- Thread starter rn4x4
- Start date
Welcome to the forum!
Distortion is caused by too much heat building up too quickly in a given area, so it depends more on how you are trying to weld thin car panels than whether you are using gasless flux-cored wire or gas wire. Gasless is more likely to blow through thin metal before it distorts anything, unless you are doing very short tacks.
1. If you are welding in short tacks, and either pausing between tacks, or widely spacing them, you are less likely to get distortion, using gas or gasless.
2. If you do a row of tacks one on another almost without pausing, there is more chance of distortion, depending on thickness of metal, because the heat is building up as you go along. Heat will build up more quickly with gasless wire, all things being equal, and you will be likely to blow through.
3. If you try to weld a longish bead on thin stuff you will certainly be likely to get distortion, if you don't blow through first.
These are generalisations, and skill and experience in technique can mean some people and some machines can weld beads on very thin metal without any noticeable distortion. A pro machine with a properly set stitch weld facility, for example, can run a pulsed bead without excessive heating, because the heat input is being switched on and off very very quickly.
Distortion is caused by too much heat building up too quickly in a given area, so it depends more on how you are trying to weld thin car panels than whether you are using gasless flux-cored wire or gas wire. Gasless is more likely to blow through thin metal before it distorts anything, unless you are doing very short tacks.
1. If you are welding in short tacks, and either pausing between tacks, or widely spacing them, you are less likely to get distortion, using gas or gasless.
2. If you do a row of tacks one on another almost without pausing, there is more chance of distortion, depending on thickness of metal, because the heat is building up as you go along. Heat will build up more quickly with gasless wire, all things being equal, and you will be likely to blow through.
3. If you try to weld a longish bead on thin stuff you will certainly be likely to get distortion, if you don't blow through first.
These are generalisations, and skill and experience in technique can mean some people and some machines can weld beads on very thin metal without any noticeable distortion. A pro machine with a properly set stitch weld facility, for example, can run a pulsed bead without excessive heating, because the heat input is being switched on and off very very quickly.
Hi Keith,
Firstly, thank you for both the welcome and answering my question.
Have used oxy and arc welders over the past 30 years but about to try a mig welder for the first time.
So putting aside both the operator and welding machine.....there is no advantage of using gas over gasless when it
comes to putting unwanted heat into a panel? But what you are saying is that using gas reduces the likelyhood of blow through!
Little confused with that...as isn't the blow through caused by too much heat? So using gas, should in theory be putting less heat into the panel. Or is it that the extra heat from gasless even though more likely to cause blow through.... is insignificant to cause any distortion?
So basically speaking is the only advantage if I use gas, cleaner welds with less chance of blow through!
cheers
Robert
Firstly, thank you for both the welcome and answering my question.
Have used oxy and arc welders over the past 30 years but about to try a mig welder for the first time.
So putting aside both the operator and welding machine.....there is no advantage of using gas over gasless when it
comes to putting unwanted heat into a panel? But what you are saying is that using gas reduces the likelyhood of blow through!
Little confused with that...as isn't the blow through caused by too much heat? So using gas, should in theory be putting less heat into the panel. Or is it that the extra heat from gasless even though more likely to cause blow through.... is insignificant to cause any distortion?
So basically speaking is the only advantage if I use gas, cleaner welds with less chance of blow through!
cheers
Robert
fuff66uk
Member
- Messages
- 381
I have been told that Lincoln Electric Innershield NR-211-MP helps a bit when using gasless on body panels,don't know yet as i haven't started my car
http://www.rapidwelding.com/dynamic/DisplayItem.aspx?c=ED031448
I am not connected with rapid welding just passing on the link that was sent to me
http://www.rapidwelding.com/dynamic/DisplayItem.aspx?c=ED031448
I am not connected with rapid welding just passing on the link that was sent to me
Country Joe
Argoshield Dark
- Messages
- 1,743
- Location
- Somerset - United Kingdom
The bit (on that link) that says:-
"It is recommended for maximum plate thicknesses in the range of 7.9 mm to 12.7 mm", would put me off!
Having said that, I have used it before now, and it seemed quite a bit better than some other gas-less wires.
