7018 on AC, please help me!

Can you guys please help me understand? I ran some fillet welds on AC this morning with Lincoln's Excalibur 1/8-inch 7018. Ran the first fillet at 145-amps, with the rod right out of the oven. Every pass started without any problems, one maybe two taps on the rod and off we went. Never once did I get the impression the rod wanted to die, I even jammed the rod right into the puddle. I ran every one of these passes just like I would on DC. Honestly the only difference I seen was the noise! But I did notice the puddle doesn't wet out as much as on DC.









This pass was run with a cold rod, never seen the inside of a rod oven. I ran it at 150-amps. Notice it didn't wet out as much as a rod out of the oven?

Did you break the coupons yet?

Didn't think of that!
Wouldn't do any good anyway, there is weld on both sides.

Hello Puddles,
I cut my welding teeth on 7018 A/C.
On a downhand-fillet pass, you will notice the rod has a tendency to have a center crown.
The A/C splatter may be a reason for that, but you will also see a difference on overhead welding. You will have drop the heat as you know, but you'll have to chase the sides of the weld as well, to make it look good.
Guido.

Try and run the rod at 120 amps. That was what I was trying to do with my project. Take some pictures of the results. In two hours of welding on my project, I "might" have had two beads that looked as good as yours. I"m impressed.

I started at 130-amps, way too cold, went to 140, still didn't like it, 145-amps seemed somewhat OK, but still didn't like the crown. This was run on a Miller inverter welding machine.

As of now, I"ve got about 2 pounds of those "damn" 7018's left. I think I'll head up to the shop and see if I can change their adjective.

I generally have pretty good luck with 7018. There is a slight chance I've run a rod or two more than you tho.

Boy, I wish I had about half the stock that you guys burn up on 'welding tests'.

Brad

Your inverter would be a lot easier to use than a low end transformer. An Idealarc 250 on AC would be easier than an AC 225 as well. They used to make industrial AC only machines(TM series Lincoln in AC or AC/DC versions) for large rods because of arc blow problems. Do you still have your old entry level Montgomery Wards? AC/DC welder? Try the AC on that.

I think because you used your Dynasty is why the weld didn't wash out better. It has lower OCV volts because it's mostly designed as a TIG welder. I would highly suspect that's why some welders have said they don't like a Dynasty as a stick welder.

The Dynasty has two settings for OCV. Low and High, low is between 9 and 14 OCV's. I keep it set on the high setting which is 95 OCV's. The digital read out only says 84.9 OCV's. The manual says leaving it on the high setting may not be acceptable to some weldors, while Tig welding, I never could tell the difference myself, so I leave it on the high setting.

That Montgomery Wards machine is so far back in the barn it would take a week to get to it. Anyway that Miller Gold Star, (330A/BP) is right next to it, if I was going to drag anything out of the barn it would be the Gold Star! :wink:

That's interesting. How does the Dynasty compare when running 7018 on DC compared to the V-350 or your other machines?

The Dynasty sucks with SMAW! It's not even on the same planet as the 350-Pro! In fact, that little Everlast machine is a way better SMAW machine than the Dynasty!
The Dynasty really shines with Tig aluminum tho! 8)

There has to be something different in the volt amp/curve, inductance or something to make such a difference between the TIG inverters and the stick/MIG inverters. It was probably easy to strike and maintain an arc because an inverter is almost like a high frequency in the first place.

I was taught the 7018 is strictly a DC rod if you want both the 7014 is the rod to use. Check the welding rod book. We use 7018 all the time but DC only. I'll try to find my Hobart book and post.

I have a Lincoln Weldirectory right here in my hand. It says Jetweld LH70, Jetweld LH 73, Jetweld LH 75 MR, Jet-LH 78 MR, all 7018, all can be run on AC, or DC+.

7018 was always a DC+ or AC rod. 7018AC just makes them a little easier to use on an AC only machine. Hobart had the first 7018 AC and they were real easy to restrike an arc with. I tried them on my DC generator but they got porosity for some reason on DC.

