complete newbie - any advice on what I am doing, both right and (mainly) wrong

[martynhills]

Hi here are some pics of some welds I have done. It's my third attempt. I have a sealey 130xt with argon (2% co2). Any advice would be great. The welder has no wire speed or voltage setting help that I can find and no info on required gas pressure. So complete guess work - thanks Martyn

 

[Richard.]

Co2 level is a touch low for steel that's the sort of mix commonly used for ss. You need a higher percentage of active gas 5-25% in the mixed gas to gain better penetration, wetting, weld toe transition.

 

[martynhills]

Thanks for your post Richard, I double checked the gas and it is BOC argoshield light. 5% co2, 2%o2 and 93% argon. Is that ok?

 

[Richard.]

Yes that's a lot more suitable. Beads look cold and excessive with hight. Get some voltage put on them to spread the weld metal out .

 

[martynhills]

Thanks I'll give that a blast. I tried lowering the voltage and speeding the wire feed as when I got to the end (last pic) the bar was glowing with heat, assuming that I was doing the reverse

Martyn

 

[Richard.]

I'm not much of a mig welder tbh as it's the process I've had least to do with in my career but understanding what your 3 settings do will help you perfect your runs.
Wire speed gives you penetration depth
Voltage gives your bead spread
Travel speed determines your bead reinforcement.(material deposit on top)

 

[v8burbling]

I'm not that experienced either but I thought it was the ratio of wire speed to voltage that was important, i.e. you can use a higher wire speed with a higher voltage or vice versa. It is the heat of the weld that I thought gave the penetration. Increasing your voltage or slowing the wire speed for the same voltage setting will increase the heat of the weld. Travel speed governs how much wire you put down at any particular point, so moving fast gives a thinner bead.
Hopefully a knowledgable person will come along soon to give us the right answer lol !

 

[Spark plug]

I'm not that experienced either but I thought it was the ratio of wire speed to voltage that was important, i.e. you can use a higher wire speed with a higher voltage or vice versa. It is the heat of the weld that I thought gave the penetration. Increasing your voltage or slowing the wire speed for the same voltage setting will increase the heat of the weld. Travel speed governs how much wire you put down at any particular point, so moving fast gives a thinner bead.
Hopefully a knowledgable person will come along soon to give us the right answer lol !

Your sort of right but as the wire speed increaces so dose the Amps, this is the link between wire speed and penetration. So if you need more penetration up the voltage and the wire speed, and adjust you travel speed to control your bead width.

 

[Richard.]

I'm afraid although im not the most gifted with a mig torch I have got it right with regard to what setting governs what outcome. If you have a certain wfs set and you decrease the voltage (to a point) you will actually increase penetration. Add a few volts to that wfs and you will decrease penetration. Voltage adds spread to the weld bead and the more you spread it with higher volts the less it penetrates down. Spark plug has it right in the respect that amperage is the penetration factor which is generated by wfs and stickout only. Voltage and travel speed bear little or no effect on penetration. You still need volts to weld or you won't melt the consumable so without them you won't penetrate at all which is why I said to a point.

 

[v8burbling]

Now I'm very confused. I have switches on the front of my welder that are 1,2,3 and MIN/MAX. I understood that increasing 1MIN, 1MAX, 2MIN, 2MAX etc was increasing the voltage and therefore the current (if you increase voltage for the same circuit resistance, you increase the current as V=IxR from Ohm's law).
Are you saying that the wire speed control on my welder also increases the current ?

I would have thought that any increase in voltage and or current would cause increased heat (as Heat=I squared xR) and if it's hotter, the weld will penetrate deeper.

 

[Spark plug]

Now I'm very confused. I have switches on the front of my welder that are 1,2,3 and MIN/MAX. I understood that increasing 1MIN, 1MAX, 2MIN, 2MAX etc was increasing the voltage and therefore the current (if you increase voltage for the same circuit resistance, you increase the current as V=IxR from Ohm's law).
Are you saying that the wire speed control on my welder also increases the current ?

I would have thought that any increase in voltage and or current would cause increased heat (as Heat=I squared xR) and if it's hotter, the weld will penetrate deeper.

This is exactly what I thort when I started welding, had to learn the hard way when welds wouldn't do what I wanted. Yes wire speed and current are related in effect the wire speed changes the resistance of the circuit.

 

[v8burbling]

Just checked my welder handbook and the switches on the front definitely set voltage. The book recommends low wire speeds with low voltage settings (e.g. 1MIN and 1MAX) and high wire speeds with high voltage settings (eg 3MIN and 3MAX).

Looking at teh electrical diagram at the back of my welder handbook, the wire feed setting appears to have no bearing on the welder power circuit only the feed to the drive motor.

 

[v8burbling]

Here's an interesting link I found:
http://www.esabna.com/euweb/mig_handbook/592mig7_7.htm
Gives some good explanations.

