Can plasma cutters cut aluminum?
Yes. Plasma cuts anything that conducts electricity, aluminum included. The useful question is what the edge comes out like, and what you have to do to it next.
The short answer
Yes. Plasma cutting works on any electrically conductive metal, and aluminum is one — an ordinary air plasma cutter will cut it today with the air and consumables it already has. The trade is edge quality: Hypertherm states that with an air plasma system the cut surface on aluminum "will tend to be rough and require some rework if aesthetics are important", and that "the cut surface can oxidize leaving you with porous welds". For cutting parts out, air is fine. For parts you will weld or leave on show, plan to clean the edge back first.
Why plasma does not care what the metal is
Plasma cutting works by blowing an ionized gas jet through an electrical arc that runs from the torch electrode to the workpiece. The arc melts the metal and the gas jet blows the molten metal out of the kerf.
The only property the process requires is electrical conductivity, because the workpiece has to be part of the circuit. Aluminum is an excellent conductor, so it cuts. So does stainless, copper and brass.
This is the real difference between plasma and an oxy-fuel torch. Oxy-fuel works by oxidizing iron, which means it works on mild steel and genuinely does not work on aluminum or stainless at all. Plasma against oxy-acetylene works through that properly.
What the aluminum cut edge actually looks like
Expect three differences from the same machine cutting mild steel.
More dross on the underside. Aluminum stays molten over a wider temperature band than steel and is less willing to be blown clear, so more of it re-solidifies on the bottom edge. It knocks off, but it is there.
A rougher face. Hypertherm's own guidance on air plasma is that the surface finish tends to be rough and needs rework where appearance matters.
An oxidized skin. Hypertherm notes that air plasma produces some nitriding and oxidation of the cut surface, and that this can cause porosity in subsequent welds. On aluminum, which already forms a tenacious oxide in open air, this is the consequential one.
If you are going to weld the cut edge, clean it first
An air-plasma cut edge on aluminum carries oxide and nitride that will produce porosity in a TIG or MIG weld. Take the edge back to bright metal with a dedicated stainless wire brush or a flap disc kept only for aluminum — a brush that has been used on steel transfers iron into the joint and causes exactly the contamination you were trying to remove.
The gases that improve it, and whether you have them
Industrial plasma systems can run gases other than air, and the improvement on aluminum is real. Hypertherm's published gas selection guidance for aluminum is:
| Aluminum thickness | Plasma gas | Shield / secondary gas | Notes |
|---|---|---|---|
| Under 5 mm (about 3/16 in) | Nitrogen | Nitrogen | Cleaner edge than air |
| Over 6 mm (about 1/4 in) | Nitrogen | Water | Only on systems with water shield capability |
| Over 12 mm (about 1/2 in) | H-35 or H-2 hydrogen mixture | Nitrogen | Best edge quality on thick plate |
| Under 1/2 in, multi-gas system | Nitrogen | Air, CO2, or water | Hypertherm's general gas selection guide |
| Over 1/2 in, multi-gas system | Argon-hydrogen | Nitrogen | Rated excellent on thick plate |
| Any thickness, air plasma system | Air | Air | Works; rougher and oxidized edge |
The honest consequence for a home shop: none of this is available to you. Every machine on this site is an air plasma system, and Hypertherm is explicit that on a Powermax you use air as both plasma and shield gas. Switching gases is a property of multi-gas industrial equipment, not an upgrade you buy for a handheld cutter.
Hypertherm also warns against running air as the plasma gas on a multi-gas system set up for aluminum, which produces "a rough and heavily oxidized black surface along with heavy dross". That is a configuration problem rather than something a handheld machine can do.
Never cut aluminum under water with an H-35 or H-2 mixture
Hypertherm states this directly, and the reason is hydrogen accumulation and explosion risk. Underwater cutting is industrial-table territory and is not something a home shop does, but the warning is absolute enough to carry here.
How much aluminum your machine will actually cut
Every published cut-thickness figure you will see is a mild-steel figure. Aluminum conducts heat away from the kerf far faster than steel, which spreads the heat-affected zone and reduces the thickness a given amperage will cut cleanly.
So treat a machine's mild-steel rating as a ceiling you will not reach on aluminum rather than a figure that transfers. A machine publishing a 5/8-inch clean cut in steel is not a 5/8-inch aluminum machine, and the only honest way to find your real number is a test cut on the stock you actually have.
The cut thickness chart sets out what clean cut, recommended cut and severance cut each mean, which is the distinction that matters most when you are judging whether a machine covers your work.