Puddles,
those are some pretty looking welds, especially the ones on the round tubing. Great hand control, IMO. I'm getting better with practice but definitely a newbie compared to you guys. I don't think I could make a long pass on your test piece look like that to save my life. I usually do what you've suggested in the past to minimize distortion and weld in short stretches, alternating sides. That works great as I've fabbed some decent size framework and held dimensions without much twisting, etc. Problem I have with that technique is getting my "restarts" to look continuous.

couple of "newbie" questions:
- Did you weld that piece in 1 continuous stretch?
- Only way my welds look like that is if I take a wire wheel to them afterward. I'm using mostly 6011 on a Lincoln 225AC buzz-box. Does 7018 look like that prior to cleanup? I bought a small box of 7018AC that I'm planning to try someday. It's staying sealed until have a project that I can use most of 5lbs on since I don't have an oven.
- I use an old non-auto-darkening helmet and am a little inconsistent on starting my welds where I want. Once the arc lights up, I can usually "find" my spot but it sometimes makes the final weld look like a drunken sailor wandering down the pier. Would an auto-darkening helmet help much in that or I do just need a steadier hand?
- As I've been doing more and more welding on larger projects, I'm concerned about pushing the duty cycle on the buzz-box. I try to be aware of it, but sometimes I lose track of time and wonder if I've let the tombstone set long enough between arc-strikes. Since I've been doing stuff mostly in the 90-135A range, I figure I'm in 40% duty cycle range most of the time. Is it better to let the fan run, i.e. leave the box on between arcs or shut it off?
- Are there warning symptoms of getting close to duty cycle limits or do you just fry the thing when you exceed it? Fan air seems to be pretty constant even when I think I'm pushing the little guy.

(quoted from post at 02:56:23 07/13/11) Hobart had the first 7018 AC and they were real easy to restrike an arc with. I tried them on my DC generator but they got porosity for some reason on DC.

Click to expand...

Dave, obviously you need more practice with 7018AC.
Get out there and burn some rod. Remember, practice makes perfect. :wink:

Puddles, as always your welds look great.
And we always appreciate your good advice and pic's.

Puddles, this question has probably been asked before but how many welders do you have? Do you collect them or just have multiples because certain models are better for certain things. I don't imagine I'll ever be good enough to see a big difference between welders so maybe that's why I don't know why one would need so many.

JML755 if you're talking about welding the pipe in one continuous stretch? No I start at the bottom, 6-0'clock and weld as far as the rod will allow, feather the stop out with a die grinder. What I do is start about 1-inch in front of the stop, and drag the rod back to the stop, let the puddle fill then take off.
I don't like auto darkening hoods, just too many years with the old school hoods I guess, but for a new guy I think they'd be a very big help.
My Dynasty has fan on demand, I never shut it off with the fan running, with the OCV's turned up the fan comes on more than when the OCV's was on the low settings, sometimes if the fan hasn't turned on in awhile I'll wait until it makes a cycle, then turn it off. I never turn any of my machines off soon as I'm done welding, I'll let the fan run a few minutes before shutting them off. Not saying my way is the best, it's just the way I do things, and I've been doing it my way for a lot of years, and it's worked so far.

Here's a picture of 6-0'clock on a pipe. Started at 6 went to 9 then to 12, feathered the start with the die grinder, started the next rod about 1-inch in front of the ground out start, drug the rod back to the ground out area let it fill then went to 3 and onto 12. Could have spent a little more time with the file to take the low areas out tho.




Thanks eastexan, I try to pay it forward when I can.


Inno I think I have 11 or maybe 12 welders, I'll have to count them. Yeah I have a sickness, I need help! :lol:

An auto-darkening helmet helps enormously. Try a Harbor Freight a/d helmet which you can buy for as little as $35. I've used them for years and think they are great, cheap helmets. The lens provides UV protection equal to DIN 16 (shade 16) even in the clear state which effectively makes the issue of whether you should trust your eyesight to Chinese optical electronics a moot point.

