acetylene vs propane

[afwalker]

Shiggy,
I picked up the Uniweld 71 handle for $35 to do better than the TM Tech Meco Midget I already have. I like the super small midget, I've build a few bikes with it but would like a bit more heat sometimes, like with forks.
I plan to use Acetylene not Propane with it, so all the tips Doug mentions are for propane, except the all fuel ones he mentions. You probably picked up on that.
I'll get tips like the 17-1 and 17-0 for the higher heat, a rosebud too would be nice.
I pay $50 or so the get refilled tanks on Oxy/Acetylene for the B size 40CF tank. I can build 4 or 5 bikes on that tank. I don't think I'll bother with a bigger tank, seems ok for now unless I really start building more bikes.
cheers
andy walker

[dsaul]

I just set up a Oxy/Propane torch using some of Doug's recommendations and came up with the following:

Uniweld 71 torch handle - $35 at Amazon
Gentec G17-3 mixer and tip - this is Gentec's equivalent to a UN-J mixer and Victor TEN3 tip - $48 at Torchtools.com
Ameriflame R361-510 propane regulator - $55 at Amazon
Devilbiss 525 O2 concentrator- Bought used with 2000hrs on it at DotMed.com for $188 shipped
Smith Kevlar AB fitting hose set - $65 from Cyberweld
Propane tank - borrowed from barbecue grill

I've only used it a few times, but it works well and the O2 concentrator provides plenty of oxygen flow. The oxygen flow is a bit irregular for the first minute or so after you turn the machine on, but smooths out by the time I'm done pre heating the joint.

Dave Saul

[Straz]

I'm in the process of purchasing the components for an Oxy/Propane setup and have really enjoyed this thread. I picked up a used Invacare Platinum XL concentrator over the weekend. It has a barbed fitting for the output. How are people connecting hoses and flame arrestors to these units?

Also, it sounds like people are leaning towards the J-28 and it's clones over the Smith AW1A. Is that due to the availabilty of tips for propane? In my web search, it seams that the Smith propane tips are hard to come by.

[EricKeller]

Cyberweld has the Smith AT61 and NE tips for a reasonable price. I didn't see which size tip to buy in this thread though. The tips are only $10

[Doug Fattic]

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.

[devlin]

I love this thread so much. Thanks Doug and other contributors.

[cardinal-creative]

Great thread with a lot of info. A google search will return pages of hits for oxy/propane cutting, but almost nothing for brazing.

I've been using a Smith medium duty outfit (toughcut) for my brazing needs. I chose a standard oxy/acetylene outfit and added a T-grade hose. Acetylene regulators work fine with propane and I aimed to keep everything cross-platform in case I found the need to switch to acetylene. I modified the mw205 tip for propane by recessing the outlet slightly (approximately twice the factory hole diameter and deep enough to form a slight cup). I swapped emails with Smith about the difference between their acetylene and propane tips and ultimately the only difference is the tip recess. For the A1WA, their response was "We only have the propane welding tips for the MW and SW. You can look at the at61 tube and mixer with the ne153 bullet tips for propane."

The larger handle is a bit bulky for simple braze on work and unfortunately the most comfortable balance point is where the hoses meet the body which leads to bumping the gas valves. The Uniweld 71 handle is on standby for when I can gather the mixer/tips/hose.

[suhacycles]

Heard about sportscaster Hannah Storm and her recent accident with her propane grill. She's lucky compared to what coulda happened. Any tips on using an oxy/propane setup indoors where space and ventilation isn't great?
Stay safe ya'll...

[Andrew R Stewart]

Ideally a vent fan with a duct that pulled from the floor would be a good thing. And the fan should be sparkless. My shop has a fan pulling from waist high and another from the ceiling. But I don't use Propane. Andy.

[devlin]

OK. Trying to find oxy concentrators locally in Australia. Saw this on ebay........

UPDATED NEW OXYGEN GENERATOR CONCENTRATOR ADJUSTABLE OXYGEN 90% r3 | eBay

Is this going to be suitable? From the numbers they advertise it seems like it will work. Finding it difficult to find lower priced units elsewhere, even 2nd hand medical suppliers.

Also looking at this torch kit as well. Any thoughts?

eBay Australia: Buy new & used fashion, electronics & home d

[shirk]

Thank you Doug for your info in this thread.

I was going to go with Oxy/Acetylene for my noob first set up but will instead go oxy/propane with concentrator.

