You scroll Trade Me.
See a plasma cutter.
Price looks good.
Photos are average.
Description says something like: “Works mint. CUT50. Hardly used.”
You think:
“Yeah sweet, that’ll do.”
You buy it.
It turns up.
No box.
No manual.
No paperwork.
No idea what brand it really is.
Just a machine and a torch hanging off the front.
Welcome to the world of secondhand plasma cutters.
Secondhand Means Mystery
With a brand-new machine, at least you sometimes get a manual.
With Trade Me machines?
You get whatever the seller remembered to throw in the box.
Half the time the seller doesn’t even know what they’ve got.
They just know it turns on.
So if you’re trying to buy consumables based on:
● Model name
● Sticker on the case
● What the seller told you You’re guessing.
And guessing costs money.
A Quick Word on Old Industrial Machines
You’ll see some older industrial plasma cutters on Trade Me.
Big heavy units.
Often 3-phase.
Most home garages can’t even plug them in.
On top of that, those machines usually run bloody expensive torches and consumables.
Not beginner-friendly gear.
What we’re talking about here are the common Chinese-built home workshop plasma cutters that make up most Trade Me listings.
That’s where PT31 and AG60 live.
The Torch Might Not Be Original
On secondhand machines, the torch may not even be the one it left the factory with.
People swap torches.
People replace leads.
People fit whatever was cheap at the time. So even if the machine used to run PT31…
It might not anymore.
You can’t assume anything.
You must look at the torch that’s physically on the machine right now.
No Torch? Not The End of the World
Some machines turn up with no torch at all.
Annoying.
But not fatal.
In most cases, you can fit a replacement PT31 or AG60 torch and keep going.
The machine doesn’t care what brand the torch is.
It only cares about the style.
Most Trade Me Plasma Cutters Fall Into Two Torch Types
From what I see in NZ sheds, most secondhand machines fall into:
● PT31 / LG40 (scratch-start)
● AG60 (pilot-arc)
Not all.
But most.
Once you know which one you’ve got, the consumables problem disappears.
If The Tip Pushes In → PT31 / LG40
Pull the front cap off.
If the cutting tip:
● Pushes in
● Does NOT screw in And the electrode:
● Is double-ended
● Can be flipped around
You’re running a PT31 / LG40 scratch-start torch.
This is the most common torch I see on Trade Me plasma cutters.
Standard vs Extended – Easy To Stuff Up
PT31 / LG40 consumables come in:
● Standard length
● Extended length
Both fit the same torch body.
But they must match.
Standard electrode → standard tips
Extended electrode → extended tips Mix them and the cutter turns into a moody bastard.
Hard starts.
Ugly arc.
Tips dying fast.
Ask me how I know.
What “Scratch-Start” Means
Scratch-start means the torch must touch the metal to start.
Pull trigger.
Tip touches steel.
Lift slightly. Arc starts.
Simple.
Cheap.
Common.
If The Electrode Screws In → AG60
If the electrode:
● Screws into the torch
● Is NOT double-ended
And the tip:
● Also screws in
You’ve got an AG60 pilot-arc torch.
What “Pilot-Arc” Means
Pilot-arc means the torch fires a small arc inside itself first.
Then it transfers to the metal.
You don’t need to touch the steel.
Better for:
● Rust
● Paint
● Mesh
● Dirty material Different torch.
Different consumables.
AG60 parts will not fit PT31.
What Consumables Fit Once You Know Your Torch
Push-in tip + double-ended electrode → PT31 / LG40 consumables
Screw-in electrode + screw-in tip → AG60 consumables
That covers most Trade Me plasma cutters in NZ.
Quick Reality Check – Machine Struggling To Cut?
A lot of secondhand buyers think their machine is weak.
Half the time it’s setup or expectations.
I covered this properly here:
Why Is My Plasma Cutter Struggling to Cut Thick Steel?
Worth reading before writing the machine off.
The Big Takeaway
Secondhand machines are a lucky dip.
Brand doesn’t matter.
Model doesn’t matter.
What the seller said doesn’t matter.
Your torch matters.
Identify it first.
Then buy consumables.