Plasma gouging consumables remove metal from the surface of a workpiece instead of cutting through it; these answers help you choose, fit and look after them.
What torch angle and height should I use when plasma gouging?
Hold the torch tilted back against the direction of travel at the angle and working height your torch manual gives. A shallower angle makes the jet skate along the surface for a wider, shallower groove, while a steeper angle drives it in for a deeper, narrower one. Treat any figure you read as a starting point, as the best settings depend on the system, the current and the job.
Do not hold the torch too close to the work, because molten metal then builds up on the nozzle, and if it is held too far away the arc loses penetration. Check your torch maker's manual for the consumables and current you are using, and practise on scrap first.
What controls the size and shape of a plasma gouge?
Several settings work together. Raising the current makes the gouge wider and deeper, and lowering it makes it narrower and shallower. Moving faster gives a narrower, shallower groove, and moving slower gives a wider, deeper one, according to plasma maker guidance.
Torch angle and height matter too: a more upright torch cuts narrower and deeper, while a longer arc stretch gives a wider, shallower groove with a smoother bottom. Always keep at least a small gap between the torch tip and the molten metal, which protects the torch and helps the parts last. The force of the arc depends on the current and the plasma gas flow rate, so keep gas settings as your manual specifies. Change one setting at a time.
Why do the small O-rings on the torch matter, and how should I look after them?
O-rings seal the gas paths in the torch head and around the consumables. Plasma maker manuals say to examine them whenever you change consumables and to replace any that are damaged. A worn or missing seal can leak gas and lead to poor arc starting or poor cut quality.
Where a seal looks dry, makers say to apply only a thin film of the silicone lubricant they specify, so that it looks shiny. Too much lubricant can prevent gas flow, so wipe off any excess with a clean, lint-free cloth, and keep lubricant off electrical contacts. Use only the lubricant your manual names, follow its instructions on which parts to lubricate, and replace seals with ones that match your torch type.
Does the quality of the compressed air affect gouging consumables?
Yes. Plasma maker guidance says moisture, oil and other contamination in the air supply can significantly reduce consumable life and cut quality, and can even harm the torch. Poor gas quality also reduces cutting and gouging performance.
Use a clean, dry supply. Built-in filters remove some moisture and dirt, but where air passes through long lines, tools that add oil, or humid conditions, makers recommend extra filtration close to the machine. Check the filter element and bowl regularly and replace the element as your manual says. Keep the pressure within the range in your manual. If consumable life suddenly drops, check the air supply first.
Is it safe to change consumables with the machine switched on?
No. Switching off at the machine alone may not remove the shock hazard if it is still connected to the supply. Plasma makers say the power supply contains dangerous voltages and that electric power should be disconnected before maintenance, with any line disconnect kept off until the work is finished.
Isolate the supply, then let the torch cool, as parts stay hot after gouging and can cause burns. Where the machine has a torch lock or disable switch, use it as an extra step, but do not rely on it or on any interlock instead of isolating the supply. Refit parts in the right order and tighten them as the manual describes, and follow the maker's instructions for your torch.
How are gouging consumables different from cutting consumables?
Gouging consumables are a separate family from cutting ones. Plasma makers publish distinct gouging parts, and the tip shape and shield are designed to remove metal from the surface rather than cut through it.
Gouging parts also come in different styles. Some are aimed at controlled, shallow removal and light washing, some at heavy removal and deep profiles, and some at very small removals at low current. Gouging shields are intended to protect the tip from molten metal, so use the tip and shield combination your torch manual lists. Check your manual for the parts your torch is designed for, and keep gouging and cutting parts clearly separated.