acetylene vs propane

[Alistair]

Larry, the NE series of tips are NOT recessed. They just have bigger orifices than the LT series. They are too big for the way I like to braze most joints. Are you using the AT-61 mixer/elbow? That is designed specifically for Propane while the similar AT-60 is for acetylene. They look alike but the AT-61 has bigger and more numerous holes in the mixing part that carries the gas to the tip.

Doug Fattic.
Niles, Michigan

Doug,

this is only tangentially related to what you wrote above, but I'm hoping you can answer my question anyway.

I got a run of Victor -TEN tips for my propane set up, they work great. I got sizes 2 through 5, plus a multi port mini rosebud. Having played around with the different size tips for a bit now, I realize that there are times where a size 1 or even 0 would be handy.

I tried to buy those sizes from Weldingsupply.com, where I bought the ones that I have already, but they sent me back a PDF of the page in the Victor catalog that shows that Victor no longer (if they ever did) offers a -TEN tip in a size smaller than a No.2.

That being the case, I figured I could either buy the Acetylene specific -TE tips (available in the sizes that I want) and modify them for Propane use, or go with the Gentec, Propane specific tips, which I see are available from Torchtools.com.


Just wondering if you have an opinion on what is the best way to go here?

Thanks,


Alistair.

[Doug Fattic]

Alistair, I took my Victor TEN #0 and #1 tips over to Ukraine and left them there. I didn’t notice if they were Victor or Gentec since they are interchangeable (but not exactly the same). That Victor doesn’t make them anymore is news to me. I agree that you might like to get the smaller ones. I discovered that I liked the #1 even better for fillet brazing than the #2 and for some braze-ons the #0. I’ve started to change tips more often for different jobs. Tip preference is related to personal opinion. It is easy enough to use almost any tip for almost any purpose but I started to get more specific.

I haven’t tried any of the rosebud tips yet and want to try one. Which one did you get? I’ll order one of those when I also order a #0 and #1 for my shop here in the States.

Doug Fattic
Niles, Michigan

[Alistair]

Alistair, I took my Victor TEN #0 and #1 tips over to Ukraine and left them there. I didn’t notice if they were Victor or Gentec since they are interchangeable (but not exactly the same). That Victor doesn’t make them anymore is news to me. I agree that you might like to get the smaller ones. I discovered that I liked the #1 even better for fillet brazing than the #2 and for some braze-ons the #0. I’ve started to change tips more often for different jobs. Tip preference is related to personal opinion. It is easy enough to use almost any tip for almost any purpose but I started to get more specific.

I haven’t tried any of the rosebud tips yet and want to try one. Which one did you get? I’ll order one of those when I also order a #0 and #1 for my shop here in the States.

Doug Fattic
Niles, Michigan

Hmmm, if you know of a source for the Victor brand 1-TEN and the 0-TEN I'd be all ears. I got my Victor #-TEN tips from weldingsupply.com, https://weldingsupply.com/cgi-bin/br....pl?SIGNOUT::1 their website is a little funky to navigate, as I'm sure you know.

The multi port tip I got is the 6-TEMF. If you follow the link above, and type in "6-TEMF" into the search field in the top left hand corner it'll bring up a page that has the -TE, -TEN, and -TEMF tips. If you notice, they list a 0-TEN, but no 1-TEN, then 2 thru 5. When I asked them how come no 1-TEN was listed they replied with an attached Victor catalog sheet saying that those tips only start at 2-TEN. The 0 that they list is a typo, they said they were going to remove it from the website.

Anyway, a while back I had called Victor and spoke to one of their engineers about the multi port tips. He walked me through some flow calcs (using data that is NOT on their website or available to the public, or so he said) and determined that the 6-TEMF was enough of an increase in BTU output over the 5-TEN that it was worth getting. I plan to use it for fork crowns.

Hope that helps.

and thanks,


Alistair.

[Larry]

Thought I'd post a update. I ended up swapping out the tip to the NE153 and bumping up the propane to 10 psi. My machine does display lpm but percentage of flow, which was set at 20.

Here's a quick video of the flame. As the concentrator is going thru it's cycle it's changing the characteristics of the flame. I may have missed it but I don't recall this being mentioned previously.

Doug thanks again for all the help.

[Jim Gourgoutis]

Here's a quick video of the flame. As the concentrator is going thru it's cycle it's changing the characteristics of the flame. I may have missed it but I don't recall this being mentioned previously.

