CAW -- Carbon Arc Welding

I've been looking to purchase a welder for home use -- basically metal fence construction and various similar thickness projects. Many years ago,
back in high school, we used the old Lincoln AC-225 welders and it seems that they are a reasonable price, so I'm probably going to get one of them. I figure that if they could survive the abuse of high school students for that many hours each day, they can't be that bad. Plus, the price on a new one is only $269 over at Home Depot.
I would kind of like to have the capability to do TIG welding one of these days, but I'm not willing to spend that sort of money at present since my current needs do not require it. A bit of reading has turned up another type of welding -- CAW (Carbon Arc Welding). From reading the description of it, it seems to use a similar technique to TIG welding, minus the shielding gas. It also appears that the AC-225 can do CAW. Has anyone around here actually done CAW and if so, how do the welds produced from it compare with what you see from TIG welds?
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ago,
them.
new
There are two approaches using carbon arc and I'm not quite sure which you are referring to...
In the first, you use a contraption called an "arc torch." Many years ago, I had a Lincoln 180 amp "buzz box" and a friend had an arc torch which I borrowed on occasion. It held two carbon rods and an arc was struck between them. It worked well for heating and brazing, but I never tried actually welding steel with it. Think of it as an electric equivalent of an oxy-acetelyne welding torch.
In the other, an arc is struck between a carbon rod and the base metal. A jet of compressed air is then used to blow the melted metal away. This is the electric equivalent of an O-A cutting torch. The unit I saw was built for the purpose, but I suppose you could drive the rod with a buzz box.
Bear in mind a "small" problem with a 225 amp stick welder... The input power is 220 volts at about 60 amps. So, if you don't have a 100 amp power feed to your shop, figure in that cost along with the welder. This is why I ended up buying a Miller 170 MIG welder. I could run it easily off the 30 amp line I already had to the shop.
Jerry
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Jerry Foster wrote:

Actually, I'm talking about a third method where you have one lead clamped to the surface to be welded and have the carbon rod in the normal rod holder. You strike an arc like with normal stick welding but then feed a filler rod in as necessary. From what I've gathered, it's an older technique that you don't see anymore -- normal stick welding has pretty much replaced it.
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The reason you don't see it used for steel is that you'd get a horribly oxidized weld with no shielding gas or flux. The flux coating on regular welding rod supplies the shielding, with TIG you've got the argon doing the job. I've only ever seen the setup you've described used for "lead burning", where they do heavy lead sheet welding for like chemical reactors. You could probably stick something in steel/iron together that way, but it probably wouldn't stay stuck.
If you want a small semi-useful stick/TIG rig, take a look at the HF inverter item. If you get it at 50% off and with a coupon, it really isn't too bad for what it is. Doesn't do AC and is limited as to rod size, but, within its limitations, it works OK. You can lay nice beads with small DC rods. Another outfit that requires a 220 outlet. Don't expect to stick a steel building together with it, though.
Stan
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Home Welder wrote:

Right. A book I read recently has a lot about it. E. Wanamaker and H. R. Pennington, "Electric Arc Welding", 1921. This book gives the impression that a fair amount of arc welding was being done at the time with bare metal electrodes; carbon arc welding shows up ok compared to that, at least for welding thin sheet in flat position - "steel barrels, transformer cases, etc." Later in the book they say coated metal electrodes give better metallurgical outcomes, where strength matters.
Carbon arc cuts are wide and ragged. The authors say: "The width of a cut with a 300-ampere arc on 1/2 in. plate will be about 5/8 in. and the rate of cutting will be approximately 3.5 in. per minute; while with a 500-amp. arc the width of the cut will be about 3/4 in. and the rate approximately 6 in. per minute."
--
-jiw

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Home Welder wrote:

I see AC/DC buzzbox welders - brand name, mind you, made by Miller, Lincoln or Airco - for $150 or less in my area all the time used on Craigslist. I think you would be foolish to spend $269 on a welder you can't sell for $75. I know shiny paint is cool but that's too big a hit for this old fart.
I really recommend the older Miller Thunderbolt AC/DC models, the ones with detachable leads. I see those all the time used. I bought mine new in the days way before Craigslist and have never regretted it. I own 5 welders now and was using my Thunderbolt just yesterday.
The ability to run DC is critical for a stick welder.
GWE
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In rec.crafts.metalworking, on Thu 03 May 2007 05:30:46a, Grant Erwin

