Anybody have experience with single-carbon-arc welding on steel? I gather it was the first arc welding process developed and very quickly replaced, but would like to know if it has a place in "hobby" welding, where quality of weld matters, as does cost, but speed isn't so important. Seems to me it should resemble O/A welding with a reducing flame. Stick welding never much appealed to me, especially in small work, because the heat and filler can't be controlled separately.
Are you talking about a carbon arc torch - two sticks of carbon and an arc between the two? Used much like a oxy-acet torch for brazing, but difficult to control the heat.
Or some sort of single carbon and strike an arc to the parent metal? Heat control probably similar to stick welding and you need to add filler.
As you say, "developed and very quickly replaced", there was a reason for that.
User Bp fired this volley in news:lf942o$e8i$1 @news.albasani.net:
Bob, in reverse order:
OF COURSE the heat and filler can be controlled separately with stick welding! That's why we have 1) adjustable current welders, and 2) different-diameters of filler rods! I've been present for stick welding demos with 1/2" rods and 22AWG rods. 'Just depends on how fine a control over current you have, and your skills!
Now on the carbon arc bit... it's not abandoned -- there are just better, cheaper, less smokey ways to get that much heat in one spot. All through the 1960s and into the 1970s there were a rash of "small hobby welders" sold that touted to do "real welding and brazing from a wall outlet!"
Yeah... They consisted of a large air-wound Nichrome resistance wire inside a convection-cooled cheap aluminum breadbox chassis, and two sets of cable ends. The resistor box looked all the world like the resistor enclosure on an older style electric golf cart -- may have even BEEN one, re-purposed!
The two electrode sets: One was a munchkin's version of a standard ground clamp and electrode holder for AC stick welding. The other was (correctly) called a 'carbon torch', and consisted of a two-wire holder with mounts for two gouging electrodes. There were no provisions for accurately adjusting the spacing between electrodes while they burned, so you got about 30 seconds of heating from the torch before you had to loosen a wingnut and re-adjust the spacing on the carbons' tips.
The welders were pretty useless, but served to teach me that the carbon torch was a common item once. My dad taught me how to (quickly!) braze with one, and I never lost that. They're still around, but they make a LOT of smoke and metal fumes as the copper shroud over the carbon burns away. There are cleaner, better ways.
I recall my dad using the carbons from a pair of D cells and jumper cables from a car battery to repair a solder joint on a starter/generator commutator on my Uncle Bill's boat motor . We were camped at Palisades Reservoir near Idaho Falls Id. , it broke and the boat no go . We kids wanted to ski ... and Dad and Bill wanted to fish .
I have the Lincoln carbon arc torch. I've only used it as a 2-carbon torch, for brazing. I've never tried to weld with it, and I'm not aware of it being used that way. I power it with my buzz box and given that I have the buzz box, that's what I weld with. I'd say that you'd need a constant current power source for it, so why not stick weld?
Yes, that's it. Size the electrode and current to the base metal thickness for a stable arc, add filler as needed. Rather like gas welding.
That's the clue I'm looking for. If it was replaced because it's slow that's ok. If it was replaced because it's hard to control, especially for thin (.062 material) the process won't be of much interest. If it makes brittle welds that's another handicap, but a reducing O/A flame isn't a problem if one works briskly with low carbon filler. (And isn't building an airframe!).
Copper clad electrodes seem likely to cause weld contamination but bare electodes appear to be available for fussy gouging jobs.
AWS handbooks would be informative but rather pricey outside a library. I'll check the local libraries.
In nearly every instance when things are replaced, superceded, by another technique, it happens because the later techniques is better, in some manner. Faster, stronger, easier, cheaper.
You seem to intimate that for some reason oxy-acetylene is not to be used to build an airframe. Strange.
You see, I qualified with oxy-acetylene when it was the designated method of building, or repairing, aircraft airframes and years later welded a bloke's home built airframe which was later subjected to an airworthiness inspection. certainly the CAA/FAA didn't seem to have any objection to using oxy-acetylene :-)
The real question is, "why bother"? One can easily weld with Oxy-Acetylene, Stick, TIG, MIG, or any of the submerged welding techniques. Why would one want to bother with carbon electrodes?
Agreed. Cheaper is my keyword. Easier is next. Stronger is nice, but this isn't a critical project. Faster does not matter.
O/A with a _neutral_ flame is understood to be acceptable. I did a bit of auto body work with a reducing flame (it was easier to carry a puddle on thin material) and had trouble with weld cracking. Apologies if my meaning was unclear or interpretation mistaken.
Understood, but a carbon electrode seem likely to produce a carburizing atmosphere. Perhaps not to the extent of acetylene, but still reducing. Then again, it might be worse.
For my part, cost, and curiosity 8-) Thanks for reading,
That is one of the things you learn when becoming a welder :-) Somewhere I have notebooks filled with information about rods, flame, fluxes, parent metals, etc. I've probably forgotten all of it but that is what you had to know.
