Finding the best torch handle and tips to work with propane

[Ahmdo Molah]

... I just tried last night my Meco Midget torch handle with a Meco #5 tip last night using one of my Devilbiss 5lph concentrators to supply the oxygen. It works fine even when I switched to a larger Paige MX tip. ...

That seems to perhaps negate the comments by 'surlypud'(Chris?) in post #11 of the thread 'Propane and propane related accessories' (https://www.velocipedesalon.com/foru...ies-35064.html) mentioning how the combination of a Midget's smaller diameter mixer + oxygen concentrators' limited output pressure can cause a lack of O2 supply issue when a large flame is desired.

If you recall that meeting with 'surlypud', I'd appreciate YOUR clarification about what the problem was in his case.

[Doug Fattic]

That seems to perhaps negate the comments by 'surlypud'(Chris?) in post #11 of the thread 'Propane and propane related accessories' (https://www.velocipedesalon.com/foru...ies-35064.html) mentioning how the combination of a Midget's smaller diameter mixer + oxygen concentrators' limited output pressure can cause a lack of O2 supply issue when a large flame is desired.

If you recall that meeting with 'surlypud', I'd appreciate YOUR clarification about what the problem was in his case.

It was 8 years ago I met with surlypud so I don't remember the details except it was a nice visit.

I did go to the shop this morning and again tried my Meco Midget with a Meco #5 tip as well as a Paige MX tip using my Devilbiss 515 concentrator. That combination worked fine but the restriction of the oxygen supply through the torch handle and elbow only allowed the flame to be at about a middle setting. When I put the same tips on my Uniweld 71 torch handle with a UN-J mixer/elbow, I could turn up the oxygen to a greater volume than I could with the Midget. The Uniweld allowed for a greater volume of oxygen flow through its bigger holes and as a result provided a more powerful flame using the same tips.

A Meco Midget torch handle is pretty small. I suppose it was designed for the jewelry trade. To make it bigger to my liking, I added A size flashback arrestors to the bottom of the handle so it fit my hand more comfortably. They are pretty expensive at around $70 a pair. The elbow screws onto the top of the handle and has a pretty small ID.

In the same way, 5 lpm concentrators can not only put out more or less volume but they can also vary at how pure of oxygen they are putting out too. My Invacare concentrators work fine but my Devilbiss 515 and 525 concentrators put out a greater volume of oxygen. Concentrators to keep grandma alive should produce around 92% + - oxygen. I have a Devilbiss 525 model that puts out around 80% that works fine with all my tips.

[Ahmdo Molah]

...

I did go to the shop this morning and again tried my Meco Midget with a Meco #5 tip as well as a Paige MX tip using my Devilbiss 515 concentrator. That combination worked fine but the restriction of the oxygen supply through the torch handle and elbow only allowed the flame to be at about a middle setting. When I put the same tips on my Uniweld 71 torch handle with a UN-J mixer/elbow, I could turn up the oxygen to a greater volume than I could with the Midget. The Uniweld allowed for a greater volume of oxygen flow through its bigger holes and as a result provided a more powerful flame using the same tips.

A Meco Midget torch handle is pretty small. ... The elbow screws onto the top of the handle and has a pretty small ID.

In the same way, 5 lpm concentrators can not only put out more or less volume but they can also vary at how pure of oxygen they are putting out too. My Invacare concentrators work fine but my Devilbiss 515 and 525 concentrators put out a greater volume of oxygen. Concentrators to keep grandma alive should produce around 92% + - oxygen. I have a Devilbiss 525 model that puts out around 80% that works fine with all my tips.

Thanks Doug for the reassuring clarification. So it's not just the mixer(handle) but also the relatively smaller ID of the Midget's elbow that contributes to the 'bottle neck effect' when used with an oxygen concentrator instead of a high pressure O2 tank. I'm comfortably reassured with my leanings towards the Smith AW1A torch and AT61 mixer for use with an oxygen concentrator.

The Kroeber Aeroplus 5 oxygen concentrator I'm keeping an eye out for is a 5lpm unit with a max output pressure of 70kPa (10psi) and O2 concentration range of 95%(-3%) - 85%(+/-3%) depending on the output setting, so it should be sufficient if I can score one in decent used condition for a reasonable price. At least there is a small yet steady circulation of them in the 'dog boomer' scene.

[acorn]

Anyone ever heard of National Torch? They aren’t as big as Victor, Smith, or Harris, but they make several torches for acetylene, propane, and other fuel gases. And they are made in Minnesota. They even have torches that use a fuel gas + air compressor instead of oxygen.

Here are a few of their torch offerings
https://nationaltorch.com/?page_id=178

The torch I was looking at is the National Torch 3B-B. Looks like maybe a stouter, shorter size compared to the Smith AW1A or Victor J-28. I’m not sure if their tips are compatible the Smith or Victor torch elbows, or if the Meco or Paige tips are compatible with National torch elbows. However, it does appear that they also make multi-orifice tips that fit their own torch.

Anybody heard of these guys? What do you think? Their 3B-B torch looks like it’s nicely made. And they do seem to have good product support by showing their full specs for both their standard propane tips and multi-orifice tips.
https://nationaltorch.com/wp-content...vised-2018.pdf

Oh, I did a search on YouTube and I found a video of someone using what looks like the National 3B-B torchI mentioned above. He connected it to an oxygen concentrator and it seems to work fine. Maybe this would work for lugs and fillet brazing?

