I’ve had my Mig 135 since June. I’ve run two spools of 0.30 Lincoln wire with gas through it with no problem, working with new 18 guage sheet metal making nice welds. Now all of a sudden I’m getting cold welds with no penetration where before I had to be very careful about blow through. The wire just turns cherry red and piles up. I backed off the wire speed and cranked up the volts all the way and this helped some but then it blows through the duty cycle in nothing flat, which it never used to do. I have used my grinder to buff the area where I attach the grounding clamp so its got a nice contact with the material. Moved the grounding clamp closer to the work with no effect. Grounding clamp shows no heat after use/ cool to the touch. Changed to a new wire spool. Changed tips. Using the same gas bottle as when it was making nice welds. Anyone have any ideas what happened?