stabilizing the DC output of a cheap mig welder?

I bought one of those cheap chinese mig welders, It splatters alot and
is alittle unstable. I
removed the case to find only a transformer and two diodes. Im
thinking of adding a inductor
in the + dc line, most good dc welders have atleast this. Is there any
other improvements
i could do to stabilize the output? Would filter caps help?

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