Flame welder buying guide
Michael, Professional and passionate welder, Sheffield62 guides
Weld and welding: what’s the difference?
Welding involves uniting two or more parts into a continuous structure.
"Welding" refers to the process and "weld" to the joint produced by this process.
I've had my wrist slapped before for forgetting the distinction... A first piece of advice, start on a good footing!
What's the anatomy of a welding torch assembly?
Multi-purpose single-gas torch (also known as soldering lamp)
Autogenous or oxy-acetylene welding
- Bottled acetylene, dissolved at 17 bars, as fuel; the "warhead" (top of the bottle) colour-coded brown;
- An oxygen cylinder, pressurized to 195 bars, as an oxidizer; white warhead;
- Two separate adjustable pressure regulators;
- Two flexible hoses of different colours: blue for oxygen, red for acetylene;
- A specialized torch that ensures an appropriate mix of the two gases. Different levels of precision can be achieved with interchangeable nozzles of varying sizes.
Why oxyacetylene welding is a favourite with welders
- It's as hot as it gets, between 3100 and 3200°C - and produces three different heat zones: The tip, the pink plume (ooh pretty!) and the blue-coloured reducing zone, the crucial part of the flame for autogenous welding. I first learned that from a metalwork teacher donkey's years ago - you'll never forget once you've got the knack.
- It's easy to adjust, with a range of interchangeable nozzles provided on a star-shaped stand. These always come with the torch and are classified in terms of flow in l / min. They must always be kept clean to give a flawless flame tip: a good welder always has his welder's reamer in his pocket.
For safety reasons, a one-way valve, identical in colour to the hose in question, is placed on each hose as close as possible to the torch, to prevent the flame recoil into the gas bottles. This type of accident can result from a poorly maintained blowtorch, so take care.
How does a flame welder work?
For single gas setups, all you need to do is heat to the melting temperature of the filler metal (e.g. tin or silver solder) without forgetting to use some stripper on your components beforehand.
How are welding torches classified?
Classification of welding torches
No. 00Nozzles from 10 to 40 l/min; small welding torch.
No. 0Nozzles from 50 to 200 l/min; most commonly used type of torch.
No. 1Nozzles from 250 to 1000 l/min; high-temperature torch.
No. 2Nozzles from 1250 to 5000 l/min; heavy-duty welding torch.
First-time use of a flame welder
So, the gas cylinders are connected, the pressure regulators set at a pressure of 0.05-0.1 bar for the acetylene (C2H2) and 1-1.5 bar for the oxygen (02).
If you want to be economical, you can get a device that starts and cuts off gas flow as soon as you attach / detach your torch.
Common accidents and malfunctions
Due to the nature of the device, malfunctions are not uncommon; however, more often than not there's nothing major to worry about!
Caused by a reduction in the pressure of one of the gases or bad condition of the torch.
Clicking / snapping noise
Either the opening of the torch nozzle is blocked - in which case you should clean it with a welder's reamer - or the nozzle is becoming overheated, in which case you should cut the acetylene and leave the oxygen running to cool it down.
Visible flames inside the torch
Caused by overheating of the nozzle; turn off the gas supply and restart.
This is when the flame becomes black and dirty. Make sure your gas flow is appropriately adjusted.
Tips for choosing...
Learn more about welding equipment...
To find out more about welding equipment, follow our editors' advice and check out their other guides:
Michael, Professional and passionate welder, Sheffield 62 guides écrits
I was trained as a pipe worker and welder and worked in the industry for 15 years, going all over the UK for large-scale projects. When I decided it was time to stay closer to home - to have time for my own DIY - I took over a local metal shop and eventually went on to become head of a professional engineering firm.
I'm retired now, but I haven't stopped working with my hands. I recently built my own metalwork studio at home - a lifelong dream! I use my welding skills to make sculptures and bespoke furniture. With my studio, I managed to find a piece of paradise where I can let my imagination run wild.
I also love going around to local auctions and boot sales. I always find some interesting old object or tools that I can add to my collection or transform into works of art.
Now that I have the time, I've turned my hand to decorating, painting on canvas and gardening. I'm always developing new technologies and tools to bring my ideas to life. And I'm always happy to give others advice on how they can make their dreams a reality, too!