That's unusual. Once the O2 concentration settles down/after the machine warms up, my oxycon doesn't cause the torch flame to fluctuate. My machine -- an older Puritan Bennett -- has an internal holding tank with a small regulator, which likely smooths out any pulsations due to the machine's cycle. On a lampworkers' forum, I've read of some folks making an external O2 holding tank -- if your machine doesn't have an internal tank, that might be something worth looking into. If it does have an internal tank, and you're running your machine at full flow, you might try turning that down a bit, too -- you might be emptying the reservoir tank too quickly, draining it between the pulses of the machine's cycle.

[Larry]

Jim

Thanks for the reply. I wanted to do some testing and relay that information to my concentrator manufacture before I posted back here. But answer your question it does have a small holding tank on the back of the machine. I should have a bit more information this evening.

[Davey Smalley]

I've been in touch with Tin Man and discovered the TM tech light weight hoses and Meco torches are available in the UK from a company called GPE scientific.

GPE Scientific

They are also selling barb to US B size fittings so you can attach the light weight hoses to UK 6mm ID hose.
The company has also got some adaptors to go from UK BSP to US UNF made by a local engineering firm although they're incredibly expensive.

[MrkiMedo]

Another place that seems to carry some BSPP to other threads converter is www.airsupplies.co.uk This one is from BSPT to NPT, but I did not have energy to find BSPP to UNF, their web does not seem to be easiest one to search so maybe a call to them would be more efficient.

[rjtedge@gmail.com]

Hi, I'm just getting my setup all ready to start to learn. I'm going to go with Oxy Propane because of this thread and the ease and price in Australia. I'm a bit confused with some of the equipment though and hoped the experts on this forum could help me out. I've got a Cigweld Comet 3 blowtorch (like this COMET 3 Blowpipe - Cigweld ) and a mixer and hoses for either acetylene or propane.

However it seems that Cigweld only has two choices for welding/brazing elbows for propane, size 8 or a size 15 (COMET Welding Tip Oxy/LPG 554 Size 8). This seems like different sizing than what is referred to in the US, any tips on what I should be using for a lugged frame?

Cheers!

[Doug Fattic]

However it seems that Cigweld only has two choices for welding/brazing elbows for propane, size 8 or a size 15 (COMET Welding Tip Oxy/LPG 554 Size 8). This seems like different sizing than what is referred to in the US, any tips on what I should be using for a lugged frame?

Robert, Cigweld uses a very logical tip numbering system. If you place a decimal one number over from the right, it represents its orifice size diameter in millimeters. So a Cig size 15 tip has an orifice size of 1.5mm. This is almost the same size as a Victor #3 tip. That is a great general purpose size for building bicycle frames with propane. A Cig size 8 has a .8mm hole. That one is pretty small and might be useful for braze-ons or doing rack fillets.

Doug Fattic
Niles, Michigan

[waterlaz]

I've seen a few times people use propane regulators with two gauges. As far as I understand one gauge is for input pressure and the other is for output.
This is rather confusing to me. I am sure that the pressure inside a tank does not depend on the amount of propane in it and only depends on the temperature.
So why the second gauge?

[Doug Fattic]

I've seen a few times people use propane regulators with two gauges. As far as I understand one gauge is for input pressure and the other is for output.
This is rather confusing to me. I am sure that the pressure inside a tank does not depend on the amount of propane in it and only depends on the temperature.
So why the second gauge?

Evengly, probably because they are adapting an acetylene regulator for propane use. If the regulator was attached to an acetylene tank, the gauge would tell you how much acetylene is left in the tank. As you pointed out the pressure in a propane tank remains constant until the very end so it does’t let you know how soon it will run out. Well except it will start to dip a bit near the end.

This was frustrating to me at first, I was used to an acetylene regulator and could tell at any time how full or empty it was. I did buy a gauge from Walmart designed for BBQ tanks that is supposed to indicate propane levels but it isn’t very accurate so I took it off because it made my regulator stick out much farther.

The real way to tell how much propane is left in a tank is to weigh it. However a BBQ propane tank lasts so long (almost a year after making many frames in my case) I don’t bother checking it on a scale very often because the grocery store where I get the exchange is only a couple of blocks away and is open almost all hours.

Doug Fattic
Niles, Michigan

[Larry]

Just to follow up with this I finally gave in and bought a small bottle of oxygen. Things seem to be working as they should and I don't have any issues over heating things. Plenty of chard braze on right now. One day I may eventually send mine in to sort it out, but for now I'm happy.