But why the need for a carbonizing arc? The usual aim is for a neutral flame, if oxy-acetylene welding.
Well, curiosity is a good reason, but cheap is, perhaps a bit far out. After all, you'll need some sort of a power supply to drive that carbon arc; hopefully a variable supply if you want any control of the arc, so you might as well start out with a commercial welding set :-)
I'd like nothing better than a commercial welder, but I can't justify the cost for what is essentially a hobby. A nice Miller just got away from me and I will keep looking. In the meantime, an improvised scheme that works within limitations is an entertaining project. I played with carbon arcs as a child but never thought to try welding. Then I learned O/A well enough to do useful auto repairs and stick well enough for heavy (1/4") material. That equipment is long out of reach now. TIG is the obvious next step, but that's a serious investment.
A carbon arc might be a useful compromise between the power of stick and the control of O/A, provided the chemistry cooperates, using an improvised power supply. If I can carry a puddle that makes a not-too brittle weld in .050" mild steel it would count as a success, so the goals are fairly modest.
Err... You talk about an improvised power supply that will hold an arc using a carbon rod, but stick welding, which is holding an arc with a metal rod, is a problem?
As an aside, you can weld considerably thinner metal than 1/4" with an arc welder.
At low currents it seemed to be. I could carry a steady arc with the output of an old automobile generator (gen, not alt) using heavy pencil leads (graphite) as electrodes. The current was probably in the low tens of amps. Metal electrodes stuck badly.
I'd expect an alternator to work considerably better (more voltage, self-limiting current, which is what I have and plan to try.
For a good operator with modern equipment (and maybe even not-so-modern) that's no doubt true, but at least for me thin electrodes and low current always spelled trouble. Carbon was vastly easier to strike and maintain. Current sufficient to keep a metal arc going always seemed to make for faster work than I found comfortable. That is a fault of the operator, but I'm stuck with him...8-)
In a way, it seems I'm looking for an electrical version of O/A: Heat independent of filler rate, perhaps more power density, no tanks and (above all!) minimum capital cost.
But, with a consumable electrode, current controls power, and power controls melt rate in both electrode and workpiece at least for AC. DC one can shift the heat bias between work and electrode, but beyond that we're stuck, I think.
I'm willing to advance to the era of inductive ballasts 8-)
That sounds close to what I have in mind but using DC instead.
30 seconds isn't much time.
Ok, that's the key I'm looking for: What was wrong with them?
That's helpful information. I've heard of twin-carbon torches but never seen or used one. How does the locality of heat input compare to an oxyacetylene flame? Was there a problem with embrittling steel with excess carbon input? Copper seems to make mischief in ferrous work, but can be avoided. Was it hard to avoid overheating the workpiece? Thanks for reading!
User Bp fired this volley in news:lfjkm8$4om$2 @news.albasani.net:
You localize the heat by pencil-pointing the electrodes. That was ANOTHER chore with that $19.95 "home welder", because it held 3/16" gouging rods, and they were really too big for the sort of work one could do with that toy.
I never did anything but really quick brazing on sheet metal with it, so I have no idea about the tendency to transfer carbon to the metal. FWIW, though, CO2 is used as a shielding gas for MIG, so I'm not sure that carbon vapor and the CO2 that would form around the arc would be much more damaging to the work than flooding a metal-arc with CO2. At least with the carbon torch, a metal spray wasn't flowing through the gas!
Well, as for equipment, I used to do it with a simple transformer welding machine :-) But you can easily buy 1.6 mm electrodes which can be used to weld some fairly thin metal, and I knew a bloke that claimed to have some 1 mm rods, although I never actually saw the electrodes.
Which seems to be saying that your weld puddle will have no protective atmosphere and be fully exposed to the air. I have this feeling that your weld beads are going to be somewhat less than an ideal composition.
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Other than (or going the horrible fright route, perhaps) your last criteria of cost, you are describing TIG welding.
Some (many?) stick welding supplies that can take a foot pedal (or thumb control) can do "touch start" or "lift start" TIG (where you touch the electrode to a copper block and lift it, rather than have a high-frequency start.) Or they can be used as power supplies to a TIG Box that has the current control and/or high frequency start built in.
In the other direction, all TIG supplies make super-quality stick welders.
This is really the core question that wants an answer. My (possibly mistaken) hope is that the carbon evaporated from the electrode will scavenge oxygen leaving an atmosphere of CO. If this does not happen the whole scheme won't work, which is the knowledge I'm seeking. It may have been the reason for the original abandonment of the process, but nobody has said so yet.
An O/A flame is CO mixed with hydrogen, far as I can tell free hydrogen makes more trouble than it fixes at least with ferrous alloys. On that basis a hydrogen free "flame" ought to be better for welding.
In all respects I agree with you. When "horrible fright" was selling inverter welders for ~$150 I was sorely tempted, but managed to resist. Good equipment will cost ten times that much unless I get _very_ lucky. In the meantime I'm trying to learn what I can.
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