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Model O Torch

Thursday, 19th March 2020
Graham (Tech Advisor)
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Model O – a little bit of History

We’ve been selling the original Model O Torch for some Years now.  It’s always been a popular torch, especially among Roofers, who use it for Lead Welding and LOVE the feel of the torch and the precise flame adjustment that can be achieved.

Now, after over 30 Years of the above model O, we’ve updated the design to incorporate some tweaks that customers have expressed a desire for.

Model O – the Next Generation

The first thing to say is we haven’t changed very much!  After all, if a Torch is as popular as the Model O it would be stupid to re-invent the proverbial wheel 🙂

So what have we changed?

We’ve now made the Oxygen Inlet from a single forged piece of Brass, rather than two pieces brazed together.  This increases the strength and durability of the whole Torch, plus improves Oxygen Gas Flow.

We’ve tweaked the geometry of the valves to provide even better and more precise flame adjustment.

We’ve increased the angle of the Neck Bend as LOADS of customers, old and new, told us the angle on the old torch wasn’t tight enough.

Model O Nozzles

The original Model ‘O’ Nozzles are designed for Oxy/Acetylene or Oxy/Hydrogen.

Model O Nozzle (Oxy/Acet)
Model ‘O’ Nozzle for Oxy/Acetylene

These original Model O Nozzles are VERY small.  They’re numbered 1-5 with 5 being the biggest.  Having said “Biggest” it’s worth noting that the number 5 is only slightly bigger than a conventional torch No1.  So the term “Biggest” is somewhat subjective!

The most popular Oxy/Acetylene Nozzle is the No3, which Roofers use for Code 4 Lead Welding.  Although all the nozzles sizes  are popular.

No1 nozzle produces such a tiny flame I’m pretty sure you could weld a KitKat wrapper with it 🙂

Oxy Propane/Propylene Nozzles

Launched in 2020, our Pro-Jet dedicated Oxy/Propane or Propylene Nozzles.

These feature a small ring of tiny nozzles, surrounding a central main flame.  The purpose of this design is to allow the greater volume of fuel gas that’s necessary for liquefied gases, to flow and burn efficiently.

Model O Oxy Propane or Propylene Nozzle
Pro-Jet Model O Nozzle

Pro-Jet Nozzles are available in numbers 1, 2 & 3.  (3 being the biggest).

Customer feedback has been excellent, with Roofers telling us the No1 nozzle is ideal for Code 4 Lead.

Using the standard Oxy/Acetylene Nozzles for Oxy Propane or Propylene is ok, but the torch is difficult to light and the flame blows out REALLY easily.  This is because Propane and Propylene are liquifed gases that burn a lot slower than Acetylene.

Pro-Jet Nozzles overcome these problems and are much easier to light, especially in windy conditions!

Using the Model O

The single biggest problem that customers report with using their Model O Lead Welding Torch is difficulties with flame adjustment.  This usually means the flame blows out too easily when lighting, or the flame pattern changing on its own.

In 95% of cases, this is caused by too much gas pressure being set on the Regulator.  When customers report problems and we ask what pressure they have set, we invariably get figures around 1.0 to 1.5 bar.  The correct pressure is between 0.15 and 0.2 bar!!!!  This is barely off the Zero Pin of a Regulator!

Gas Regulator Selection

The problem of setting too higher Gas Pressure derives from one of two things

The operator thinks that 1.0 – 1.5 bar is the correct pressure IT IS NOT!

The operator has a 0-10bar Oxygen Regulator.  Trying to set a STABLE pressure of between 0.15 and 0.2bar on a Regulator with up to 10bar of pressure is virtually impossible!!!

Here at The Welders Warehouse, we offer a 0-4bar Oxygen Regulator for lower pressure applications, which is actually MOST applications!  A 0-4bar Oxygen Regulator is far better for setting and maintaining the stable low pressure needed for using a Model O Lead Welding Torch.  A 0-4bar Oxygen Regulator is suitable for most Welding and Light Cutting Torches.  A higher output Oxygen Regulator would only be necessary for Cutting Nozzles above 5/64″.

Lighting a Model ‘O’ Torch

There is no real difference between lighting  Model ‘O’ Torch to lighting any other kind of Oxy Acetylene Torch.  It’s just more important to make sure the gas pressure on the Regulators is set correctly and only turning the Torch Valves by very small amounts at a time.  The key thing to remember is that with such small nozzles, small changes can make a big difference, so changes have to be made gradually.


The Model O Torch is still the first choice for Lead Welders and the new Torch fine tunes all the things Lead Welders loved about the original.  As long as the Oxy Acetylene Kit is set up correctly, the new Model O will provide Years of trouble free Lead Welding.