This kind of brings up another issue. I suspect that the cost of the consumables (rods, gas, etc) over time completely overshadows the initial cost of whatever welding methodology that you choose to use. As such, which is the most economical welding method for mild steel (e.g. metal decorative / security fences) projects? Since there are less moving parts, I would suspect that a typical stick welder would be cheaper in maintenance costs over the lifetime of the unit. For a given number of feet of welding, will stick type electrodes cost less than whatever the equivalent amount of flux core wire would be?
I have a couple of projects currently in mind for which I might need a welding machine:
1. A metal fence (i.e. 'wrought iron') around my home to replace the wooden privacy fence that is there currently. It will be made with either 1/2" square tubing for the vertical members or perhaps 1/2" square solid bar since the price is not that different. The horizontal members will be made from 3/4" square tubing with 1/16" wall. The posts will be 2" square tubing with 1/8" wall.
2. A very heavy gauge BBQ pit/grill/smoker. I am currently thinking that I want it made from 1/2" steel. This seems to preclude the use of a wire feed type welder since from the specs that I've read, they typically aren't used for metal this thick.
I have tried a wire feed welder once and did not end up with very nice looking welds coming from it. I have used oxy-acetylene for both welding and brazing and can produce acceptable looking welds with it, but I think that the gas costs would probably start adding up on a large project. I also ended up with more warping of the project that was probably acceptable.
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Home Welder wrote:

Stick is cheapest by far. To weld thin stuff like 1/16" you will need to use special light rod and make the electrode negative - this is something you can't do with AC. I personally haven't welded 16 gauge (1/16") steel this way but I know it can be done. Someone will chime in and mention what rod to use. MIG welders cost you $$ every time you turn around. Gas, wire, tips, it all costs. You only recoup that money if you weld for a living, because you can go so much faster with MIG that you save much more in labor cost than you spend in consumables. You want an AC/DC buzzbox. I had one for about 15 years and loved it every time I used it.
1/2" thick BBQ? Man, it's your nickel, but that sucker will have to be moved with a crane! And the material will cost you a TON of money.
GWE
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In rec.crafts.metalworking, on Thu 03 May 2007 06:36:44p, Grant Erwin

My rough calculations show that a lid that is 36" wide by 24" deep by 12" high will weigh about 250 lbs. Either I will need to counterweight it or I will get a very serious workout while BBQing.
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Grant Erwin wrote:

Way back before I knew better, I welded an exhaust pipe with AC stick - a butt weld, no less! Since then I have learned that I must have been *really* lucky. I would not even try to do it again. 1/16 is right on the hairy edge: there is a *very* narrow range between not joining and burning through. Very frustrating. Now that I have a MIG, I don't use stick for anything less than 1/8".
Qualification: I am a low-use hobby weldor. I don't get much practice and I'm sure that is a factor.
Bob
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On Thu, 3 May 2007 23:55:40 +0200 (CEST), Home Welder
<snip>

<snip>
A 300 amp commercial MIG will weld 1/2 steel in a single pass, most likely full penetration. Don't discount what a REAL MIG can do/weld. The 110 volt units have given MIG's a bad reputation. Just make sure you are sitting down when you price a new one. Good deals can had though on used ones, especially if you have 3 phase electric available.
--
Leon Fisk
Grand Rapids MI/Zone 5b
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Home Welder wrote:

We have taught ourselves arc welding. And it was quite a learning curve. As others have written before you start 1. before buy any welder make sure youve enough power coming into your place to run the machine you plan to get. 2. go to the Miller and the Lincoln web sites and read all their tutorials. 3. If youve access to old book shops try and find any welding books from the 1930 to 60's. There much more helpful with using old equipment.
Now onto your projects. 4. A metal fence is fine till youve to maintain it. It will need constant painting, unless your in a very dry part of the US. A wooden fence is easier to maintain. Just a coat of wood preserver we have whats called creosote, a coal tar derivative, nothing finer to prevent wood rot. used by all our telcos for their poles just slap on .every couple of yearsand it will last for 25. Your metal one wont. 5. Whats the span between each upright? and are you going to set it in concrete? 6. Youll need as you say 2by 2 uprights, for your cross pieces youll need 2 by 1 not 1 by1. id suggest 3/4 box for the upright railings. If solid youll find it will droop in due course. Dont try carbon arc. stick with stick to start with.
Make up some test pieces before you decide on what you want to make for real. Do all your welding down wards, on the flat to start with. IE start with the easy way first. Make sure you have a proper helmet and are fully covered to avoid UV radition burns. Never weld without a helmet. Yuoll getarc eye which is very painful and can cause eye damage.Your eye lense focuses the arc !!! onto the retina. Keep every one else away from your welding. Particularly kids and animals. Wear safety boots. Youll need a angle grinder to clean up the metal where your welding and to remove welds you dont want. A chipping hammer to remove slag. Some engineers chalk to mark up. a tape obviously And finally for the moment, lots of clamps to hold everything together till its welded and some trestles to work off. and lay out the work. Think how you plan to assemble your fence. Generally you bolt eash section to the uprights just in case you need access for some reason or other. Think how you plan to make all the bolting joints. Youll need to drill lots of holes in plate say 3/8th to 1/2 in size. hard to do by hand. When making these mark out, center punch in say a 36in strip, drill all the holes then cut of on your power saw. Thats what we do anyway. Grind up all the sharp edges. Better to have a leg vice outside for all this, and make shure your upwind of the grinding. If you dont when you blow your nose later youll get it all come out black. Have fun. Have you a neibour? who might object to all this heavy engineering ? Just a few thoughts. Ted. Dorset UK.
.
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In rec.crafts.metalworking, on Sun 06 May 2007 03:17:53a, ted frater

