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Gas Nozzle Pressures

Friday, 11th December 2020
Graham (Tech Advisor)
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The correct Gas Pressures are important. Incorrect pressure can increase the risk of Flashback and make Flame Adjustment difficult.

The following Guides should help you

Lightweight & Heavy Duty Swagged Oxy/Acet Gas Welding Nozzles

Lightweight include DH type Oxy Acetylene Nozzles (not pictured)

Heavy Duty includes type 3, 4 & 5 Torches

Nozzle Size – Gas Nozzle Pressures

  • No1 – Metal Thickness = 1.0mm – Oxy/Acet Pressures = 0.15bar each
  • No3 – Metal Thickness = 2.0mm – Oxy/Acet Pressures = 0.15bar each
  • No5 – Metal Thickness = 2.5mm – Oxy/Acet Pressures = 0.15bar each
  • No7 – Metal Thickness = 3.2mm – Oxy/Acet Pressures = 0.15bar each
  • No10 – Metal Thickness = 4.0mm – Oxy/Acet Pressures = 0.20bar each
  • No13 – Metal Thickness = 5.0mm – Oxy/Acet Pressures = 0.30bar each
  • No18 – Metal Thickness = 6.5mm – Oxy/Acet Pressures = 0.40bar each

Multi-Jet Oxy Propane/Propylene Nozzles

Nozzle Size – Gas Nozzle Pressures

  • No1 – Metal Thickness = 1.0mm – Oxy/Prop Pressures = 0.20bar each
  • No3 – Metal Thickness = 2.0mm – Oxy/Prop Pressures = 0.20bar each
  • No5 – Metal Thickness = 3.0mm – Oxy/Prop Pressures = 0.25bar each
  • No7 – Metal Thickness = 4.0mm – Oxy/Prop Pressures = 0.25bar each

AHT Heating Nozzles

Nozzle Size – Gas Nozzle Pressures

  • AHT25 Oxy/Fuel Pressures = 0.30bar each
  • AHT50 Oxy/Fuel Pressures = 0.40bar each
  • AHT100 Oxy/Fuel Pressures = 0.70bar each

Oxy/Propane Super Heating Nozzles

Nozzle Size – Gas Nozzle Pressures

  • 1H Oxy Pressure = 0.7-2.0bar + Propane Pressure = 0.15-0.5bar
  • 2H Oxy Pressure = 0.7-2.0bar + Propane Pressure = 0.15-0.5bar
  • 3H Oxy Pressure = 1.8-5.0bar + Propane Pressure = 0.3-1.1bar
  • 4H Oxy Pressure = 1.8-5.0bar + Propane Pressure = 0.30-1.1bar

Oxy/Acetylene (ANM) Cutting Nozzles

Nozzle Size – Gas Nozzle Pressures

  • 1/32″ Cuts 3-6mm Steel – Pressures = Oxy 1.5bar / Acet 0.15bar
  • 3/64″ Cuts 5-12mm Steel – Pressures = Oxy 2.0bar / Acet 0.15bar
  • 1/16″ Cuts 10-75mm Steel – Pressures = Oxy 2.5-3.5bar / Acet 0.20bar
  • 5/64″ Cuts 70-100mm Steel – Pressures = Oxy 3.0bar / Acet 0.30bar
  • 3/32″ Cuts 90-150mm Steel – Pressures = Oxy 3.0bar / Acet 0.30bar
  • 1/8″ Cuts 150-300mm Steel – Pressures = Oxy 4.5bar / Acet 0.35bar

Oxy/Propane (PNM) Cutting Nozzles

Nozzle Size – Gas Nozzle Pressures

  • 1/32″ Cuts 3-6mm Steel – Pressures = Oxy 1.5bar / Prop 0.15bar
  • 3/64″ Cuts 5-12mm Steel – Pressures = Oxy 2.5bar / Prop 0.15bar
  • 1/16″ Cuts 10-75mm Steel – Pressures = Oxy 3.0-3.5bar / Prop 0.20-0.35bar
  • 5/64″ Cuts 70-100mm Steel – Pressures = Oxy 3.5bar / Prop 0.4bar
  • 3/32″ Cuts 90-150mm Steel – Pressures = Oxy 4.0bar / Prop 0.4bar
  • 1/8″ Cuts 150-300mm Steel – Pressures = Oxy 5.5bar / Prop 0.6bar

I hope you found this blog article about Gas Pressures useful.

