Weld pulsing causing splatter

[james99h]

Hi Everybody
I'm new to the forum so firstly hello all. I am looking for help with a problem my mig has developed,I own a fabricator 180 mig for a few years and recently has a fault where the weld seems to pulse at high frequency causing bad welds, splattering, and poor penetration, I'm wondering if the capacitor or choke is U/S. Has anybody seen this fault before?

 

[Lawnmowerboy]

Does it have a pulse mode that is accidentally been switched on by any chance?

 

[james99h]

Hi thanks for replying
there is no pulse mode on this welder.

 

[gavuk]

Is that the thermal arc mig?,mine sparks if the wire is touched to work-piece,even without pulling the trigger,I've always assumed this is the capacitor discharging?

 

[mike 109444]

James could it be that the wire feed is juddering and causing what appears as pulsing at the weld? Try and have your tourch lead as streight as possible and try some test runs to see if it makes any difference, might be you need a new liner and or tip. Does the fault happen accross all the power settings? Might be you have a failing diode in the diode pack thats allowing some ac through (bit unlikely I would have thought).

 

[james99h]

Thanks for replies... I cannot see any juddering in the wire feed at all, i disconnected the capacitor, which made it a lot worse, so it appears its OK.
I still wonder if the choke is U/S as there seems to be a lot of the insulating vanish oozing out of the coils and solidified. I have a 250A rectifier somewhere
so may try replacing it.

 

[mike 109444]

james think you will find that's how the coil is made. They dip the coil in special varnish and allow it to drip dry causing the oozing and rough look. It's not easy to meter the coil as it will show as a dead short even with a low setting meter. You could make one up as someone on here has done by winding enamel wire round a piece of iron pipe (old drain pipe?).