Air quality matters more on aluminum than on steel
Moisture in the air supply is the single most common cause of a poor plasma cut, and aluminum shows it first.
Water in the plasma stream destabilizes the arc, throws the cut off square, accelerates consumable wear and leaves a visibly ragged edge. A compressor with a tank full of condensate and no water separator will do all of that, and the symptom looks exactly like a machine that is underpowered.
A water separator and a desiccant filter in the line are not accessories for aluminum work, they are part of the machine. Whether plasma cutters need gas covers what the air supply actually has to be, and plasma cutter air requirements covers CFM and PSI sizing.
Fume: aluminum is not steel
Cutting aluminum produces a fine metal-oxide fume, and on anodized or painted stock you are also burning the coating. Plasma cutting generates substantially more airborne particulate than welding does, because the process is designed to blow molten metal out of the kerf.
Cut outdoors or with real extraction, and wear a half-mask respirator rated for metal fume under the helmet. Respirators and fume safety sets out what that means in practice. Shade 8 is the minimum lens shade for plasma arc cutting under 300 amps, which covers all home work — the shade chart has the table.
What we would buy
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1. Cuts aluminum with no compressor at all
Lincoln Electric Tomahawk 30 AIR
Internal compressor matched to the torch, 5/16 in recommended on steel, 230 V only.
Lincoln publishes 15 to 30 amps, an internal air compressor that needs no external air supply or filter, an external air connection as standard, a 230-volt single-phase input, a recommended cut of 5/16 inch mild steel at 22 inches per minute, a 3/8 inch maximum at 14 ipm, a 1/2 inch severance cut at 5 ipm, and 40 pounds.
The internal compressor is more relevant to aluminum than it first appears. Moisture in the air supply is what produces a ragged, dross-heavy edge, and aluminum is the material least forgiving of it. A matched internal supply with its moisture handling built in removes the most common cause of a poor aluminum cut.
Derate the published thickness figures for aluminum. They are mild-steel ratings, and aluminum conducts heat away from the kerf far faster.
What works
- The compressor is inside the machine, so the hidden second purchase that sinks most first plasma buys does not exist
- It takes external air as standard as well, so a shop compressor can carry the long cuts the internal pump has to pause for
- 25 A at a 100% duty cycle is a genuinely continuous rating rather than a figure you have to work around
- Lincoln publishes three years on the machine and a dealer network behind a tool that eats consumables
What does not
- 230 V single phase only. There is no 120 V option, so a garage without a 240 V circuit cannot run it at all
- 40 lb, which is portable for a machine carrying its own compressor but not the under-30-lb class
- Costs multiples of a budget 50 A machine while cutting thinner material
- Buy on the 5/16 in recommended figure: 1/2 in is a severance limit at 5 ipm, not a working thickness
2. Most aluminum capacity per dollar
Lotos LTP5505D
Pilot arc and a 5/8 in clean cut on 240 V, if you already own a real compressor.
Lotos publishes 20 to 55 amps on 220/240 volts and 20 to 35 amps on 110/120 volts, a 5/8 inch clean cut at 220 volts, a 3/4 inch severance cut, a non-touch pilot arc, and a built-in pressure regulator with an external compressor required.
The pilot arc is the feature that matters on aluminum. Aluminum carries an oxide layer that forms the moment the metal meets air, and a touch-start machine has to break through it to establish an arc. A non-contact pilot arc simply starts.
The honest condition attached to this machine is air. It needs a real compressor delivering clean dry air; a pancake compressor will starve it, and starved air ruins both the cut and the consumables. Plasma cutter air requirements covers the sizing.
What works
- Pilot arc means it will start on painted, rusty or galvanized material where a touch-start machine stalls
- 5/8 in clean cut on 240 V is more capacity than most home shops will ever use
- Publishes a complete specification on BOTH supplies — output, clean cut, severance and duty cycle — which most dual-voltage machines do not
What does not
- You must supply clean dry air. A small pancake compressor will not keep up, and wet air destroys consumables fast
- On a 110 V outlet the top end falls from 55 A to 35 A and the clean cut from 5/8 in to 3/8 in
- The output floor is 20 A rather than the 10 A some competing machines publish, so it throttles down less far for thin sheet
- Consumable life is noticeably shorter than Hypertherm's, and the running cost shows it
3. For thicker aluminum plate
PrimeWeld CUT60
60 A with pilot-arc start, for plate where a 50 A machine is working at its limit.
PrimeWeld publishes 60 amps, a non-touch pilot arc, and an external compressor requirement, on 220 volts only.
