Hmm.

What you are adjusting with "settings" with any electrical arc welding (the basic settings) is the amount of heat that goes in to the weld. Ultimately this is wattage (the combination of volts AND amps - ohms law).

An 80v open circuit voltage machine at 100 amps, in theory, will have twice the heat in the weld as a 40v open circuit voltage machine - that is, if the voltage under load sags and the same 2:1 ratio is there under load.

That being said -

Usually machines that have "high" and "low" ranges (where you either flip a large switch or physically move leads, usually the latter, between two different ports) are set up that way because they cover a wide range of "weld heat" possibilities. That is usually spelled out as "amperage" on the settings. If you have a switch like a Lincoln AC225, for example, there may be 2 sets of numbers corresponding to the high vs low ranges. Or, if you have something like a Miller Thunderbolt with the infinitely adjustable amperage and the slide indicator has 2 sets of numbers corresponding to a high vs low range - that is usually spelled out as "amperage".

However, the old stick machines were not scientific. What may be "100 amps" on one machine will run a 1/8" 6011 entirely different than another machine on "100 amps". What you need to dial in is what works for YOU on YOUR machine. The number of where you set the machine does not matter - what does is the welding performance at said number and that you can get back to that number. The rods don't care. Your end results do - and if you run 125 amps on your machine and your buddy's inverter stick machine does about the same at 95 amps - who gives a hoot? The ruling indicator is the weld results. If the 95 amps does it - you don't want to run 125 amps on it just because your machine runs at 125 amps. You'll put too much heat in to the weld!

As to the specific question on "voltage" -

The higher the OCV the better the machine will run cellulosic rods like 6010. However, your machine is not DC - so you can not run 6010 (it is DC+ only). The higher the OCV the easier it is to hold an arc, with any rod, but when you get to cellulosic rods it is a big deal. For rods like 6011 and 7018 you can run them fine at 35v or so. There are guys that run "back woods welders" with 2 series car batteries. That is ~24v.

Long story short - the more important metric is how much weld heat you have at what settings. Try the machine out and figure out YOUR settings. Then keep track of them so you can return to them. What YOUR settings are compared to others doesn't matter much - just the results of your welding do.

 

Interesting.... I expected the high low to give the alternate settings like a Forney (low for 80 amps, med for 85, high for 90) but you actually have settings the same on both sides for some heat ranges. Notice that to get 30, 50 or 75 amp settings you have to select low, whereas the 100 to 150 settings are available on either side. I've never used one like that, but unless you are playing with some really thin metal I would just leave it on high since most of my stick welding is more than 1/8" thick. If the chart is still on the bottom of your welder you might want to spend some time studying it.
ATTACH=CONFIG]1738177[/ATTACH]

 

There is in some case to use a low or high setting for some types of rod.

My Hobart was a dial type and did not have high low so I do not know witch rods works best on high or low. You need to find a welder about 30 years older than me.

Dave

 

Miller Thunderbolt as an example gives you two amperage ranges. I don't believe two voltage ranges.

I've never had much luck welding vertical with AC. Maybe with better technique.

Field Res does a series of videos showing the use of voltage choices. We weld with WATTS. WATTS are the product of amps X volts. High volts, low amps can produce the same heat as low volts, high amps.

He explains that vertical weave welds, low volts, high amps penetrates deeper, leaving the molten weld puddle surrounded by frozen steel. You can weld hotter, leaving more deposit with less problem with sag if you reach required watts with low volts.

Conversely, flat weld is less likely to burn through & leaves a flatter bead with high volts & low amps.

 

I doubt the two ranges truly supply two voltage ranges. Open circuit voltage is irrelevant except the moment of first striking an arc. OCV can influence the severity of electric shock a weldor might feel.

Voltage during a weld is indeed important. Many OLD machines, engine drive & motor driven DC generators weld with unusually low voltage. This allows high amperage making vertical & overhead welds a pleasure.

Those with more modern machines can experience this with very short arc length. Jody says: "Turn it high enough it won't stick."

 

Usually...

When there are two terminals on a stick welder you generally use the one with the higher output current capability - this has the lower OCV (open circuit voltage). Some rods (electrodes) require a higher OCV and for those you use the other terminal but there is not quite as much current available.

The terminals are not consistently named - sometimes "High" means high current, sometimes it means high voltage.

In essence, it is a kludge to get obstinate rods to fire.

Jack

 

when should I choose low voltage?

Thanks!

only on the days you feel scared.

when should I choose high voltage

Thanks!

Always.

 

On my old CRAFTSMAN machine the high range is 0 to 230 amps, low range stops at about 130 amps IIRC, the owners/operators manual stated that low range would give a more stable arc, and I found that to be true.

