Carbon arc torch

[scooter]

Gday

I bought this doovah from Mitre 10 about 8 years ago. It's a handpiece made from plastic tubing, with two cables coming out one end that attach to the electrode holder and the earth clamp of an arc welder.

Out of the handpiece there are two brass coloured metal rods that each have a holder for copper covered carbon electrodes. The holders orient the rods in a "V", and the handpiece has a thumb slider that moves the rods closer together.

To operate you put the electrodes, or carbon rods, in the holders, attach the cables to the welder, & looking through a welding mask the thumb slider moves the rods together until an arc is struck between them. As soon as the arc is struck the rods are slid apart fractionally until a steady arc is maintained. This takes the form of an electric "flame", when the gap is correctly held the flame is steady & makes a sort of purring sound.

The flame is extremely bright, and it is a very hot heat source. It can be used for brazing, heating parts, etc. It is used in industry in combination with compressed air for gouging of steel, cast iron, etc.

My question is, does anyone know where these rods can be sourced. I have a couple of the original set left, but will need to track down some more at some stage. I was thinking welding supply shops, anyone have any other ideas.

Will take some pics & load up later.


Cheers...................Sean

[Grahame Collins]

Hi Sean
How many boilermakers do you know?

If any ask, one to get some samples of carbon arc or Air Arc electrodes as they are the same construction copper coated carbon rods.
A caution is that they come in AC and DC varieties so one type may no necessarily work as well as the other.

Also specify the diameter.

Another source will be a dedicated welding suppliers shop like Global welding though I am sure there are others in the phone book. I am sure they are too sophisticated for places like Bunnings.

Grahame

[China]

I have one of those in the shed must be 30 yrs ago that I bought it, I've tried to find rods for it but the only ones they make now are to short

[hughie]

Sean,

Check it out with your local welding supply shop. IE Gasweld etc. It will depend on the dia of your rods as whether they are still available.
The carbon rod set up or Arc-air is quite common in heavy industry. Boiler shops, mining etc.

http://www.discountwelding.com.au/product/GOUGING-CARBONS-D.C/111.html

is this what your after?

[scooter]

Thanks guys. Will keep looking around.

Edit: Thanks hughie, they look like the beasties, I note they're DC though so will ask whether that matters. Will try a welding supplies shop in Dandenong next time I'm down there.

[mikm]

Hi Scooter,
Did you manage to find any electrodes? Your description sounds exactly like the "plasma torch" I inherited from my grandfather. I used it years ago while he was still alive and having found it quite interesting back then, would like to fire it up again for a new job on the go. I have a couple of electrodes around, but if it's as handy as I remember, I'd like get some more.
Cheers,
Mick

[joe greiner]

I have a vague (very, very vague) recollection of seeing a DIY apparatus like this in a "Popular Workbench"- type magazine about 50 years ago. IIRC, the carbon electrodes were salvaged from the cores of dry cell batteries, size C or D. Present-day batteries might have different construction, but it might be worth dismembering one to see if it's suitable.

Joe

[mikm]

Joe,
This reminded me to take a look at the 1957, 12 volume "Popular Mechanics Do-It-Yourself Encyclopedia" I have. I (and my dad before me) spent years as a kid reading and re-reading all 12 books cover to cover. Great stuff.
Anyway, it describes the construction of an arc welding torch employing carbon electrodes - driven by a multi-tapped single winding from the mains supply :o. Isolated transformers were obviously for la la's back in the old days!

I thought this design used battery rods as you described, but it simply calls for a pair of "1/8th inch carbons", so I assume they were commonly available.

Having said that, the arc torch I have uses copper jacketed rods as originally mentioned by Scooter. All freshly inspired by this thread, I fired it up yesterday to heat some steel to bend up for a bracket. It wasn't too flash at heating up 75 x 10 mm flat bar to read heat in a hurry, but it has no problems on smaller stuff. Within limitations, its not a bad poor-man's oxy substitute, really.

Its great fun to use, but I kept looking over my shoulder for a Jacobs Ladder and an assistant called Igor for some reason...

[graemet]

My first job was in a machine shop which made arc lamps for movie theatre projectors. Those lamps used copper coated carbon rods which were also utilised in those plasma torches. They were slightly different diameters for positive and negative polarity, as one would tend to burn away faster than the other if the same size. One had a pointy end and the other was cupped, the arc was a cone shape, and VERY bright. A gearbox drove the two electrodes together as they burnt away. The electrodes were about a foot long and about 1/4" in diameter and would last the length of a feature film reel.
If all else fails, a theatre supply company might be able to help, - I guess they would still use those lamps for big projectors.
Cheers
Graeme

[joe greiner]

Now that I ponder a bit more, I have an even more vague memory of my best pal from that era (and still) making one from battery cores. I'll e-mail him with the subject of "Memory Test" but his memory may be worse than mine. Wait and see.

That said, Google [carbon arc torch] got several hits, including this one: http://www.lindsaybks.com/bks8/meador/index.html I probably have one or more of the books on the carbon arc torch, but several of my books are still in moving boxes. I don't know if Lindsay ships to Oz, but many of their books are also available in Oz bookshops and libraries. BTW, Lindsay's catalog is a hoot to read.

Even after all that, I might just have scrambled memory, with all the discipline of a fratority toga party.

Better grab any arc lamp rods you can find. That type projector is rapidly being replaced with digital contraptions.

Joe

[joe greiner]

My friend's memory is only slightly better than mine with respect to the battery cores (maybe right). But he also gave me a link for replacement rods on a spot welder: http://www.eastwoodco.com/jump.jsp?itemID=1230&itemType=PRODUCT

My friend thinks these are carbon rods. It's unclear whether they ship to Australia, but there are most likely similar tools and suppliers downunder.

Joe

[mikm]

Nice work Joe,
As far as I can tell from the photo, they look to be exactly what I am currently running out of. Nice to know they are a spot welder consumable and so should be fairly easily obtainable.
Thanks for that.
Mick