Because aluminum draws heat out of the cut zone so quickly, the useful thickness on aluminum is meaningfully below a machine's mild-steel rating. The practical consequence is that aluminum is the material where buying amperage headroom actually pays — a 60-amp machine on half-inch aluminum is working comfortably where a 50-amp machine is at its limit.
Air demand at 60 amps is beyond what a small compressor can sustain. Budget the compressor as part of the purchase, not after it.
What works
- 60 A gives real headroom on 1/2 in plate instead of treating it as a severance cut
- Pilot-arc start and a well-regarded torch for the price
What does not
- Air demand at 60 A is beyond what a small compressor can sustain — budget for the compressor as part of the purchase
- Dual voltage, but on 120 V PrimeWeld publishes only 20–30 A — half the machine. The 60 A you are paying for needs a 240 V circuit
Who this is wrong for: A shop with a small compressor or no 220 V circuit. At 60 A the air supply is the real purchase, and the machine is 220 V only.
Questions people actually ask
Can a plasma cutter cut aluminum?
Yes. Plasma cutting works on any electrically conductive metal, and a standard air plasma machine will cut aluminum with the air and consumables it already has.
The cut edge is rougher than the same machine's edge on mild steel, with more dross underneath and an oxidized surface, so plan on cleaning it up if appearance matters or if you intend to weld it.
What gas is best for plasma cutting aluminum?
On a multi-gas system, Hypertherm recommends nitrogen plasma with a nitrogen shield under about 5 mm, nitrogen with a water shield over 6 mm, and an H-35 or H-2 hydrogen mixture with a nitrogen shield over 12 mm.
On a handheld air plasma machine — which is what every home shop has — you use air for both plasma and shield. Switching gases is a property of industrial multi-gas equipment, not an upgrade for a handheld cutter.
Why is my plasma-cut aluminum edge rough?
Three usual causes. Air plasma inherently leaves a rougher surface on aluminum than on steel. Moisture in the air supply destabilizes the arc and leaves a ragged edge, which is the most common fixable cause. And aluminum draws heat away from the kerf faster than steel, so a machine near its thickness limit struggles sooner.
Fit a water separator and a desiccant filter first; that resolves most of it.
Can you weld a plasma-cut aluminum edge?
Not without cleaning it. Hypertherm notes that air plasma produces nitriding and oxidation of the cut surface, which causes porosity in welds.
Take the edge back to bright metal with a flap disc or a stainless wire brush kept exclusively for aluminum — a brush previously used on steel transfers iron into the joint.
How thick an aluminum plate can a home plasma cutter handle?
Less than its published rating, because every published cut-thickness figure is a mild-steel figure and aluminum conducts heat away from the kerf far faster.
Treat the steel rating as a ceiling you will not reach, and establish your real number with a test cut on the stock you actually have.
Sources
- Hypertherm — Plasma cutting aluminum: what you need to know
- Hypertherm — Gas selection guide for plasma cutting aluminum, stainless steel and mild steel
- Lincoln Electric — Tomahawk 30 AIR (K5457-1) published specifications: 15–30 A, internal air compressor with an external air connection standard, 230 V 1-phase input, 5/16 in recommended cut at 22 ipm, 40 lb
- OSHA — Arc welding and cutting standard (29 CFR 1910.254), protective shade numbers
Read next
- Do plasma cutters need gas?
Every plasma cutter needs a gas — but for home machines that gas is shop air, not a bottle.
- Plasma cutter cut thickness chart
Recommended versus severance capacity by amperage, and what you lose on a 110V outlet.
- Plasma cutter air requirements
How to read CFM and PSI, why tank size is not the answer, and what a compressor must sustain.
- The best plasma cutters for home use
Home-shop machines, why the compressor is the real purchase, and how to read cut-capacity numbers.
- Plasma cutter vs oxy-acetylene torch
Where each process wins on thickness, cost and material — and the two metals oxy-fuel cannot cut.
- Level 4 · Plasma: cutting as accurately as you weld
The only rung on this ladder that is about shaping metal rather than joining it — and the one where the machine is the smaller half of the purchase.
Back to Level 4 · Plasma, or start over at Find Your Level.
Ryder M.
Ryder M. is the hands-on owner behind Magoo Media Group. He writes Arc & Bead's buying guides and picks every machine on the site. What every recommendation is based on — and what it is not based on — is set out on How We Pick.