Please let me know what you thought 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.

Cheers

Graham

The Welders Warehouse

12 comments

  1. Stephen Whymant says:

    Many thanks Graham. It sounds as if I will need two torches. The propane regulator I have been sold is a bog standard caravan type one. Is this suitable or do I need a regulator with gauges so that I can alter the pressure to suit the tip in use? Yours, Steve.

    1. Graham says:

      I wouldn’t use a Regulator designed for Caravan use!
      Pressure adjustment and at least a Delivery Pressure Gauge are pretty fundamental, have a look at our Propane Regulator. For safety, you should also use a Flash Arrestor!
      If you need any more detailed advice, give me a call, the numbers on our website.
      Hope I’ve helped, Graham

  2. Stephen Whymant says:

    Hi. I’ve been sold AFN nozzles for cutting with propane. Is that correct? I can’t get them to light. I can’t find information on the propane pressure for these nozzles. I purchased a light duty cutting attachment but can’t stop flame leakage around the nozzle holding nut. I’m new to gas cutting and primarily want to do some brazing as well. Thanks, Steve.

    1. Graham says:

      Hi Stephen
      You can get away with using an AFN Cutting Nozzle with Oxy/Propane, but it’s not ideal. There is not a readily available Nozzle on the market for Lightweight Torches I’m afraid, so you will either need to do the best you can, or buy a Heavy Duty Torch and Cutting Attachment that ARE designed for Oxy/Propane.
      The flame leakage around the Head Nut sound like a poor sealing surface on either the Nozzle or the Cutting Attachment. Contact your supplier for advice on this and pressures.
      Hope that helps (at least a bit!)
      Cheers Graham

  3. Robin Wills says:

    Hi Graham
    Im just changing to Oxy-Propylene. Can I use my BOC saffire torch and existing nozzles for brazing and bronze welding? If so do I use a different pressure?

    1. Graham says:

      Hi Robin
      Short answer is Yes you can, slightly longer answer is Acetylene Nozzles are not very good with Propylene!
      We offer a Propane Neck and Propane Nozzles that would fit your Saffire Torch. You would need to check if your Saffire is a Lightweight, or Type 3. If it’s type 3 you will also need the Neck Adaptor. If your not sure, give me a call.
      IMPORTANT, make sure you change your Regulator and Hose to a Propane type, DO NOT use Acetylene equipment with Propylene!!! If your Flash Arrestor is labelled “Acetylene” you will need to change that as well, if it’s labelled “Fuel” it will be OK.
      If you haven’t already read it, you might find my blog article Can I Use Propane or Propylene Instead of Acetylene useful
      Hope that helps
      Cheers Graham

  4. Brian says:

    Thank you for your reply. Very clear and exactly the information I requested. It’s so important to handle this equipment safely and to be sure of the correct procedures. The additional link to the setting up a gas kit was spot on. Once again many thanks.

    1. Graham says:

      Thanks Brian, glad to be of help, Graham

  5. brian says:

    Having not used oxy/propane before (only oxy/acetylene) can you explain the lighting up and setting the flame procedure please. I have just purchased your GK25 Torch and Reg set along with GHD08 Super Heater and want to get this right (I understand it may be different to Oxy/Acetylene)

    1. Graham says:

      Hi Brian
      Lighting and shutting down procedure is the same as for Oxygen + Acetylene.
      Light the Propane first (ensure there is no visible gap between the end of the Nozzle and the Flame or the flame will blow out when you turn on the Oxygen).
      Slowly turn on the Oxygen until you get the desired flame.

      You may notice that the central “Cone Flame(s)” is longer than with Acetylene, this is quite normal and is because Propane is slower burning than Acetylene.

      I’ve written a blog article on setting up a Gas Kit that includes lighting etc (it does cover Propane as well).

      If you need any further help, please call (numbers are on our main website).
      Hope I’ve helped
      Kind Regards
      Graham

  6. Peter Barnsby says:

    Hi what pressure would you recommend for the oxy3000 kit to weld lead, the same as above ? Thanks

    1. Graham says:

      Hi Peter
      Thanks for the question. Outlet Pressure for both Oxygen and Fuel gas should be no higher than 0.25bar.
      Cheers
      Graham

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