I learned *many* years ago on a Lincoln AC-225 back in high school. I might not have necessarily produced the prettiest welds, but they were structurally sound. Well, sound enough that my jack stands didn't fall on me. ;)

My garage is detached and the power for the house first enters the garage, so this should not be a problem. If I don't have space in the breaker box, I suspect that it won't be too big of a deal to feed a new box off of the original supply lines.

In my neighborhood, the only choices for fences are cedar picket and metal. There is a large field and small lake behind my house and I would like to open up the view a bit.

I'm inclined to go with 8 ft between the uprights (or at least one set of the uprights) so that I can move a vehicle through there if necessary. I don't want to put a permanent gate there, but being able to remove a fence section easily might be desirable.

I was considering an attachment method of bending the ends of the horizontal pieces 90 degrees downward and welding appropriately sized pieces of square tubing in the 2" posts so that the fence sections could be lifted and removed. I'm thinking that the weight of the fence sections should keep them secure. This should keep me from having to drill a lot of holes with a hand drill.
Another possibility would be to use two horizontal pieces near the top and two near the bottom and welding a short vertical piece between them and a couple of inches lower so that it would provide a supported pin type mechanism to fit into two pieces of square tubing acting as receptacles that are welded to the 2" posts. Although this uses one more horizontal piece that the design which I had originally considered, it might very well safe time since I would not be needing to try to do precision tight radius bends.

A long as I don't start early or continue after 10pm, it's unlikely that anyone would complain. If I do it during the week during normal business hours, it's unlikely that anyone would even be around to complain. ;) Well, except a couple of retirees, but their hearing is probably shot anyway, so they wouldn't notice.
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On Thu, 03 May 2007 03:30:46 -0700, Grant Erwin

I agree with Grant nearly 100%. Buy a decent used one. Ive sold the ubiquitous AC-225 from $75-150.
I do disagree in part that a stick welder (home style) needs DC.
Gunner
"If thy pride is sorely vexed when others disparage your offering, be as lamb's wool is to cold rain and the Gore-tex of Odin's raiment is to gullshit in the gale, for thy angst shall vex them not at all. Yea, they shall scorn thee all the more. Rejoice in sharing what you have to share without expectation of adoration, knowing that sharing your treasure does not diminish your treasure but enriches it."
- Onni 1:33
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It's NOT a welding tool. The lack of shielding gas is a big problem for welding. "Welds" would be despicable, not at all comparable to tig. Use plain old flux coated electrodes and stick weld if you want to weld with the tombstone - that's what the welder and electrodes are made to do.
The carbon arc torch is used for heating and brazing (with flux and flux-coated rod), in my experience and training - it can keep you from needing to pay rent on gas bottles if your heating needs are limited. Gas is generally nicer for that sort of work. I have successfully brazed things using a twin-carbon torch in welding class years ago - but I can do a much better-looking job with OA. Given the choice of the two, the carbon arc torch would never get used. However, the carbon arc torch does not come with demurrage, regulators that need to be rebuilt, etc...it can hang on the wall in the shed for years, be dragged out and used for 5 minutes, and go back in the shed for years, so long as the shed is not too damp (the copper on the carbons will corrode in storage if it is).
--
Cats, coffee, chocolate...vices to live by

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wrote:

It IS dang nice as a single stinger for gouge-cutting badly rusted metal. I once cut apart an 1800gal propane tank (yeah... I know...but we did it by the numbers, purge, water fill, etc.) with only carbon gouging rods, and it went lots quicker than with a cutting torch. I did use a whole box of rods, but they're cheap -- cheaper than two bottles of gas.
It is NOT as neat as OA cutting or better, plasma.
LLoyd
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Home Welder wrote:

You strike an arc using the carbon rod like you would a standard stick. Then feed filler rod. It works but it doesn't leave a nice pretty weld.
I have a small spotweld gun that uses the same principle. You hook it up and pull the trigger to start the arc. Wait a couple seconds and the weld is done. Pull the trigger all the way to break the arc.
--
Steve W.
Near Cooperstown, New York
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