Disclosure: This post contains affiliate links and I will be compensated if you make a purchase after clicking through my links. Learn More
Can a plasma cutter cut aluminum? Yes, and Hypertherm states plainly that a plasma cutter will cut aluminum, from thin sheet to thick plate.
Plasma cuts electrically conductive metal, and aluminum conducts electricity very well. The catch is edge quality: shop air leaves a rougher, oxidized edge, and nitrogen gives a cleaner one.
The biggest hazard with aluminum shows up on water tables, where trapped hydrogen can build up and explode. A few simple rules keep that risk off your bench.
Can a Plasma Cutter Cut Aluminum? The Short Answer
Yes. An air plasma cutter that cuts mild steel will also cut aluminum, and Hypertherm says air on its Powermax systems gives good cut quality on aluminum. Set amperage and speed from the aluminum cut chart in your owner’s manual.
Why Plasma Works on Aluminum
A plasma cutter pushes an electric arc through a narrow nozzle with compressed gas. The arc melts the metal and the gas stream blows it out of the kerf.
The arc needs an electrically conductive workpiece, so aluminum, stainless steel and mild steel all cut. Hypertherm points out that aluminum’s reflective, soft and heat-conductive nature makes fiber and CO2 lasers challenging and expensive on it. Plasma has no reflection problem, which is one reason shops pick it for aluminum plate.
Best Gas for Plasma Cutting Aluminum
For most handheld cutters the choice is short. Hypertherm’s Powermax FAQ says your two options are compressed air or nitrogen. Powermax torches are gas-cooled, so other gases can be dangerous in them.
| Gas | Result on Aluminum (Hypertherm) | Best For |
|---|---|---|
| Clean, dry shop air | Good cut quality and speed, rough and oxidized edge | Lowest cost, air-only cutters |
| Nitrogen (air, CO2 or water shield) | Excellent cut quality; water shield gives a smooth, shiny edge | Aluminum under 1/2 inch on multi-gas systems |
| H-35 (35% hydrogen, 65% argon) | Excellent on plate over 1/2 inch | Thick aluminum on systems built to run it |
| Oxygen | Not recommended | Mild steel |
| F5 | Not recommended for aluminum | Stainless steel |
Never put a gas in your torch that its manual doesn’t list. Hypertherm warns that a system must be equipped for safe operation with argon-hydrogen gas before you run it.
Gas Choice by Aluminum Thickness
Hypertherm’s aluminum guidance for multi-gas and mechanized systems changes with plate thickness.
| Aluminum Thickness | Suggested Setup (Hypertherm) |
|---|---|
| Under 3/16 inch (5 mm) | Nitrogen plasma, nitrogen shield |
| Over 1/4 inch (6 mm) | Nitrogen plasma, water shield |
| Over 1/2 inch (12 mm) | H-35 or H-2 plasma, nitrogen shield (works especially well over 3/4 inch, 20 mm) |
On an air-only handheld cutter, clean, dry air is your gas at every thickness. Your machine’s rated cut capacity and its aluminum cut chart set the limit.
What Cut Quality to Expect on Aluminum
With air, expect a rougher surface and some oxidation along the edge. Hypertherm says that oxide can cause porous welds if you weld the edge without rework.
On multi-gas mechanized systems, Hypertherm doesn’t recommend air for aluminum at all. On those machines it leaves a rough, heavily oxidized black surface with heavy dross.
With nitrogen and the right settings, Hypertherm says you can get a very nice edge with little angle variation and very little dross on thick and thin aluminum.
How to Plasma Cut Aluminum: Tips for a Cleaner Edge
These 5 steps come from Hypertherm’s aluminum advice and work on most handheld air plasma cutters.
Credit: www.youtube.com
Step 1: Use the Aluminum Cut Chart
Find the aluminum chart in your owner’s manual and set amperage, speed and standoff from it. Hypertherm’s answer to a Powermax owner asking about aluminum was simply to follow those charts.
Step 2: Clean and Dry Your Air
Hypertherm’s gas guide says shop air for plasma must be cleaned and dried. Run a filter or dryer between the compressor and the cutter.
Step 3: Hold the Standoff and Skip Drag Cutting
Keep the torch at the standoff your manual lists. Hypertherm’s aluminum tips say not to drag-cut, so use a standoff guide or a steady hand.
Step 4: Cut in One Direction
Move the torch in one steady direction at the chart speed, as Hypertherm recommends. Clamp a straightedge to the plate for long cuts.
Step 5: Clean the Edge Before You Weld
Grind or file back the oxidized layer on an air-cut edge. That removes the oxide Hypertherm links to porous welds. Its gas guide adds that weld wire with deoxidizers and denitriders usually corrects the porosity.
If you plan to MIG weld aluminum parts after cutting, finish the joint area with a clean stainless steel wire brush kept only for aluminum.
Water Table Safety When Cutting Aluminum
Aluminum and water can produce hydrogen during plasma cutting. Hypertherm warns that bubbles that don’t escape can build up over days or weeks and can explode.
Hypertherm’s manual tells you not to cut aluminum underwater or with water touching the underside of the plate. Its blog adds that you should never plasma cut aluminum underwater with H-35 or H-2 gas.
Credit: www.youtube.com
- Use a water table built by a company with experience in aluminum cutting, as Hypertherm advises.
- Keep the water level low enough that it never touches the underside of aluminum plate.
- Connect the water table to an earth ground.
- Wear eye and face protection rated for plasma cutting, leather gloves and flame-resistant clothing.
- Ventilate or extract the fumes, and keep flammable material away from sparks and molten metal.
Frequently Asked Questions
What Thickness of Aluminum Can a Plasma Cutter Cut?
It depends on the machine. Each cutter lists its rated cut thickness in the manual, often for mild steel first. Check the aluminum cut chart for your model, since aluminum settings differ. Hypertherm suggests H-35 gas for mechanized cuts on aluminum over 1/2 inch.
Can You Plasma Cut Aluminum With Shop Air?
Yes. Clean, dry shop air is the most economical way to plasma cut aluminum, per Hypertherm’s gas guide, and it gives good cut quality on air-only Powermax systems. Expect a rougher, oxidized edge, so clean it before welding to avoid porosity.
Why Is My Plasma Cut on Aluminum Black and Rough?
A black, rough edge usually comes from oxidation when you cut with air. Hypertherm says air on multi-gas systems leaves a heavily oxidized black surface with heavy dross. Switch to nitrogen if your system allows it, and check speed and amperage against the cut chart.
Is Plasma Cutting Aluminum Dangerous?
It carries the usual plasma risks of shock, UV light, fumes and fire, plus one extra hazard. Aluminum over water can build up hydrogen that explodes. Never cut aluminum with water touching the underside of the plate, and use a water table built for aluminum.
Can You Use Argon to Plasma Cut Aluminum?
Not in a handheld air plasma cutter. Hypertherm says Powermax torches take only compressed air or nitrogen, and other gases are potentially dangerous because the torch is gas-cooled. Argon-hydrogen H-35 is for mechanized systems equipped to run it safely on thick aluminum.
Final Words
A plasma cutter cuts aluminum without trouble. Clean, dry air works on most handheld cutters, and nitrogen gives a cleaner, shinier edge where your system supports it.
Set up from your manual’s aluminum cut chart, clean the edge before you weld, and treat water tables with care. Keep water off the underside of aluminum plate, and never cut it underwater with hydrogen-based gases.
