acetylene vs propane

[Ryan Christbaum]

Thanks for all of this information, Doug. Very useful.

Because of this thread, I bought a propane elbow and some tips for my Smith A1WA. I chuckle to myself thinking of the run on used oxygen concentrators by frame builders, but it sure makes sense from a safety and convenience point. Just to be safe, I decided to buy the proper rated hose for all fuels, so I got a length of the regular rubber type and a kevlar section. If feels rather flimsy, but the kevlar hose is awesome at the torch end and I highly recommend it. Unfortunately (but not unexpectedly), my attempt to practice a joint with propane felt like trying to write left-handed. The fillet was okay and seems plenty solid, but didn't look as nice as I can normally pull off w/ acetylene.

I need to re-read this thread to fine-tune the flame I'm using (and practice), but I didn't really have much trouble with lighting the flame or keeping it lit. If nothing else, price and convenience of LP makes me want to pursue this as an alternative to acetylene. The addition of the concentrator being useful for either fuel does seem like a smart alternative to a high-pressure bottle, so maybe in the near future.

[David Tollefson]

Question on oxygen concentrators and "time" on the machine. I'm looking at a local used unit on CL, Respironics Millenium Model 605, 5 Lpm, seller says has most likely 36000 hours on it total, but only 500 since refurbished. Is this inordinately high? Anything to be concerned about?

[veryredbike]

Dunno about 36000 but 500 is nothing at all. These machines are meant to run 24-7 for years. If it's cheap and it's just been refurbished like that, I'd say go for it.

One thing to check: PSI. If it's 5 lpm at 5psi you won't be able to put a flashback arrestor on the oxy line. Most of the glass folks think it's unnecessary since the pressure is low and there isn't a ticking bomb on the other end of the hose. You'd still want to use it on the fuel, of course. That being said, if you can find one that'll do 10psi it might give you some extra (possibly unnecessary) peace of mind by letting you use that arrestor and a bit more versatility with larger tips.

Edit: It's also worth noting that you can get better flow by removing the heppa filter. You don't want to let it actually go above the rated 5lpm... but you can use the extra juice to compensate for a longer hose, etc.

[David Tollefson]

Thanks! Picking it up today...

[David Tollefson]

Question on hose compatibility with propane -- R type okay?

[shirk]

Question on hose compatibility with propane -- R type okay?

T- grade hose is needed to work with propane.

[David Tollefson]

T- grade hose is needed to work with propane.

Needed, or just better? What's the difference and long-term issues?

[Will Neide]

Needed, or just better? What's the difference and long-term issues?

I THINK you'd be fine very short term with R, but long term you want T. I think the R will rot out and crack. No bueno.

[David Tollefson]

I can off-load the R I just bought...

Grade T on the way... Thanks!

[nspace]

What a fantastic thread. After reading this thread over and over I am finally in the process of trying to collect some of the gear. Some of the stuff is difficult to find in Canada so I may have to ship to the border and take a drive down to pick it up in Buffalo, NY. This thread is a great resource! Thanks especially to Doug.

[nspace]

Thanks again for the wonderful advice in this thread. Just started purchasing a few basic things to get started. I purchased the Uniweld/Ameriflame torch, Gentec check valves with B fittings, Grade T hose with B-fittings, Gentec 881W mixer and TEN2 and TEN3 recessed propane tips. I haven't hooked up the propane tank yet. The oxygen concentrator is a Healthdyne Alliance 505, and the B hose fits right onto it, which was nice. I did not install a flashback arrestor on the oxygen but have one installed between the hose and the fuel regulator.

Here is the one thing I need to solve however. I must have got the wrong check valves, or I am missing an adaptor. I bought the B-size fittings from Torchtools, which fit the hose perfect, but they are too large for the smaller fittings on the torch end. Did I order the wrong size check valves? Is it an A size that I need at the torch end?

Photos:

11934648865_0a87dea4b6_z.jpg 11935486956_d539dd7e96_z.jpg

[Alistair]

Yep,

female A to male B, https://www.tinmantech.com/html/weld...e_adapters.php

Alistair.

[nspace]

Thanks! I will either grab some of those or try to hunt one of those Kevlar AB hoses if I can find someone no asking for a fortune to ship to Canada!

