waterlaz]

Thank you. I guess I'll keep looking for some flexible hoses. It's not realy in my top list of things to get, just something that would be nice to have.

[waterlaz]

One big concern is that all my other frame building activities take place in my small unfinished basement. I'd be happy to weld down there but don't like the thought of the open flame and flammable gases in my basement. The solution would be to move the brazing operation to my detached garage but I can't store any of the stuff there so that's a lot of back and forth anytime I need to do a little joining.
Thoughts or peoples experience would be appreciated.

I wouldn't worry about propane much. Here in Ukraine there are hundreds of thousands of people who use big(50 litres) propane tanks in their kitchens(indoors) and accidents is something VERY rare.
You should be perfectly safe as long as you are careful.

[David Tollefson]

I'd be more concerned about venting than the flame.

[willemcycles]

Hi Doug, many thanks for the clear description of your oxy propane setup with concentrator,
question: does the oxy hose from concentrator to torch need a flashback arrestor? or can it be an enforced 1/4" hose from concentrator all the way to a barb/femaleB connector on the torch side? I can't seem to find a cheap devilbiss like you have, will a 5lpm with 5.5 psi output philips do as well, the devilbiss has 9psi output. Thanks in advance

Check and see if the plastic barb thing can unscrew from a brass fitting on your concentrator. It did on my DeVilbis. That brass fitting is 9/16" X 18tpi that is actually a B hose fitting. If your barb is a permanent attachment to the concentrator then you need to create a connector hose – probably out of that clear tubing it was designed to connect to in the first place. Welding supply houses carry a bass fitting that has a barb on one end and a B fitting on the other. Or you can get a plastic one like I unscrewed from my DeVilbis. Jam the clear hose (or whatever is convenient) between the 2 barbs. Now you have your connector hose. Next you connect the the hose that connects to your torch handle to the connector hose you created with a flashback arrestor. The pressure in the hose is so slight I doubt a hose clamp is need to keep it on the barb.

I'm not sure of the accuracy of this but it appears the ID of a 3/16" welding hose is 4mm and the ID of a 1/4" hose is 5mm. These are too small to fit onto the end of my plastic barb which the first rib is 6mm and the last rib is 10mm. In other words I don't think you can cut off the fitting on the end of a welding hose and jam it onto the plastic barb on your concentrator.

The problem with the Smith NE propane tips that attachs to the propane AT61 mixer elbow is that they are way bigger than what I would advise someone starting out to get. I ordered a set from Cyberweld and the only one they sent me was the NE153 which has an orifice size of .086". The smallest NE tip is the NE151 at .070" diameter. It also doesn't have the recessed hole in the tip to help keep the flame attached. In Ukraine I use the AW207 (.055") and it works fine with propane. But because it is designed for acetylene it doesn't have that recessed tip. I would advise a Victor size 2 tip (.o46") for propane when one is starting out. It is possible that the Smith LT104 tip (.047") that is designed to fit onto the acetylene AT60 mixer elbow will also fit onto the AT61.

[William Chitham]

This may seem like a dumb question but when shutting down an oxy propane torch which do you turn off first - oxgen or propane? Or doesn't it matter? I have seen both in instructional vids and texts.

[Will Neide]

This may seem like a dumb question but when shutting down an oxy propane torch which do you turn off first - oxgen or propane? Or doesn't it matter? I have seen both in instructional vids and texts.

To turn off: Turn off oxygen first.

To turn on: Propane first.

You don't want pure oxygen to burn.

[willemcycles]

Hi did this list work out for you? (except for the regulator instead of torch side arrestor) than I'm buying the same stuff, many thanks, willem

Alright, this is what I'm thinking of getting myself. There's a place locally that sells a couple oxygen concetrators per month on craigslist for $150ish. I'm going to keep my eyes on it... no blinking.

3/16 - T Grade Oxy-Fuel A-B Twin Hose [TH316-T-AB] - $33.96 : Arc-Zone.com, The Welding Accessory Experts
Hose $55

Gentec FlashBack Arrestors FA5TPR Pair, Oxy - Fuel, Torch-End Flashback Arrestors
FBA $44

Amazon.com: Ameriflame R361-510 Heavy Duty Single Stage LP Gas Regulator with CGA510 Inlet: Home Improvement
Regulator $53.99

Ameriflame MD71TH 6-Inch Light Duty Welding Handle for General Purpose Heating, Brazing, Welding and Other Flame Processes - Amazon.com
Torch $39.00

Resever Cylinder Adapter
Adapter for camp cylinders $22

GENTEC 171W Welding Brazing Tips sizes 000-6, equivalent to VICTOR W-J
tip 2: $26

NU-CALGON Leak Detector, High Viscosity, -20 To 220F - AC Refrigeration Accessories - 2RZW4|4183-24 - Grainger Industrial Supply
leak detector $15

[Dmoeny]

I'll let the owner of the above set-up comment on how it worked, but interject one thought.
If you want to use disposable cylinders, you might want to consider a regulator with a regular acetylene fitting (cga 200) and the Uniweld FV600 Oxy/Fuel Adapter. This gives you a shutoff at the point of the cylinder, instead of having to unscrew the cylinder from the regulator to cut gas flow.

regulator:
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1


Disposable adapter:
http://www.amazon.com/gp/product/B00...?ie=UTF8&psc=1

[bambuko]

To turn off: Turn off oxygen first.
To turn on: Propane first.
You don't want pure oxygen to burn.