[Proparc]

Doug Fattic, I just want to say tanks, (yes-that was on purpose)on this one. I have respiratory problems and acetylene bothers me no end. Great, great info-again thanks,( I didn't repeat the pun).

[shirk]

If anyone was looking for the Uniweld 71 torch, Amazon has it for $35 with free shipping.

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

These are back in-stock and available if anyone is looking.

Not long after the link was posted with $35 they were sold out. Back up now at $40.99.

I just bought one.

Oh and fyi Amazon won't ship these to Canada, I had to use a shipping service in Blaine WA for this.

[Mark Walberg]

These are back in-stock and available if anyone is looking.

Not long after the link was posted with $35 they were sold out. Back up now at $40.99.

I just bought one.

Oh and fyi Amazon won't ship these to Canada, I had to use a shipping service in Blaine WA for this.

Say, it looks like my Victor welding tips will screw right on that Uniweld handle. Does anyone know if they do, indeed, fit?
-Mark Walberg

[Doug Fattic]

Say, it looks like my Victor welding tips will screw right on that Uniweld handle. Does anyone know if they do, indeed, fit?
-Mark Walberg

Yes, Victor J series tips (both the ones Victor makes as well as Gentec clones) fit the Uniweld 71 handle. I have tried them together and it works fine.

Doug

[dbohemian]

Doug Fattic, I just want to say tanks, (yes-that was on purpose)on this one. I have respiratory problems and acetylene bothers me no end. Great, great info-again thanks,( I didn't repeat the pun).

I am confused how Acetylene could cause you respiratory issues because when it is burned correctly the only by-products produces are CO2 and H2O. Is it that you are creating quite a bit of soot when you light? You do not have to do that BTW. If your regs are set correctly you should be able to light the torch with no soot. As somebody also mentioned above propane is almost every bit as dangerous as Acetylene, more so in some ways so it is not a alternative to not taking care of any combustible fuel.

[EricKeller]

after many years of starting at a flowrate that produced soot, I found out that's the wrong amount of acetylene anyway. However, I suspect even a clean flame has unburnt components in it. Not sure which would cause alergies though.

[Doug Fattic]

I was in the shop this week playing with tip combinations to use with propane and my oxygen concentrator. I recently ordered some more from Smith and Victor to complete my collection. I examined them closely to see what differences there might be between those designed for acetylene and propane. I’ll comment on the Smith tips first.

The sole propane specific mixer/elbow Smith now makes for its AW1A torch handle is the AT61. This is part of their Versa Torch system in which very small tips with different size orifices can be screwed onto the very end of what they call their brazing tip assembly (which is the mixer base and elbow tube coming out of the torch handle). This makes changing tip sizes easier and cheaper than when the whole mixer/elbow/tip is an all one unit like the AW series of tips (which doesn’t mean I like them better). There are 5 small screw-on tips that are labeled for propane use (NE151 to NE156) that screw onto the AT61. The problem for framebuilders is that these tips are larger than what we would commonly use – especially for beginners. Smith also has a similar AT60 treaded tip tube for acetylene. There are 4 small screw-on tips with part numbers starting at LT103 and going to LT106 that are made to attach to the AT60. Even though these tips are designated for acetylene, they are the size we commonly use with propane making frames. They also screw onto the end of the AT61 and work with propane just fine. I’m going to chuck them in my lathe to drill the recess tip like Victor does so the flame stays attached better. This recess should be twice the size of the orifice and of the same depth as its width. The LT and NE series of tips are all the same except for their orifice size.

The propane AT61 mixer has more and bigger holes on its bottom for the fuel to make its way to the tip than the AT60 designed specifically for acetylene. Smith used to make what they call a brazing tip assembly for propane like the AW205 (which is for acetylene). One needs to change this whole all in one unit to change orifice size and not just the end tip. They were designated with a 4 instead of a 2 after the W. For example the AW405 was for propane and the AW205 is for acetylene. The last number changes depending on its orifice size. They no longer make the AW400 series for the AW1A torch handle but they might still be found used.

The AW61 + tip is shorter before and after the bend than an AW series tube. This shorter extension requires a bit more wrist motion to flick the flame off of a joint for heat control. The AW61 doesn’t have as much bend either. It requires I keep the handle a little more horizontal than vertical to keep the flame perpendicular to the tube by bending my wrist. It is preferable to keep the wrist straighter if possible like when holding on to handlebars. These 2 differences aren’t much of a big deal but I can notice them. The stem of an AW series mixer/tip is also longer keeping the heat of the joint further away from the torch handle. This only becomes an issue if brazing goes on for some time.

