Welcome to John Duff Limited!

We are a multifaceted custom metal fabricating company located in Petrolia, Ontario. We have been in the steel fabricating industry for almost 50 years, allowing us to offer our customers a wealth of knowledge and experience.  The work we create is both unique and long lasting and we are capable of producing one-offs, or  production runs.

Visit our gallery of photos to view some of the interesting projects we have worked on in the past. We service a number of industries, including the industrial, manufacturing, agricultural, commercial and construction industries.

It is our pleasure to partner with our customers, to help them materialize their vision, and to ensure that each project is completed with the highest quality of workmanship.  Our fabricators take great pride in their skills and the results show in their work!


  • Shearing & Forming
  • Rolling
  • Punching
  • Specializing in Stainless and Aluminum Welding
  • Platforms
  • Stairs & Railings
  • Stair Pans
  • Pipe Clamps made to order
  • Cones
  • Truck Boxes
  • CNC Plasma Cutting
  • Miscellaneous Metals
  • Ductwork
  • Dust Collectors & Plenums
  • Cyclones
  • Hoppers
  • Electrical Boxes
  • Water Treatment and Sewage Plant Fabrications
  • Header Boxes
  • Tank Repairs
  • Fire Truck Modifications
  • Ornamental Work


  • Canadian Welding Bureau certified to CSA W47.1/W59
  • Canadian Welding Bureau registered to CSA W47.2 Aluminum