Lincoln AC 225 buzz boxes (and their AC/DC equivalent) have a 20% duty cycle at all settings. The duty cycle does not increase as the amperage settings decrease. This is because they physically use a different conductor from the transformer to each setting on the dial rather than the same conductor with a movable shunt through the transformer as, for instance, the Hobart Stickmate does. The heat buildup of the different sized conductors is the limiting factor in the duty cycle.

The good news is that Lincoln buzz boxes are famously so robust that many, many users simply ignore the duty cycle with no damage to the welder and, apparently, no shortening of its life span. What is often the case is that the user won't have a 50 amp outlet available and has to use a 30 amp (dryer) outlet. Then the duty cycle of the electrical system circuit breaker is directly related to the output of the welder (well, inversely related would be more accurate.)

It's good to be careful, but you're probably worrying about this more than you need to.

Stan

You'd notice a huge difference comparing some welders, especially going from a low end AC machine to a better DC machine.

Hobart stopped making the easy to restrike 7018AC. I bought it to see if it really did restrike easy. It did, you didn't have to knock the slag off the end to start welding again. There had to be a really good reason to stop making an easy restriking 7018, like maybe because it got porosity if used on DC?

Thats new to me, stan...

I was always told that the little circle around the "75" amperage setting indicated that below that, you could run the welder at 100% duty cycle.

Stops and starts take a little practice to make it look like a continuous weld. On a really good welding machine, sometimes you can start the arc right at the crater of the previous weld but usually you strike your arc a little ahead and once it's established you move back to the crater and weld over where you struck the arc. On root passes you strike the arc on the previous weld and move forward to the crater. It all gets ground clean anyway.

If you're using 1/8" rods or smaller, don't worry too much about the duty cycle on the welder. It might even have a high temperature cut out to protect it. You'll be able to smell if you're burning a welder up. It's a good idea to leave the machine turned on for several minutes after using it. It's only the fan running. In big shops, you usually turn the machine on in the morning and don't turn it off till the end of the day, even on lunch break. An auto darkening helmet would be a big help to see what's happening before you strike an arc. With a conventional helmet, you have to adjust the pivot tension where you like and practice giving your head a quick nod to bring it down while holding the stinger steady at the same time. Once you get that figured out makes it a lot better than manually putting your helmet down.

7018 should look pretty nice as welded and the slag should come off pretty easy in most cases. The big exception is in deep groove welds where sometimes you need an air chipper to get the slag off. Your 7018 will be fine as long as it stays dry. The plastic rod containers are what most rig welders use to keep their rods in.

The 75 setting had 100% duty cycle for pipe thawing or using a carbon arc torch. Despite what Lincoln says, I think they have a higher duty cycle than 20% on lower settings.

You're right, Lanse. I forgot about the 75 amp setting. Happy birthday.

Stan

You're right, Dave. As I said to Lanse, I forgot about the 75 amp setting.

As far as that welder having a duty cycle higher than 20%, I agree with you that it's actually higher. Practically speaking, there's a huge amount of evidence that it's higher because of all the users who tell about using it hard with no regard to the stated duty cycle. If you open one up, though, you'll see why it doesn't have an increasing duty cycle at decreasing amperage settings. God only knows why Lincoln chose to do it that way. It couldn't have saved them that much money, and it does put the welder at a disadvantage compared to low end welders which do have an increasing duty cycle.

Stan

It makes sense that more amps create more heat so less amps will take longer to get the same heat build up which should result in a higher duty cycle. Is there anything different inside for the 75 setting?

Yes, individual conductors from taps on the transformer to settings on the dial. They start very small at the lowest settings to quite large at the highest. Each size conductor has a different limit to how much current it can carry.

Stan

Does the 75 setting have a bigger conductor than the 90? amp setting?

(quoted from post at 23:28:09 07/13/11) Does the 75 setting have a bigger conductor than the 90? amp setting?

Click to expand...

On the older Lincoln AC-225 the 75 if it is circled is the only 100% duty cycle setting (Some of the newer AC-225 that have a sticker for the number instead of the metal number plate with numbers do not have the 75 circled so it may not be 100% duty cycle on newer ones - I do not know on the newer machines).