I like that the Smith AW1A handle is chrome plated and its knobs have only 4 bumps around their circumference. My fingers don’t rest against points with that arraignment. Its shorter body length (compared to other “airline” torch handles) is not a problem for my hand. The Smith mixers have a nice knurled section that screws into the handle that makes it possible to swap them using only your hand. They appear more substantially made than the Victors – which need to be attached with some kind of wrench.

So to review the best combination for framebuilding with propane using the Smith AW1A torch handle is the AT61 mixer/elbow with the LT series of tips (even though they are designated for use with acetylene). The disadvantage of not having a recessed tip that helps keep the flame attached can be remedied by drilling it in a lathe (or not). I would recommend the LT104 size of tip for general use including fillet brazing. Its hole is .047” in diameter. For doing heavier pieces like fork crowns or bottom bracket shells you would probably prefer a bigger tip like the LT105. Actually, when you get experienced, you can use even bigger ones. I like using the AW series of torch tips because they have a longer section after the bend and the bend has a greater more comfortable angle to it. So when I’m using acetylene I prefer an AW203 or 205 over an AT60 + LT tip. An AW207 tip actually works with propane (I’ve used that combination constantly in Ukraine). But I don’t know what the engineering reasons are for the larger capacity fuel holes in the AT61 compared to the AT60 or AWs. I’d be interested hearing from those that might know. I’ll comment on Victor propane specific tips in another post.

[veryredbike]

So, I'm turning 30 next month and my parents have decided that they really want to treat me to something nice... I was thinking about a torch kit, but my relationship with my landlord isn't great... and his relatives live in a house that shares our yard. So, yeah.. I figure that an oxy/acet setup would probably be over the line. Now "this thing is just like your BBQ grill, and this other thing doesn't store any gas", that I think I could talk my way around.

That being said, portability would be good. Has anyone tried those little "fill at home" bottles that folks who need these medically hook up to the concentrator? Seems like I'd need a regulator that fit it, but that otherwise it should work. That being said, they're tiny... would they last me a couple hours of work on a bike? More than that doesn't matter... I can just hook it back up and fill it for the next time... but yeah, curious about that. Is the volume too low to provide proper flow?

Last question: is this something I can use outside? I know that it's not ideal, but that it can be made to work fine with acetylene (I'm looking at you, Andy!), but the talk of the flame not wanting to "stick" to the torch made me wonder about this.

Thanks all!

Jim

[veryredbike]

So, I'm turning 30 next month and my parents have decided that they really want to treat me to something nice... I was thinking about a torch kit, but my relationship with my landlord isn't great... and his relatives live in a house that shares our yard. So, yeah.. I figure that an oxy/acet setup would probably be over the line. Now "this thing is just like your BBQ grill, and this other thing doesn't store any gas", that I think I could talk my way around.

That being said, portability would be good. Has anyone tried those little "fill at home" bottles that folks who need these medically hook up to the concentrator? Seems like I'd need a regulator that fit it, but that otherwise it should work. That being said, they're tiny... would they last me a couple hours of work on a bike? More than that doesn't matter... I can just hook it back up and fill it for the next time... but yeah, curious about that. Is the volume too low to provide proper flow?

Last question: is this something I can use outside? I know that it's not ideal, but that it can be made to work fine with acetylene (I'm looking at you, Andy!), but the talk of the flame not wanting to "stick" to the torch made me wonder about this.

Thanks all!

Jim

Nix that oxygen bottle question, because in retrospect I think it's silly. I just got excited looking at all of the ways to do this.

Real questions:

1) If I want to use this somewhere where there isn't really a good place to store propane tanks... will I get any life out of the small tanks used for fully hand-held propane torches (like for plumbing work)? Was considering trying it at work, but yeah, nowhere to safely store a bbq size tank. I could easily bring smaller tanks in though.

2) It says that the back-check valves can be optional... what is the potential harm of not having them?

3) Expansion on the back yard brazing mentioned above: if it's possible to do this outside, will I need a big wind barrier, or will doing it near a tall fence suffice in normal weather?

Thanks, reading through this has been great!