MIG - problems on startup

Greets all.. I've got a 3ph 300A Italian-made Weldtronic mig welder.
Have had it a few years now, gone through 2 or 3 replacement guns,
without any problems. Lately, however, its been acting strange: poor
starting.. 2 out of 5 times when i start a bead the wire "blows" and
melts back into the nozzle. been losing more time fishing the thing
back out.. usually shaking the gun around (i try to not bang it) breaks
the wire free and i'm good to go again.
first 1/4" or so of weldbead is *always* cold. real ugly looking and
lots of spatter. my work-around has been to fire the gun on my
weldingtable.. like a little spot weld.. and then pick up on my work.
this way it welds just fine -- but now i spend my last 1/2hr of the day
grinding down all the spotweld bumps on my welding table.
anyone have any idea what might be causing this? i have changed to a
new gun recently (not an OEM gun) but i'm not sure if this is when the
problems started.. plus.. what difference could the gun make?
I have a "stick out" trimpot on the front of the machine that goes
through 3/4 of a turn with a small screwdriver. have no idea what its
really for, but messing with it doesnt seem to change the symptoms.
thanks,
-tony
Reply to
outofstepper
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"outofstepper" (clip) my work-around has been to fire the gun on my weldingtable.. like a little spot weld.. and then pick up on my work. this way it welds just fine -- but now i spend my last 1/2hr of the day grinding down all the spotweld bumps on my welding table. (clip) ^^^^^^^^^^^^^^^^^ Well, I can help you solve that part of it. Place a coupon of steel on the bench, next to the work, and start your welds on THAT.
Reply to
Leo Lichtman
Based on my fumbling around blindly when I was first getting started..it sounds like a feeder problem particularly with that burnback. Or...your gas solenoid is slow in opening. If you start the arc without gas..wierd things happen
I think Ive done everything wrong at least twice..slow learner when I self taught...sigh
Put the old gun back on and see what happens?
Gunner
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Reply to
Gunner
SNIP
Reply to
Rod Ryker
First, go with the knowns:
Revert to an older gun that worked. Theoretically, this will tell you if it is the new gun or not.
If the old gun works fine, problem solved. Toss the new gun. If the old gun suffers the same problems, we gotta go one step at a time.
I've had this problem too often with my MIG. The first thing you should do is put in a new liner. Your liner could be kinked or clogged or worn. I have a feeling this is your problem (assuming you are using a new contact tip of the correct size). Next, play with your tension and drive rolls.
I have a Miller 250X, and I recently (after 6 years of fighting it), disabled the "hot start" feature, because it was burning to hot and fusing the wire to the tip. This helped my problem, but I don't think it is the same for your machine. But who knows?
Start with the old gun.
Best of luck.
Smyths
Rod Ryker wrote: > outofstepper wrote: > > Greets all.. I've got a 3ph 300A Italian-made Weldtronic mig welder. > > Have had it a few years now, gone through 2 or 3 replacement guns, > > without any problems. Lately, however, its been acting strange: poor > > starting.. 2 out of 5 times when i start a bead the wire "blows" and > > melts back into the nozzle. been losing more time fishing the thing > > back out.. usually shaking the gun around (i try to not bang it) breaks > > the wire free and i'm good to go again. > SNIP
Reply to
smyths
thanks, all.. as soon as i get some free time with the machine i'll give it the once-over. old gun is gone (they always spark under the hot clamp and blow holes in the brass fitting -- yep, they've always been tight), but i think i have a replacement liner somewhere.
-tony
Reply to
outofstepper

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