Anyway the reason that the 75 is the only one with 100% duty cycle is because that setting is the only setting that is a straight pass through only the primary windings inside the transformer. Every other setting on the Lincoln uses either a dual combination of the primary windings and the secondary windings to attain the amp setting or only the secondary windings for the lower settings. The secondary windings are smaller in wire size hence the reason that every other setting is 20% duty cycle. That said many people have run those old Lincolns with total disregard to duty cycle and never hurt them.

Also, Even though the Lincoln switch is tapped in settings the switch is set-up so that the best combination of the primary and secondarys are automatically always used for the best volt/amp curve for easisest initial arc strikes making it the most error proof system for newbies. In comparison: On a Miller or Hobart buzzbox that utilizes a High and Low range type system you will get the best volt/amp curve in low range as compared to the equivalent setting in High range - this applies to only those setting that are within the overlap section of each range.

The transformer would have to be much larger to increase the duty cycle.I have never seen a welder that had an increased duty as the current output went higher.My Lincoln 225 cost 93 bucks delivered to me in 1964.Was over a weeks pay then.

wow, learning a lot about my buzzbox here. Sounds like the secondary conductors at the different settings are the reason that the duty cycle remains constant, even though the current decreases. Makes sense and I'm wondering if Lincoln did that to make the switch wiring act like a fuse and protect the transformer. Have never heard of anyone burning one up or even having to open one up to repair it or clean contacts or anything.

And 36 Coupe, I do recall looking at a welder when I was just starting to build up my tool collection in the early 70's and thinking that I'd never own one considering I was making $5.85/hr (which was a pretty good paying job at the time.)

(quoted from post at 13:38:37 07/14/11) ... Makes sense and I'm wondering if Lincoln did that to make the switch wiring act like a fuse and protect the transformer. Have never heard of anyone burning one up or even having to open one up to repair it or clean contacts or anything.

Click to expand...

Not exactly - The smaller secondary wires are inside the transformer itself so if you burn them up you have fried the transformer so they do not serve as a fuse at all. Lincoln set the switch up like they did so that the best combination of the primary and secondary coils inside the transformer are automatically used to produce the best volt/amp curve for best initial arc strikes FOR EACH AND EVERY SETTING THAT IS AVAILABLE ON THE WELDER. In other words it is idiot proof.

To better understand: Ask yourself what a welder does? Let's use a Lincoln AC-225 welder as an example since it is the best selling welder of all time. First bit of important information is stick welding is a low voltage, high amp process in order to work best. If welding worked well on high voltage and low amps then we could simply use our household power to weld. Since our house is high voltage then we need to transform that power to something more suitable for welding which is why a welder is needed. In simple terms a welder transforms your household circuit breaker current from your panel(roughly 230 volts and 45 amps input at the full wide open setting) to an output that is suitable for welding which is more along the lines of 79 volts Open circuit (closer to 30 volts when actual welding is occuring) and 225 amps output again at wide open.

A simple transformer is usually made up of a primary coils (big wire) and secondary coils (little wire). In simple terms these coils are simply wire coiled in a circles. The number of turns within the coil affects the end result transformation value.

I do know the 75 amp setting is a straight pass through the primary coil only. ( I do not know how many coils are in the Primary on a Lincoln but lets just guess 75 coils to keep this real easy).

Now lets jump to the 60 amp setting. 2 ways to achieve this setting in theory.
a) Could use 80% of only the primary coils or in other words 60 of our theoretical 75 coils in the Primary only. While the Duty Cyle would still be 100% the volt/amp curve would not be satisfactory or this would be the way to do it.
b) So the better option is to use a portion of Primary's and a portion of the Secondary's that achieve the amp setting needed that also simultaneously produces the best possible volt/amp curve. Unfortunately the downside is that duty cycle is now reduced due to the small wiring in the secondary's. Yes there are alternatives around hurdles like this, but remember this is a pricepoint welder targeted at a homeowner budget. Alternatives that drastically increased duty cycle were much more expensive and affordable only to big business and professional welders at least back in the day.

Ditto for every other setting on the welder!