It has explained the stick out thing to me now. The ref talks about 'tip-to-work' distance which makes more sense. It makes sense that as this distance increases, the resistance increases so the welding current for a given voltage would go down and therefore probably penetration too.

We could both be right on the volts/amps thing too Sparkplug. Increasing volts must increase current to my understanding. However, the above reference shows three examples of penetration agains different voltages and there seems to be an optimum voltage setting for penetration where increasing or decreasing voltage either side causes reduced penetration. So it would be possible for penetration to increase if you reduced voltage as you said Sparkplug but that isn't because the current has reduced (which was what was confusing me), it's due to other factors like unstable arc. So it seems that there isn't a direct link between current and penetration.

It's much more technical than I thought this welding malarky !

 

[Spark plug]

Yes as you say technique has a lot to do with it, I've learned how to do it but it's hard to explain.

I started with a 185a mig with 6 voltage settings I got good results but didn't learn why

It wasn't till I upgraded to a 380a machine with 40 voltage settings that I started to understand the process from a more technical point of view.

What size wire are you useing? If your useing 0.6mm this could be ware your struggling, I found it was only any good for rusty old cars not producing good welds.

Wire diameter is linked to current as well as a given wire diameter can only carry a limited amount of current regardless of voltage

 

[v8burbling]

I am using 0.6mm yes. Understood this was best for learners and the steel thickness I am using, i.e. 2mm and 1.2mm.

 

[Richard.]

Here's an interesting link I found:
http://www.esabna.com/euweb/mig_handbook/592mig7_7.htm
Gives some good explanations.

It has explained the stick out thing to me now. The ref talks about 'tip-to-work' distance which makes more sense. It makes sense that as this distance increases, the resistance increases so the welding current for a given voltage would go down and therefore probably penetration too.

We could both be right on the volts/amps thing too Sparkplug. Increasing volts must increase current to my understanding. However, the above reference shows three examples of penetration agains different voltages and there seems to be an optimum voltage setting for penetration where increasing or decreasing voltage either side causes reduced penetration. So it would be possible for penetration to increase if you reduced voltage as you said Sparkplug but that isn't because the current has reduced (which was what was confusing me), it's due to other factors like unstable arc. So it seems that there isn't a direct link between current and penetration.

It's much more technical than I thought this welding malarky !

I think your looking at it in an electrical therory which is where confusion sets in. Think of it from a mechanical point of view.
Voltage is heat which melts your consumable. Wire feed is the rate your forcing the consumable into the joint. By adding more heat your melting it further making it more fluent there for it spreads wider not deeper. Add more WFS and your forcing the consumable deeper into the joint thus increasing penetration.

 

[v8burbling]

I think your looking at it in an electrical therory which is where confusion sets in. Think of it from a mechanical point of view.
Voltage is heat which melts your consumable. Wire feed is the rate your forcing the consumable into the joint. By adding more heat your melting it further making it more fluent there for it spreads wider not deeper. Add more WFS and your forcing the consumable deeper into the joint thus increasing penetration.

You might be right. I'm an electrical engineer so that's inevitable I'm afraid lol! It's current that generates heat but voltage drives current so they are directly linked. For example, batteries hold a voltage but they don't cause any heat . If you add more batteries together they don't get hot. However, if you short their terminals with a wire and let a lot of current flow through the battery, it gets very hot.

Good explanation on the heating and spreading - hadn't thought of that....makes sense. I had wondered if a higher wire speed would force it deeper into the joint but I guess it can only do that if there is enough heat to melt the parent metal ?

Can be very frustrating welding. It's a bit like golf (when I used to try to play that). You can get great results when practicing, then you try on the real thing and it all goes to pot !

 

[Richard.]

I'm not electrical. I'm day in day out directly in the welding game more from a technical point rather than production.
WFS and stickout are are directly linked with current which effects penetration. Voltage may have an effect on current but it's main effect in welding is it widens the arc and spreads the bead. It does not increase penetration. Like I said before if anything by turning up the voltage and leaving the WFS where it is you can actually de crease penetration because your feeding the same amount of metal in but your spreading it wider with a wider arc.

 

[Kent]

You can seriously overthink MIG welding. Try and forget the technical detail and go off what you see and hear. The right setting is the one that gets the desired result, wire feed and power settings should just balance each other. The weld does look cold so up the power keep feeding wire into the hottest spot (front of puddle) and go experiment on settings on more scrap. When your happy write it down and K.I.S.S
Oh very important to have a good ground connection so make it as good as it can be then try and improve things

 

[v8burbling]

Oh very important to have a good ground connection so make it as good as it can be then try and improve things

Changed my ground clamp for a much better one. One question on this is when you are doing a butt joint, do you put the clamp on the old metal or then new or do you bridge the two ? I was using magnets to hold the two pieces together and had the ground clamp on the larger peice to do the spot welds. I noticed sparks flying around the magnets when spot welding and burn marks under them when removed. It seemed that the welder current used the magnets to get from one piece of metal to the other. Perhaps I should be using welding clamps as well as the magnets ?