All the Best,
CJ
P.S. Rapid welding is where mine came from.
"It is recommended for maximum plate thicknesses in the range of 7.9 mm to 12.7 mm", would put me off!
Having said that, I have used it before now, and it seemed quite a bit better than some other gas-less wires.
All the Best,
CJ
P.S. Rapid welding is where mine came from.
Hi Robert,
Sorry if I didn't explain more fully. I tend to write in a bit of a rush. Glad to hear you aren't by any means a novice to welding though. I used to do stick welding, and now I quite like gasless mig welding, because there are some similarities. Using gasless wire on thin metal is a bit like running a high-quality 1.6 mm rod on 1.2 mm steel. Not by any means impossible, but difficult to run a bead for long without blowing through. But with mig you have the ability to constantly tack, which is more difficult with an arc welder.
Blow through and distortion are two quite different effects of excess heat.
Blow through only occurs in a very small, localised area, usually along the line of weld, as you'll know if you have done arc welding on thinnish metal. Short-term heat buildup collapses the structure of the metal at the point of the arc or the small area kept under the heat of the flame in oxy gas welding.
Distortion can occur over a wide area as a result of too much heat overall being put into only part of that area. For example, when oxy gas welding a patch into a thin but large vehicle panel, we have to be very careful of excess heat build up around the edges of the patch, otherwise when it cools and shrinks it pulls the rest of the panel out of shape slightly, causing unsightly distortion.
So with mig flux-cored wire we get more heat, more quickly, and as a result we are more likely to get blow through directly along the line of weld. If we tack, space, tack, space, etc, there is less likelihood of blowing through, and because there is less heat in the weld area, less chance of distortion in the rest of the panel.
The same goes for mig gas wire welding, except that this is a bit cooler, so we can, with experience, tack a bit faster, or closer together, or make longer tacks. Argon/CO2 mix gas gives a cooler weld than CO2 alone, and both are cooler than flux-cored gasless.
But if we run a bead on thin metal - we are talking 0.6mm - 1mm here - heat can build up along the line of weld, so even with gas wire we run both the risk of blow through and distortion on very thin panels, and the general advice is to proceed carefully. Take a look at:http://www.mig-welding.co.uk/thin-metal.htm
Sorry if I didn't explain more fully. I tend to write in a bit of a rush. Glad to hear you aren't by any means a novice to welding though. I used to do stick welding, and now I quite like gasless mig welding, because there are some similarities. Using gasless wire on thin metal is a bit like running a high-quality 1.6 mm rod on 1.2 mm steel. Not by any means impossible, but difficult to run a bead for long without blowing through. But with mig you have the ability to constantly tack, which is more difficult with an arc welder.
Blow through and distortion are two quite different effects of excess heat.
Blow through only occurs in a very small, localised area, usually along the line of weld, as you'll know if you have done arc welding on thinnish metal. Short-term heat buildup collapses the structure of the metal at the point of the arc or the small area kept under the heat of the flame in oxy gas welding.
Distortion can occur over a wide area as a result of too much heat overall being put into only part of that area. For example, when oxy gas welding a patch into a thin but large vehicle panel, we have to be very careful of excess heat build up around the edges of the patch, otherwise when it cools and shrinks it pulls the rest of the panel out of shape slightly, causing unsightly distortion.
So with mig flux-cored wire we get more heat, more quickly, and as a result we are more likely to get blow through directly along the line of weld. If we tack, space, tack, space, etc, there is less likelihood of blowing through, and because there is less heat in the weld area, less chance of distortion in the rest of the panel.
The same goes for mig gas wire welding, except that this is a bit cooler, so we can, with experience, tack a bit faster, or closer together, or make longer tacks. Argon/CO2 mix gas gives a cooler weld than CO2 alone, and both are cooler than flux-cored gasless.
But if we run a bead on thin metal - we are talking 0.6mm - 1mm here - heat can build up along the line of weld, so even with gas wire we run both the risk of blow through and distortion on very thin panels, and the general advice is to proceed carefully. Take a look at:http://www.mig-welding.co.uk/thin-metal.htm