To visit our Model O page, where you will find prices and can order, Click Here.

I hope you found this blog article useful, if things work out well for you, please feel free to post some pictures of your achievements on our Facebook Page

Please let me know what you thought of this article by leaving a comment.  Don’t worry, your email address won’t be added to a database or shared and you won’t receive any unsolicited email.



The Welders Warehouse

14 responses to “Model O Torch”

  1. Jeff Terrell says:

    Hello Graham,
    Thanks for your prompt reply. I bought a general purpose triangular shaving hook (Toolstation, 58907, £2.92) to clean up the joints and the welding sticks before starting to weld and all my problems disappeared. Many thanks for your help.

  2. Jeff Terrell says:

    Hello Graham,
    Last week, I bought a lead welding kit from you. It’s a very nice tool, but I haven’t found it that easy to produce a professional finish. In spite of cleaning the joints thoroughly with wire wool, I can’t get the solder to flow properly and I’ve therefore resorted to using flux. What do you use to clean the joints? Also, do you make your own welding rods from spare lead? I’m using a roll of lead which is probably used more for soldering than welding. Thanks. Jeff.

    • Graham says:

      Hi Jeff
      Good to hear you’re pleased with the quality of your kit.
      Most pro Lead welders scrape the edge of the lead with a scraper tool to expose clean, bright lead. Essentially, you need to remove the dull grey oxide layer. Wire wool should also work, as long as you end up with clean bright material.
      Most pro lead welders will cut a thin strip off the lead they need to weld, to use as a filler wire. This guarantees the lead is exactly the same as the material to be welded, it’s also cheaper than buying cut lengths for filler wire.
      As long as both the lead to be welded and the filler rod are clean and bright (Oxide layer removed), you should not need flux.
      After that it’s down to technique!
      The Lead Sheet Training Academy in Kent offer some very good courses and also have some YouTube videos that might be worth you watching (search “Lead Sheet Training Academy” for within YouTube).
      Other Lead Welding course providers are also available, including some local Colleges.
      Hope I’ve helped.
      Kind Regards

  3. John says:

    How do you set an oxy propylene set up but using the same oxy/ acetalyne setup

    • Graham says:

      Hi again John
      You must not use Acetylene kit with Propane or Propylene!!!
      Propane & Propylene will corrode the inside of Acetylene Hose and internal parts of Acetylene Regulators and Flash Arrestors. You must use a Propane Regulator, Propane or “Fuel” Flash Arrestor and Propane Hose.
      Sorry that it’s probably not what you want to hear! but you need to stay safe, so I hope it helps.
      Cheers Graham

  4. John says:

    Can an oxyturbo kit be converted to take a model o torch or the lead master torch

    • Graham says:

      Hi John
      Thanks for the question.
      YES, you can.
      You will need to cut the Oxy/Turbo Torch off and fit a Gas Hose Nut and Tail set to the Hoses. You will need a “5mm RIGHT Hand ¼” Thread” for the Oxygen and “5mm LEFT Hand ¼” Thread” for the Fuel Gas.
      Either the Model ‘O’ or LeadMaster will then fit onto those fittings.
      You can find the fittings via the following Link and using the “Options” Drop Down Menu.
      Gas Hose Nut & Tail Set
      Hope I’ve Helped
      Cheers Graham

  5. John Hall says:

    Hi, is it possible to use the model 0 with propane instead of acetylene?
    Cheers John

    • Graham says:

      Hi John
      Thanks for the question. Yes, it is possible to use the Model O with Oxygen + Propane. You can use the standard Nozzles, but will need a bigger one than with Oxy/Acetylene. Oxy/Propane with a No4 or 5 Nozzle will work fine. Oxy/Propane is a bit harder to light and will be more prone to blowing out, this is because Propane is a much slower burning gas than Acetylene. But other than that, all will be OK.
      Hope I’ve helped
      Cheers Graham

  6. nicolas castro says:

    hi graham
    what is acetylene pressure for model 0 torch

    • Graham says:

      Hi Nicolas
      Thanks for the question.
      Both Acetylene and Oxygen should be around 0.15bar (2.2psi), depending on Nozzle Size. You should certainly not exceed 0.25bar (3.7psi) for any nozzle as too much pressure will make the Torch valves VERY finiky to adjust.
      Our Next Generation Model ‘O’ Torch has the pressure for each Nozzle on the box.
      Hope I’ve helped.

  7. Richard Fenwick says:

    Very useful and informative. Please could you do an article for beginners like me trying to use and oxy/propane torch but without a lot of success particularly with regard to nozzle sizes, lighting and adjusting to the correct flame type. Many thanks.

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