That's interesting... I was always taught to turn off by shutting off fuel gas first?

[Alistair]

To turn off: Turn off oxygen first.

To turn on: Propane first.

You don't want pure oxygen to burn.

Oxygen is an oxidizer, not a fuel. It can't burn by itself. If you turn off the fuel first, then the oxygen will blow out any residual flame, preventing it from travelling back down the hose.


Alistair.

[William Chitham]

Oxygen is an oxidizer, not a fuel. It can't burn by itself. If you turn off the fuel first, then the oxygen will blow out any residual flame, preventing it from travelling back down the hose.


Alistair.

Thanks guys, just starting out with oxy-fuel and trying to learn good habits but it's tricky when you see flat out contradictory advice about something so fundemental. The fuel off first sequence
makes sense to me so I'm going with that. I've been reading a "Safe Use of Oxy Fuel Guide" produced in the UK by Murex ( http://www.murexwelding.co.uk/gb/en/...f-Oxy-Fuel.pdf). Are there any other "bibles" anyone might recommend for general oxy-fuel safety technique?

[ljm]

Oxygen is an oxidizer, not a fuel. It can't burn by itself. If you turn off the fuel first, then the oxygen will blow out any residual flame, preventing it from travelling back down the hose.

True, but many materials, including those used in welding hoses etc, will readily burn in pure O2.

[Alistair]

True, but many materials, including those used in welding hoses etc, will readily burn in pure O2.

Sure, if your hoses are on fire adding O2 won't be good...


Alistair.

[jclay]

True, but many materials, including those used in welding hoses etc, will readily burn in pure O2.

Your welding hoses won't without an ignition source. 100% oxygen, absent ignition, won't cause your hoses to combust.

[Will Neide]

According to Victor, you shut off the oxygen first.

The Keys to Oxy-Fuel Safety : Safety in the Welding Shop is Everyone’s Responsibility

Shut down:

Regardless of fuel gas used, always shut down the oxygen first and the fuel last. This technique leak checks both valves every time the torch is shut down. A snap or a pop indicates a leaking oxygen valve, while a small flame at the end of the tip indicates a fuel gas leak.

[Will Neide]

I stole this from here: O/A: why shut off acetylene first? [Archive] - WeldingWeb™ - Welding forum for pros and enthusiasts

VICTOR A THERMADYNE Company

September 29, 2003

Re: Shutdown Procedure for Oxy/fuel Cutting Torches

To Whom It May Concern:

Victor Equipment Company recommends a shutdown procedure for oxy/fuel torches that is
different to that recommended by most other manufacturers of gas welding and cutting
apparatus. There are times when this difference in procedure may cause confusion and
concern. From this, the following is an explanation behind the logic of our procedure.
Victor recommends turning off the oxygen first, then the fuel when shutting down an oxy/fuel
torch. The primary reason for this procedural sequence is SAFETY. This can best be
explained with the following three reasons:

1. One of the most common causes of backfire and sustained backfire (burning inside
the torch) is overheating of the tip or nozzle. The primary cause of overheating is
insufficient flow (velocity) of gases which allows the >5000° F flame to burn on the
surface of the tip or even slightly inside the preheat orifice(s). Proper gas flow with
sufficient velocity causes the flame to burn slightly away from the tip end.
One of the simplest ways of determining adequate fuel flow when using acetylene is
to have a “soot free” flame when the fuel is on and no oxygen is flowing. Thus, if the
operator turns off the oxygen first, and the flame produces soot, he is reminded that
insufficient flow was used. From this, the operator should either increase the flow or
change to a smaller size tip. (This depends on the application.)

2. All valves have the potential of leaking at one time or another. When the fuel is
turned off first, the flame is immediately extinguished, even though there might be a
small fuel gas leak. If the oxygen valve is closed first, the flame will continue to burn
(hopefully without soot!). Then, when the fuel valve is closed, and if a leak is present,
a small flame will continue to burn. This will immediately warn the operator of a
problem.
Neither shutdown procedure will show an oxygen leak, but at least in the latter
method, the operator can detect the more hazardous of the two.

3. As mentioned, other manufacturers recommend closing the fuel first, and then the
oxygen EXCEPT when there is a sustained backfire (burning inside the torch). In
this case, they recommend immediately closing the oxygen valve first.
Humans are creatures of habit. To recommend reversing the shutdown procedure in
an emergency situation would be like telling an automobile driver to use his right
foot on the brake for normal stops, but in the event of an accident, use the left foot. A
few seconds can mark the difference between a safe shutdown and a damaged
torch, and most importantly, possible injury to the operator.
There have been claims that using our method causes soot build-up inside the torch.
Victor has performed many tests and found that the soot build-up that others claim to occur is caused by improper gas flow and pressure settings, not the sequence of closing the valves. This holds true for all equipment that we have tested.
It should also be noted that all industry standards organizations, such as ANSI, AWS,CGA, and NFPA, recommend the operator follow the manufacturer’s instructions for proper operation of the equipment. To this extent, there’s not a “golden rule” in the industry. Since there are basically two different ways of shutting down an oxy/fuel torch, we feel our method provides the safest way.

Sincerely,

David Pryor
Manager, Product Technology and Advancement