0.6 wire burn back?

[Richard B]

I have a NuTool 255N Mig, I always used to use 0.6mm, but now it keeps arcing back to the tip.

Wire speed 5
Power 3 (out of 8, or is that 16?)
Weldpool CO2

I'm having to use 0.8mm wire instead, which is a bit heavy for car bodywork. Has the wire supplied got softer over the years, am I doing something wrong or has a fault developed in the Mig? I know that the steel supplied is softer as you cannot get Automotive Steel "like wot you used to get".

There are two Earth points one the unit, am I correct in assuming that one is 1/2 the power of the other? The Torch plugs into a thrid socket for reversing the polarity. I had a problem previously where the tube that takes the wire to the torch had worn and kept sticking.

Richard welding up old Triumph cars.

 

[bigbadbugga]

I think 2 earths is usually for gas/no gas polarity change, I might be wrong though.

Have you tried turning up the wire feed a little to stop the burn back?

also, when you are about to stop welding pull the torch slightly back from the work to allow a little more wire out before you let go of the trigger.

 

[shenion]

Usually 2 earths are for low an high inductance. Any symbols/markings on the terminals?

 

[Richard B]

Nutool NU255N

I probably did not make myself clear,

I have three sockets;

1 x Live feed (torch)
2 x Earth sockets

Presumably the live feed can switch with the earth to change the polarity but there are two earth sockets.

I thought this gave a full power and a half power setting?

 

[shenion]

Again, are there any markings on the two earth terminals?

I doubt it would be high/low power. More likely inductance settings.

 

[wyn]

As shenion says they are likely to be for inductance.


Do they look anything like on the bottom of this welder (not very clear)







Better pic