[jclay]

How to Properly Light, Adjust and Shut Down an Oxy–Acetylene Torch | The Harris Products Group

Harris recommends turning oxygen first as well.

I have seen a few places that say to do fuel first, but that seems to go against the manufacturer recommendations.

I have been wondering why we get the pop when turning fuel off first; what was the mechanism and should I care? Tonight I stumbled into some new information; oxy/acetylene flame propagation speed increases as the oxygen concentration is increased beyond a neutral setting. The claim of the writer was that the increased flame speed causes the flame front to travel into the tip prior to being eventually extinguished for lack of adequate oxygen. I don't understand why extinguishing the flame within the tip would cause a pop (hot gas envelope collapsing or some such, perhaps) but a Linde publication verified a doubling of combustion speed as the oxy/acetylene concentration rose from 1:1 (6 m/s) to 2:1 (12 m/s) before dropping to 10 m/s at 3:1. I didn't find authoritative verification of flame retreat into the tip but for some reason I tend to believe it. And that leaves me at this: Combustion within my torch tips is not something I want to encourage. Until I hear something that seems to make more sense, I am an oxygen off first guy.

[waterlaz]

The claim of the writer was that the increased flame speed causes the flame front to travel into the tip prior to being eventually extinguished for lack of adequate oxygen. I don't understand why extinguishing the flame within the tip would cause a pop (hot gas envelope collapsing or some such, perhaps) but a Linde publication verified a doubling of combustion speed as the oxy/acetylene concentration rose from 1:1 (6 m/s) to 2:1 (12 m/s) before dropping to 10 m/s at 3:1.

That's what I've been told about flame travel. It causes a pop because the end of the tip is relatively small compared to the inside of the tip. So when the flame enters the inside, lots of gases burn very fast and can't exit the tip. This builds up high pressure.

[jclay]

I said the lack of adequate oxygen was the cause of combustion loss as the fuel was turned off. I meant to say fuel but I just realized that I don't really know what the mechanism is. Does the mixture become so fuel lean that it won't burn, does the flame front go charging upstream until it encounters the mixer and the segregated oxy and fuel feedstreams, making combustion impossible, or is waterlaz on the right track wrt the expanding gasses causing much higher flow stream speeds, ejecting the flame front back out of the tip orifice and extinguishing it? The latter mechanism seems to make the most sense to me, right now anyway.

I don't know the answer, but it does seem reasonable to think that the flame front enters the tip when the fuel is turned off first. That's all I need to know.

[Will Neide]

I have been wondering why we get the pop when turning fuel off first; what was the mechanism and should I care? Tonight I stumbled into some new information; oxy/acetylene flame propagation speed increases as the oxygen concentration is increased beyond a neutral setting. The claim of the writer was that the increased flame speed causes the flame front to travel into the tip prior to being eventually extinguished for lack of adequate oxygen. I don't understand why extinguishing the flame within the tip would cause a pop (hot gas envelope collapsing or some such, perhaps) but a Linde publication verified a doubling of combustion speed as the oxy/acetylene concentration rose from 1:1 (6 m/s) to 2:1 (12 m/s) before dropping to 10 m/s at 3:1. I didn't find authoritative verification of flame retreat into the tip but for some reason I tend to believe it. And that leaves me at this: Combustion within my torch tips is not something I want to encourage. Until I hear something that seems to make more sense, I am an oxygen off first guy.

Found this little video interesting. His controlled shutdowns are always oxygen off first, but he does extinguish the flame a few times to show what happens when you open the oxygen too far.

[jclay]

Have any of you used the AT605 acetylene rosebud (for the AW1A) with LP? I'm curious to know if works at all, and if so, how well.

Thanks

[turpentine]

PSA:

There is an invacare oxygen concentrator at Rytel International in Cincinnati for $99. It looks like it works.
I got mine for $85 just by calling and being nice. If you call they will probably cut you a deal. Shipping is just market.
(513) 561-1200
seems pretty cheap compared to going rate on craigslist etc and they seemed to not have any problem with shipping them since they are a big company with a big warehouse.
They also said they could get more if people wanted them.

[ThomD]

I've been using the TM Tech propane set-ups since they came out, and do everything with propane. Main reason was keeping the shop clean, and the greater safety of working with propane, where at least all the stuff is legal to own and transport in a non-industrial setting, where I live. At the time there were also some writers arguing that it made for cleaner welds, but that doesn't really make much sense. You can't black a piece of metal with it though.

TMT has the rose heads for their torches, and they will fit them to other torches also, not sure if that would make the neck useless for other brands though.