 

On that welder high amps receptacle has a lower open circuit voltage than the Low receptacle. The low receptacle will only weld 7018AC rod, you won't be able to get an arc started with 7018 DC rod. 6011 doesn't care. Can't explain it. but all these welders of this type miller , airco are all the same.

 

Don't know the vintage of your welder, but here is from the 1987 version of the Miller Thunderbolt 225. This is what you get on low/hi ranges.

View attachment miller thunderbolt 225 1987 V-A curve.JPG

Here's what it looks like inside, schematically:

View attachment miller thunderbolt 225 schematic 1987.JPG

 

Oldendum has it right. A lot of welders like this have two ranges because of different transformer taps. I would always use low range (which should have the higher open circuit voltage, up to a point) whenever possible. Are you sure the measurements on yours aren't backwards?

 

Your right. I wrote it backwards. I'm sorry. It's the low tap that has higher voltage and the high tap that has lower voltage.

 

Judging from the Volt-Amp curves Oldendum posted, I would use the High range (the "B" curve that's closer to horizontal) for 6011 (to give more dig) and the Low range (the "A" curve closer to vertical) for 7018, because the "A" V-A curve should be more forgiving of changes in arc length.

If you look at the two curves, you can see that as you change arc length (and thus arc voltage -- the vertical scale), the "A" (low range) curve changes the amperage less than the "B" curve. What that should mean when you use the welder is that on the "B" (high range) curve, as you decrease the arc length (and arc voltage), the amperage will increase more than it would on the "A" curve, giving you more dig.

By the same token, changing the arc length when using the "A" tap will change the amperage less than when on the 'B" tap, meaning your amperage should stay more constant with changes in arc length, giving less dig (and less chance of blow-through) than when on the "B" tap.

The OCV on the "B" or "High Range" curve should be lower than on the "A" curve (looks like it should be about 55V on B versus 75V on A), meaning it'll be more prone to sticking on startup, but that's just the way the mop flops...my engine drive welder behaves the same way.

This might help:

As you can see, decreasing the arc-voltage from 35V to 25V (by shortening arc length) increases the amperage by a far larger percentage on curve "D" than it does on curve "A" because the curve is closer to horizontal on "D" than on "A" (or mathematically, you would say the curve has "less slope" on "D" than on "A")... same deal with the V-A curves Oldencum posted...

 

I think I got to read this again. Ha. I always thought it was just me didnt get a grip sometimes. On to other items.

I've never had much luck welding vertical with AC. Maybe with better technique.

This is 7018AC. I think I might have burned it as a demo rod maybe, cant member but,,,,, as I recall they mi9ght even include it in instruction sheet somewhere in a time and place far away that you got to weave it to get it toi hang in and its a pretty disciplined deal. This is about as good as I do without any practice.
I dont have AC 11 pics and I did a lot of it 40 years ago but I am sure its led to a lot of downhill and same for 13 on AC. With some practice could flat that some more but DC makes it a lot easier.

 

Hey Bud, that Tbolt is pretty. To the OP. That machine is nice in its own way, its better than no welder, I have used them a lot when its what I /we had and in fact often got some work due to the proficiency with one but,,, given modern economics and vast improvement of DC its obsolete. That doesnt mean it cant be used and if you do, get some AC 7018 and you can thank me later. For Home hobby its one of the 3/32 electrodes that work well, everything else I like in 1/8 if I run out of the other. Get it hot enuf and go slow enough and its hard to miss.
Do yourself another favor, put wheels on it and use as a cart for a Tbolt like or a dvi if I was gonna buy new,,, and on top of that if I was really serious that 180 Esab a couple guys here like. Could ditch all that 11 stuff.
I am kind of old school in what I use, I already own it but the start features would interest me if I had to get a new machine.
The weld above looks like it was on a dirty plate, makes it all the harder to get wet along the edges and throws off the weave timing. Might be better in a light pass also, kind of looks like big ole fatty 1 pass job.

 

If I was welding regular would snap up some pics with variations of this, sometimes a little rod makes for nice finish and sometimes bigger rod faster can be better uphill to get bit bigger bead.

 

I just remembered why you would use high or low.
Using low hydrogen on small welds use the low side in gives a little higher OCV and the rod will star easier.

That is from the 1960's and machine I used was a dial type and had high OCV .

Dave

 

Judging from the Volt-Amp curves Oldendum posted, I would use the High range (the "B" curve that's closer to horizontal) for 6011 (to give more dig) and the Low range (the "A" curve closer to vertical) for 7018, because the "A" V-A curve should be more forgiving of changes in arc length.

