Carbon arc torch

[Kernopelli]

Anyone got an opinion on using one? I never thought much about it until a friend mentioned that he had been using one to heat large frozen nuts, bend metal, minor cutting, etc.....about 90% of what I use my small O/A setup for. Problem is, with 2 sons that are always out working in the shop, every time I need to use my torch, I'm out of gas or don't have enough to finish what I'm doing. After talking to my friend and looking around on the net, I think the carbon arc is a cheap way to to do much of what we use a torch for and save the gas for the rare times I actually need to braze something. I have found several torches for about $35 or you can simply make one for little or nothing and the local welding shop has rods for $10 a box (3/8 x 12") I would like to hear from anyone who has used one about their experiences. What is the reason nobody seems to use them any more?

 

[Kays Supply]

My experience with one was many years ago. I will try to remember what I can. The first thing is they are pretty crude as far as results. The main reason we used one at the cannery I worked at was to cut cast iron and stainless steel. It took quite a bit of grinding to make the cut usable for a close fit. It also could cut steel that was very thick. That is all I remember about using one. Hope it helps.

 

[blacksmith]

I have used one to heat metal because I do not have a gas setup. I have welded with one also. It takes some practice to use it. The only cost would be the carbon rods which are used up when in use. The holder swings two carbon rods together forming a V and the arc is generated. The "flame" or arc is used to heat or weld material. I welded 1/32 thick material that had a crack in it using some mig wire. I have a tig torch and mig outfit so I only use it to heat something up. It is attached to an AC welder.

 

[Kays Supply]

The one I used had one rod and you hooked a high pressure air line to it. You used the air to cut with like a O/A rig.

 

[cup149]

I have one that I use when I need to bend a piece of steel. Craftsman brand that I use with a Lincoln tombstone welder. I use it at 70 amps (100% duty cycle), and make sure to wear protection from the UV rays. I don't need it very often, so wouldn't make sense to have gas cylinders sitting around. Never tried to braze with it, I guess it would work, but at 70 amps, the flame (arc) seems a little soft so thicker material takes a while to heat and you can't direct the heat like a gas torch.

 

[Travelover]

I have one that I haven't used for a long time. Back before I had an O/A set I used to use it to heat steel and do some brazing. Once I got a heck of a sunburn from using it without protecting my neck and arms.

If you mostly want to heat something to bend or braze, or to loosen a frozen joint or nut, it is a great way to do it without a torch. They are pretty easy to use, too.

 

[bigdad]

I have an O/A setup, but I don't like buying the gas. I use the Carbon Arc torch when I want to braze something. I must admit, it isn't pretty at first, but you get the hang of it. The trick is keeping those rods the right distance to maintain that sweet arc or electric flame.

Like the fellas say..... make sure to cover up and use correct eye protection.

 

[BHD]

there are two basic types of arc touches, there is one with two carbons that kinda work like flame torch, that makes a arc flame.

and there is the air arc, which is kinda like a cutting torch, Air carbon arc cutting - Wikipedia, the free encyclopedia
http://www.thermadyne.com/arcair_pdfs/89_250_008.pdf

and the torch has two holders with a carbon in each of them and you touch the carbons together and adjust the arc for your needs as well as the amps, and basically produces a flame arc,

 

[svcguy]

It seems we are talking about two different things here. Air arc and carbon arc torches. I think the one you are asking about is the Twin Carbon Arc Torch. Carbon arc torches are handy things, but not too common anymore. I think they have fallen out of favor for a couple of reasons. At one time a torch setup was expensive and the hassle of oxy / acet bottle was too much for rural shops. Electric welders were pretty common on farms and carbon arc torches were a cheap substitute for a torch setup. They give off an excellent, localized heat and in the hands of an experienced user they are a great tool for heating, bending, brazing, etc. The problem with Twin Carbons is they can burn material quite easily, so watch your metal carefully. They are great for heating flat stock, as you can get a thin band of cherry red across metal and get very tight bends on it.

You move the carbons together, then apart until you get a nice arc which emits a soft buzz. Here is a great site that shows you how to build one:
Using the torch

Keep in mind that when you purchase carbons, they make special "cored" carbons for AC welders. Many of the bad experiences with Twin Carbon Torches are from attempting to use DC "solid" carbons with AC welders.

 

[svcguy]

Forgot to mention a Twin Carbon Arc is great for rusted bolts, but not how most people would think to use it. If you pinch the carbons on opposite sides a frozen nut until it smokes from the threads, the nut comes off easily. The reason is that the current runs through the nut, but the bolt is insulated by the rust. Bolt stays cool / the nut expands.