Getting too much build - wire speed or something else

[v8burbling]

Hi there,
Welding 2mm steel on a chassis repair and finding that I tend to get too much weld height and need to do lots of grinding down. It also worries me that this could also indicate lack of penetration.

I first tried lowering the wire speed but that causes the usual nice welding crackle to change to a buzz and spluttering as the wire appears to burn through before it reaches the metal. So I increase the wire speed again to bring it back.

Could it be because I am holding the gun too far away from the job ?

 

[Wozzaaah]

What welder and what power setting?

 

[nickk]

you could be moving/travelling too slowly.

 

[Chris Stevens]

Sounds like you are using .6mm wire? Will be easier with .8mm............

 

[WorkshopChris]

As Wozzaaah said what settings do you have? if you are not sure about penetration can you go up a power setting or is the machine maxed out?

Sounds like you are using .6mm wire? Will be easier with .8mm............

Just out of intrest chris what info in the above let you guess at the wire diameter, as they say every day is a school day.

 

[Chris Stevens]

I did vehicle welding professionally for 5 years, always used .8mm wire. One day I ran out and could only get .6mm, found it was ok for thin sheet, but nowhere near as good as .8mm for heavier chassis repairs.............took it off and changed back to .8mm as soon as I could.

But as OP has asked question without providing any details at all as to what set up he has, the point about wire size is only my own personal experience, which may or may not be relevant in this case..............

 

[Kent]

Your putting too much filler in basically, including be because of
Travel speed
Wire speed
Lack of power / penetration
Poor return contact
Poor angle of dangle ( technique)

Take your pick can't really deduce more

 

[WorkshopChris]

Another thing that will affect the weld, are you running Co2 or a argon mix both will have different effects on weld profile.

 

[v8burbling]

What welder and what power setting?

Sorry, it's a Clarke MIG 150A and I am using power setting 2 on MAX (it goes 1-3 with MIN/MAX) and wire feed speed 6.5

Have tried higher settings but the wire speed had to be increased to prevent the above happening, which made things worse.

 

[v8burbling]

Sounds like you are using .6mm wire? Will be easier with .8mm............

Correct. Ah, you are saying that the 0.8 can hold the higher current at slower wire feeds as it is thicker ?

 

[v8burbling]

Another thing that will affect the weld, are you running Co2 or a argon mix both will have different effects on weld profile.

Using BOC Argoshield with a proper BOC regulator, after advice from these forums - best thing I ever did for my welding!

 

[WorkshopChris]

This might be totally irrelevant if so apologies to everyone, my memory is terrible at the moment.

There was a post about settings on one of the smaller migs and they were all opposite from what you would expect.
But can remember title or what range it applied to.

 

[Chris Stevens]

Correct. Ah, you are saying that the 0.8 can hold the higher current at slower wire feeds as it is thicker ?

I would suggest you get some .8mm..............with any luck that might help quite a lot. Before changing wire though, try welding some 2mm on the bench, and see if you can then get a full pen weld. When I did car welding, always found it a bit more fiddly to do positional on chassis, than downhand on floor pans etc.

 

[WorkshopChris]

See if you can get hold of some lincoln ULTRA-MAG should be available in 5 Kg, the difference over a generic white box or own brand wire can be significant.

 

[v8burbling]

I would suggest you get some .8mm..............with any luck that might help quite a lot. Before changing wire though, try welding some 2mm on the bench, and see if you can then get a full pen weld. When I did car welding, always found it a bit more fiddly to do positional on chassis, than downhand on floor pans etc.

Thanks Chris,
Excuse ignorance but what is a full pen weld ?
My main concern is that I did some 2mm butt welding on the bench and the weld wasn't visible on the other side. You could still see the edges of both sheets of metal. I tried breaking down the joint by hammering it over the corner of the bench back and forth at the join and I couldn't break it, so not weak but probably weaker than it could be if you know what I mean.

 

[Chris Stevens]

Thanks Chris,
Excuse ignorance but what is a full pen weld ?
My main concern is that I did some 2mm butt welding on the bench and the weld wasn't visible on the other side. You could still see the edges of both sheets of metal. I tried breaking down the joint by hammering it over the corner of the bench back and forth at the join and I couldn't break it, so not weak but probably weaker than it could be if you know what I mean.

Full penetration weld.............relatively important for chassis work. I would guess to get full pen with something like a 150A Clarke, that trying .8mm at full power might work fine..............its simply a matter of trying it and seeing what happens. Also carefully check earth cable as poor connections here can make machine seem like it has less power. You also might try slowing down travel speed a bit.

 

[v8burbling]

Full penetration weld.............relatively important for chassis work. I would guess to get full pen with something like a 150A Clarke, that trying .8mm at full power might work fine..............its simply a matter of trying it and seeing what happens. Also carefully check earth cable as poor connections here can make machine seem like it has less power. You also might try slowing down travel speed a bit.

Thanks Chris,
I'll try the 0.8. If that allows me to use the higher power settings without having to increase the wire speed to prevent it burning out, that may well increase penetration. If I could slow down the travel speed too that would be great as I am having to move pretty quickly at the moment and finding it difficult to keep steady at that rate.

 

[Chris Stevens]

.8mm might help hopefully, but before trying it, feel the earth cable after welding at high amps, and see if its warming up. If its getting hot, might have some issues with the earth clamp

 

[v8burbling]

.8mm might help hopefully, but before trying it, feel the earth cable after welding at high amps, and see if its warming up. If its getting hot, might have some issues with the earth clamp

Thanks. I have replaced the clamp that came with the welder with a better quality one and ensured a good connection with the cable. I have noticed that if I weld close to the clamp, the old metal is more likely to burn through than when I am further away up the chassis (say 1metre away). I guess that's just resistance between the job and the clamp position.

 

[Chris Stevens]

Distance from earth shouldnt make a great deal of difference. Is earth cable heating up when welding at all?