Sure you dont got the rods confused? Another thing in regards to 11,,,, just cause a guy CAN make it dig more doesnt mean he wants it to.

 

Agreed. But if I did want more dig (typically with 6010 or 6011 for a deep root), I would use the tap mentioned.

I have no idea what you mean about getting the rods confused. On my engine drive welder, I use low gear high range to give a more buttery arc with 7018, and when I want more dig for 6010, I use high gear (which has lower OCV, unfortunately) and low range on the "fine" adjustment. I've never heard of doing it any other way. If I don't care about dig with 6010, I might use a lower range gear, but rarely, probably because I'm just accustomed to running 6010 on the high tap and low fine adjustment.

My overall points, since you seem to have missed them, were that:
1. Tap "B" in Oldendum's V-A curves will give more dig and more variation in amperage with changes in arc length (and lower OCV), while
2. Tap "A" in Oldendum's V-A curves will give less dig, but more consistency in amperage with changes in arc length (and higher OCV).

My other points were just follow-on points.
If I want more dig, it's generally gonna be with 6010/6011.
And if I want a more consistent amperage, it's generally gonna be with 7018.
Capice?

 

Arc length varies a lot on 11. I dont use it due to dig so much as fast freeze. There seems to be a lot of impression every 10 or 11 gets covered, yes, some do but in gewneral work most;ly making a weld regardless of the rod, single pass stuff if it can be done.

 

Could melt a hole inm this with 18 too but it cools too slow to stack it up.

 

I read the stuff back and forth and u guys lost me again. Those are both 1/4 plate I believe. number 1 is no bevel butt and 2 is a T. The cooling stroke where its being stacked is not really 90 degree, closer to 45. This pic is the back of the vert above and 2nd is a bit more organized with it turned down a pinch, the others mainly to show how hot, how to melt, how to get it to hang in there. Pic 1 in both posts the same joint, note how got too much out the back and not quite flush on the front.
I guess what I was getting at is not much variation with arc length to 18 but lots to 10 and 11,,, why some inverters wont run them. You can change current a little but really use the length to get out of the way while the last spot cools.
If some of those are off to one side I had my hands full giving instruction.

 

I guess what I was getting at is not much variation with arc length to 18 but lots to 10 and 11,,, why some inverters wont run them. You can change current a little but really use the length to get out of the way while the last spot cools.
If some of those are off to one side I had my hands full giving instruction.

Well, remember that the other side of the coin is also true.

A tap that increases the current more when arc voltage (and arc length) decreases (giving you more dig) is ALSO going to DROP the current by a greater percentage when arc voltage increases (when you long arc to let the puddle cool).

Just look at the V-A curves. It's self-explanatory.

 

As mentioned in the other thread , here's the manual the thunderbolt 225AC :



View attachment thunderbolt225accover.jpg




View attachment thunderbolt225acadjduty.jpg



These were the only things I could find online for the Airco. :



View attachment aircomanualpic2.jpg


View attachment aircomanualpic.jpg

 

Just look at the V-A curves. It's self-explanatory.

If I could really read those I would have been an engineer and maybe slave away under a hot secretary somewhere.

 

Just throwing this in to add to the confusion. :laugh: This is the best 50 cent book I ever bought, though it's falling apart. Lincoln Procedure Handbook ...

View attachment Lincoln VA curve arc force 1.jpg

View attachment Lincoln VA curve arc force 2.jpg

 

The curve looks like a resistor type.
The voltage is higher for high amperage.

Dave

Just throwing this in to add to the confusion. :laugh: This is the best 50 cent book I ever bought, though it's falling apart. Lincoln Procedure Handbook ...

View attachment 1738328

View attachment 1738329

 

If you have open circuit voltages like that, something is wrong. The LOW (current tap) should have much higher open circuit voltage, like ~ 70 - 80V.

 

Oops -- misunderstood Oldendum's post and replied erroneously -- sorry Bob! (Where's that delete button?)

I wonder whether some AC-only welders have especially low OCV to reduce the risk of getting zapped? I've heard AC is more dangerous than DC due to the risk of heart fibrillation...

 

I believe they do. The Maxstar has low ocv safety feature just for that. I realize its DC but they do. Very hi on AC certainly has the potential to be fatel especially in wet work, sitting on steel etc.

 

Offhand........I usually run my little Ranger at the next range up because I don't like the soft arc in the lower ranges. There's a pretty healthy overlap on the ranges, so you can run 1/8 7018 in the range that goes to 180amps. Likewise, I'll run 3/32 7018 in the 130amp range. Did that since the machine was new. Maybe just a Sam thing:laugh: