Carbon Arc Air Cutting

[zeppelin builder]

dont forget oxy/acetylene gouging its worked for almost a century
even washing off parts can be done with a regular cutting nozzle in skilled hands

i think arc air gouging with anything less than an 8 mm carbon and big amps is a waste of time
finish should be smooth not the appearance of a rat chewing it
minimal grinding is what your aiming for

 

[Memmeddu]

dont forget oxy/acetylene gouging its worked for almost a century
even washing off parts can be done with a regular cutting nozzle in skilled hands

i think arc air gouging with anything less than an 8 mm carbon and big amps is a waste of time
finish should be smooth not the appearance of a rat chewing it
minimal grinding is what your aiming for

Would plasma gouging be an option for hobby and light duty gouging?

 

[davidjohnperry]

Would plasma gouging be an option for hobby and light duty gouging?

Plasma gouging is great butttt as far as I'm aware only hypertherm 45xp and the 3 phase models have gouge mode plus you need the tips and shroud I doubt the cheaper models would be able to do it plus gouging unless you do it for a job or have lots of welds to remove I don't see the point I do it when I need to because it's my job but doing it as a hobby is just as expensive as welding or can be gas is probably the cheapest way

 

[Munkul]

There's a cheap way to gouge on any plasma... drill a cutting nozzle out a little. It works very well I've done quite a bit of weld gouging on both my old 40 amp IFL and now my 65 amp Tecarc. The built in standoff on the drag shields can be cut back for better access.

It's not the fastest method in the world, you'd be faster with oxy propane, but you do get a lot of control with it, as the way the plasma arc curves into the steel is very predictable.

Ultimately you'll still need an angle grinder to get any meaningful work done.

 

[Pete1961]

Just as an interim Has anyone used 9'' Diamond discs aimed at metal cutting? Is there any saving over abrasive cutting discs, ie. you might get one for £20 vs a pack of 20 abrasives.

 

[davidjohnperry]

I'm confused is your aim to cut metal or gouging metal standard 9inch grinding disks will take welds out as fast as any it depends on the purpose
Gouging great for crack repairs or removing porosity in butt welds or removing welded parts with out damaging parent metals depending on skill
But if you want to cut metal any abrasive plasma band saw what ever cuts metal depending on thickness any will do as good a job

 

[Sergei Slovenija]

There's a cheap way to gouge on any plasma... drill a cutting nozzle out a little. It works very well

I want to see it

 

[Memmeddu]

I knew that reducing air pressure and using worn out nozzles on a plasma cutter would do the trick , if you have not gouging consumables

 

[davidjohnperry]

OK here is a short video of some gouging stuff

 

[davidjohnperry]

This is not the only way there are lots and lots of ways to gouge I might not be correct in some of my description but I've done quite bit of flame and rod gouging but not much air arc but enough to understand how its done properly

 

[Pete1961]

Sometimes I need to take out welds, mainly to modify things - eg. side plates off a dipper off a farm backhoe got from a scrapyard - this is the basis of a log splitter. Also need to cut metal for projects & on jobs - I cut up & weighed in a couple of old rusty oil tanks the other week.
Looking for the most economic way to do all this. First thought was the Arcair K2000 if I could find one, beyond that it is a plasma cutter vs oxy prop or oxy petrol. I see a lot of cheap broken plasma cutters on ebay - makes me wonder about the reliability of these.
I also own a digging machine & sometimes need to cut stuff up on site (small jobs). Have a 9'' angle grinder, wondered about the life of diamond metal wheels vs usual abrasive - went through a few of the latter on the tanks job.

 

[davidjohnperry]

Gouging rods
9inch grinder
Gas cutting
It depends how you look at stuff
Time or cost
Each one neglects each other

 

[Rrunnach]

As I posted previous, Broco Exothermic is another option, it will cut through anything, even Granite stone.

Could not find any UK clips.

 

[davidjohnperry]

As I posted previous, Broco Exothermic is another option, it will cut through anything, even Granite stone.

Could not find any UK clips.

I've seen this done in some of the scrap yards I've always wanted to play with it but dads never wanted to buy it as we don't buy anything like rail cars or big iron for scrap. It's cool as hell but you need to.cover up well

 

[Rrunnach]

First induction was on land, then in a flooded drydock to gear up for a future em em em , project of removing portholes from a shipwreck Was funny at the time, loading our RHIBS at Kyle slipway with oxygen bottles, gennie, and a few metres of of oxy hose and return type lead for arcing up underwater. There were lots of curious onlookers as they waited for the ferry over to Skye, (Skye Bridge was at the early stages of construction) "are you working on the bridge was asked" AYE said us, as we motored off, in the opposite direction to the under construction bridge.

From memory, rods were expensive, see attached images of what was left over, which i show to my students, white tape is to me, electrical insulating tape, the oxy is basically directed down the orifice of the exothermic rod bundle.

 

[zeppelin builder]

I've seen this done in some of the scrap yards I've always wanted to play with it but dads never wanted to buy it as we don't buy anything like rail cars or big iron for scrap. It's cool as hell but you need to.cover up well

make your own!
1/2 pipe about 8 ft long with a ball valve at your end
pack it with 3 mm ms round bar 3mm tig wire is fine
heat the end with a burning torch till its melting and sparkling open valves
to oxy bank then open valve on pipe
pressure setting ??loads hi output gauge maybe 2 at once
the pipe is consumed too as well as the rods. but its very effective if not accurate . i watched a geordie lad (might have been a mackum or smoggy though ) cut up a subsea structure about 3 inch thick in denims and trainers only concession to safety was a knackered old visor


divers use a tube of tig wire with a makeshift connection for oxy and
electrickery source ( a dc welder )

 

[Memmeddu]

Broco BR22 or Arcair exothermic slicing torches are pretty cool .
My neighbor used them a lot (BR22) under water while working as diver for Saipem.
Essentially the rods are of 2 types
Land use or underwater use .
First ones are made out of aluminium tubes filled with steel rods (they should be 7).
Second ones are made out of copper tubes filled with steel rods.
Both of them have some sort of insulation tape wrapped on them .
Steel rods are shorter than the tube to reduce the risk of burning back the handle .

If it's possible to build one let's say DIY ?
Well with the right tools and knowledge it's just a tube.
Tube has to be at least 8 or 10mm in diameter.
Insulation tape as coating? It has the only purpose to avoid striking on the side of the electrodes
Ignition can be done using different methods (DC welder for sure might be the best option, heating torch, car battery, steel wool a the end of the pipe)
High flow oxygen regulator ,most likely set at at least 5 bar.
Torch handle it's just a fitting with a valve , connected to an oxygen line an electric source for the ignition

 

[Memmeddu]

130 psi or 9bar the pressure required
10mm or 3/8" the rod diameter

 

[Munkul]

Thing is, what are you going to achieve with a homemade exothermic? It looks rough as all get out, sure if you need to cut some very thick stuff up into scrap it makes sense but if you want a quality cut on something you're making, you want plasma or oxy-fuel.
If you're gouging, you want carbon arc, oxy-fuel, or plasma, probably in that order...

 

[Memmeddu]

Thing is, what are you going to achieve with a homemade exothermic? It looks rough as all get out, sure if you need to cut some very thick stuff up into scrap it makes sense but if you want a quality cut on something you're making, you want plasma or oxy-fuel.
If you're gouging, you want carbon arc, oxy-fuel, or plasma, probably in that order...

Does Exothermic cutting have other purposes than demolition or rough cutting?
Always seen them on emergency services or demolition applications.
It will cut everything , concrete too