[Ahmdo Molah]

Thanks to those here (especially Doug and John), I've been brazing with my compact "mobile" setup.

[O2 Concentrator & Butane Brazing Setup Full (B)]

O2 Concentrator & Butane Brazing Setup Full (B).jpg

- DeVilbiss 515 oxygen concentrator (Rebuilt w/ heat exchanger & moisture separator)
- Smith AW1A & AT61 w/Paige Tools NK Adaptor & Meco(TM Technologies) OX Tips 2,3,4,5
- TM Technologies Ultra Lightweight Hose
- Western Enterprises WE-63 Check Valves(torch side) & FA-230-P Flashback Arrestor(regulator side)
- Uniweld RVT8011 Dual-Stage Acetylene Regulator (with stainless steel diaphragms)
- Adjustable Mic Stand to raise hose level and minimize weight on torch hand.
- Longfian JAY-120 Oxygen Analyzer and T-Shaped Relief Valve*
* Connected along output of O2 concentrator via a T-shaped relief valve, for real-time monitoring or O2 concentration as well as pressure relief setup prior to O2 shutoff.

[T-Shaped Relief Valve]

T-Shaped Relief Valve.jpg

When the lever is fully down(vertical), O2 is directed to the O2 analyzer. When the lever is horizontal, O2 flows left to right and eventually upward to the ultra lightweight hose.
Before shutting off the O2 at the torch, the valve's lever can be set half open/closed. This prevents pressure stress in the O2 concentrator (resulting in alarms if functioning).

- Custom made* 'Butane Canister To Regulator Adaptor & Support Chassis'

[Torch, Butane-Regulator Chassis]

Torch, Butane-Regulator Chassis.jpg

* The adapter I mentioned in post #68 had quality issues and worse customer service, so I had to make my own. I was able to source locally a brass CGA 510(female) to BPT(1/4) male adaptor so I made my own.

[Butane Torch Nozzle Cutaway-Mod For Regulator Adaptor]

Butane Torch Nozzle Cutaway-Mod For Regulator Adaptor.jpg

The Adaptor's valve is sourced from a 'butane-air torch' with the nozzle and most of the elbow cut off, using just the valve/socket assembly and the short remainder of the elbow's aluminum pipe. This short pipe section is connected to a compression fitting with a male BPT(1/8) opposite end, then a dual female BPT(1/8 to 1/4) adaptor fitting which receives a male BPT(1/4) to CGA510 female socket. The sealant used is Loctite 592 with Loctite 7649 primer(needed for the 'non-reactive' aluminum pipe, and general speed up of cure time of the 592 sealant).

The Support Chassis is made with aluminum angle, and the regulator's support is one half of an old PC power supply enclosure. The modeling was done in 3D CAD.

[Support Chassis]

Support Chassis.jpg

[nspace]

Thanks to Doug's advice over the years, I've had a little propane brazing setup for quote some time with a bbq tank and oxygen concentrator. I haven't really had the time to go full tilt into a full frame between 2 kids, and a demanding job and barely finding time to ride. But over the holidays I am taking on a little project to restore an older 4130 29er mtb frame I have in order to make it more useful (think dirt tourer/commuter/picnic bike with a basket).

I fired up the torch yesterday to remove the hose guides (they are routed along the top of the tube, and are a very terrible design) so I plan to braze on some new ones on the under side of the TT.

Attaching some pics of the results and also a pic of my flame. The flame definitely has a hiss to it, and I can get a sharp inner cone, but I've suspect maybe this flame is too hot? Most of the stuff I've found with respect to flame characteristics and what to watch for is with acetylene. Any tips from what you can see in the photos?

I'd like to dial in the flame and do some more practice before I braze the new guides on. I plan to use System 48 filler to add some hose guides and also some hour-glass style rack mounts to the frame and fork.

After braze-on removed. Used some flux to try and protect the tube. I also used a technique I saw in a Paul Brodie video to use a wire brush to get off some of the


Flame:


Video of dialing in the flame (this is with a 2-TEN tip)
https://www.flickr.com/photos/193440...posted-public/

Stripped frame with all 4 braze-ons removed

[nspace]

Little update from my frame modification project. I managed to get the hose guides brazed on. It's been a while since I have done anything with the torch!

It's probably been about 7 years since I last did anything like this so I felt like I was relearning some stuff: I should have probably controlled the torch with my dominant hand for greater accuracy and added filler with the other. It's so easy to add too much filler or get things too hot but I managed to avoid exhausting the flux. I used a 2-Ten tip—I think this worked out ok. I tried to get the cone in tight to keep the heat centered around just the area I needed the filler.

Here's my Fattic inspired setup with the Tinman Tech lightweight hoses and Uniweld 71 torch:


I used 1/8" round stock and some twisted electrical wires to keep the guides aligned along the top tube. Pretty low-tech and fiddly to setup, but it worked!


I used System 48 filler and Stainless Light Flux. I probably added too much filler in some cases, a little goes a long way. I had to file it down on one guide because I essentially made a fillet that didn't look too nice on a hose guide:


Up close, post-braze:


All done. In a few areas the filler maybe wetted out a little more than it needed to. But not lumpy or detectable with my fingers after a couple s



Next I need to add 1 or 2 more to the under side of the seat stay, and then I am going to move onto some hourglass-style rack mounts on the front fork.