[nspace]

Finally got everything I need, hope to get things up and running this weekend. I know this was touched on before, but I couldn't find a conclusive answer.

I have B-size check valves between my heavier T-hose, and lighter TM Tech hose, similar to how Doug described. I'm working on setting up the oxygen line now and checking for leaks. When I fire up the oxygen concentrator, I can't get any O2 flow out of my torch head. When I remove the check valve, it is smooth sailing and I have a lot of range. Seems like the check valve is reducing all flow. Is anyone using their concentrator without a check valve, or is there some type of lower pressure check valve I should be looking for?

Edit: UGHHHH Nevermind, found my problem. When it built pressure in the line, air was escaping somewhere else and pressure didn't build probably to get past the check valve. I opened the concentrator up. There seems to be a few plastic fittings in this. I found air escaping from one brass fitting...only to go to tighten it to find its connected to a plastic fitting and the fitting snapped with 0 effort... Seems like some of the plastic on this ancient concentrator has deteriorated. Now I have to find a replacement piece, and somehow get this plastic fitting that has snapped off out it. Well this has been fun :)

[Doug Fattic]

Seems like the check valve is reducing all flow. Is anyone using their concentrator without a check valve, or is there some type of lower pressure check valve I should be looking for?

I don't think it is essential to have a flashback arrestor (which stops a flame) before the oxygen concentrator because it is not a container of lots of highly pressurized gas. I do have a flashback arrestor in the propane line. I also have small "A" size check valves (which stops gas going backwards) right on the end of the torch handle without any issues of oxygen flow from the concentrator. Their weight is so small I don't notice they are there. While common sense tells me it isn't needed when using a concentrator I am not an expert in gas safety that knows for sure.

[nspace]

Thanks Doug! I read your point about the flashback earlier, so I don't have one of those. Just the check valve. To your point, I read somewhere that most of the concentrators have built in check valves...but there is really no way of me knowing, so I'll make every effort to use one at this point.

When I ran the machine with the plastic shell taken off with the check valve on, I could hear air escaping somewhere. I waved my hand around and found a connector where air was escaping. I guess the plastic had deteriorated and was leaking. I'm hoping I can extract the broken bit of plastic from this brass fitting, and find a new 3/8" brass coupling and repair it. Then I think my problem will be solved and hopefully it will work with the check valve! Off to the hardware store to find some screw extractors!

[nspace]

Whoohoo! Got everything running and fired up the torch, it is working perfect (as far as my new eyes can tell).


I don't know if this is valuable to anyone but I'll share some of the things I discovered in the event someone stumbles across this with the same problem. Since some of these oxygen concentrators on the used market, this experience was a reminder that sometimes plastic gets weaker over time. The one I have is a Healthdyne Alliance 505 and from some of the dates I've seen on this thing, it must be from around 1999. When I first setup connected the oxygen lines I found a leak coming from a hairline crack in the plastic 9/16" thread that the B-hose was connected to. It was irreparable, so I had to open up the machine and add a new connection with a reversed barbed fitting. That is attached to the clear tubing that you see above.

Once I got that solved I couldn't build enough pressure in the system to get the air flowing past the check valve. I could hear air escaping somewhere. I opened up the unit and discovered the plastic had again started leaking at a brass/plastic fitting on top of one of the tanks. Of course when I tried to gently tighten it, the fitting just snapped with hardly any force. I had to put the fitting in a vice, and use a screw extractor to get it out. Once out, I added new 1/4" brass fitting with some teflon tape (since this was threading into another plastic fitting on the tank, I didn't want to tighten this anymore than I needed to). Once I reconnected that, I had no problems with the check valve and everything worked great.

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All connected again:

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Future changes...this works fine, but I will probably take Doug's advice and put 2 A sized check valves at the torch and eliminate them at the transition between my hoses.

Also a couple things I discovered in regards to purchasing the gear from Doug's list:

- Map out connections between male and female ends in regards to flow direction through arrestors/check valves

- TM Tech hoses have 2 female ends, and come with a separate brass B to A reducing coupler. Unfortunately the B size end is female, so if you want to connect it to your check valves, flashback arrestors or B-hoses directly, you will either need to make sure you have a male end on one of them, or in my case I bought a Male-Male B-sized connector.

These probably aren't big setbacks, but I had a hard time finding any of this stuff locally where I am in Canada, so most of it was ordered online and it sucks when you need to wait another 1-2 weeks for a single set of brass couplings to arrive.

12415472315_3068efb068_c.jpg

Going down to to Buffalo, NY tomorrow to pick up my order from CycleDesignUSA, then I can start putting flame to metal.

[MrkiMedo]

Hello!

Currently I am running propane + 5L oxy bottle:

160sysz.jpg

2aaijvo.jpg

I will haveto move hoses up as Doug advises. Torch handle is Yildiz, turkish copy of Gloor 3601. Tips are Gloor for propane.

I have choosed 5L bottle so that I can carry it on my bike, still it is not fun to drive it around. But, now I have spotted DeVilbiss 5 Liter Oxygen Concentrator, on local classifieds, what an luck!

Doug, is this the concetrator you are using? 5 Liter Oxygen Concentrator - DeVilbiss Healthcare

[Doug Fattic]

Doug, is this the concetrator you are using? 5 Liter Oxygen Concentrator - DeVilbiss Healthcare

Mine is an older model. I have a refurbished DeVilbiss model 515. It works great. As I understand it from their advertising, the newer models are quieter but I haven't had any chance to examine one myself. Mine is a bit noisy but not irritatingly so. It's like white background noise.

[nspace]

I finally fired up the torch and did my first test brazing this weekend with the oxygen/propane setup. The torch worked fantastic. I'm having so much fun with this. I'm starting out using the Cycle Design USA Stainless Light Flux, and System 48 filler. Between Doug's advise on here, and my phone calls with Wade at Cycle Design USA, there has been a wealth of information to take in. Wade was nice enough to send me a bunch of sample tubes and lugs which has been keeping me busy between practicing mitres and and now using the torch. I also made use of his pin kit which seems to work really well.

On my first test (just a ring of steel onto a tube), it worked fairly well, and it looks like I got penetration through most of the joint and also exhausted the flux at the end.

12892535995_2d373fc40b_z.jpg

After that I tried to improve heat control and tried a seat tube lug. I didn't cover the entire lug with flux and end up scorching quite a bit of it...I was focusing the flus with the silver would be flowing but in retrospect I think anything that will be getting heated should be covered? I don't have a photo after the seat lug is done, but you can see the area I didn't put flux on in this photo. My apologies for my dollar store shades. I bought some brazing shades, but the shade 5 lens were too dark to really see what I was doing so I resorted to these.
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After that I tried a HT lug. I got decent penetration through most of it, but definitely cooked things too hot towards the end. I am assuming I either had too much heat, or just didn't work fast enough.
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Next up I did a BB/ST join. In my unprofessional opinion this one went lightyears better than the other. I heated everything up evenly until the flux turned clear, and rather than continuously going around the joint to try and keep it hot (which I think was exhausting the flux too quickly), I started working in sections and keeping the torch a little bit ahead of where I was adding filler. This definitely seemed to help avoid scorching the flux. From everywhere that I can see, around all shorelines and on the end of the tube inside the lug, there is silver everywhere. The one thing that still sucks is my shorelines. I didn't end up with any gobs of silver falling down the tube so at least it was the tube melting the filler and not the flame, but I definitely added too much. Is this just a feel thing...to know how much filler to use? Sometimes I found it a bit hard to tell when the silver gets pulled all the way through but maybe I just need to develop a finer eye to it.

With flux (also should have coated the entire BB, and I could definitely see the advantages of joining more than one tube in there area as I improve).

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After brazing, there were a couple of small scorch marks where the flux turned black on the tube, but nothing that would impede the silver from flowing into the joint.
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After soak with a bit of filing (removed the pin) and emery cloth. My shorelines aren't so good.
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Inside the lug, it's hard to see, but it looks like the silver got everywhere around the tube.
12892933645_e4e78aff3a_z.jpg

I would say the day was a success. I definitely made some mistakes (as I expected), but felt like I learned a lot just from finally doing it, and the results seemed to improve towards the end. I've never done this before and I've only sweat soldered copper pipe once in my life, so lots more practice is ahead.

Are there any hints for achieving better shorelines? If there is anything wrong I am doing, that you can tell from the photos, any feedback or suggestions would be greatly appreciated. I seemed to go through a lot of flux, so I'm not sure if I am using too much or if that is normal.

Thanks!
Tom