175i Inverter Mig with fluxcore wire

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Hi, first post.I have done a lot of welding in my time, but by no means consider myself an expert.I have a 415v three phase 350amp mig of my own that has served me very well in both light and heavy welding work. I usually run .9mm mild steel wire and have no problems getting a good weld. I recently was asked to do a job for someone who had just purchased a Cigweld 175i combination Mig/Tig/Arc welder and the idea was I would set up his welder and use it to do some fabrication work for him. As the owner had no gas he had a role of .8mm fluxcore wire. After a bit of adjustment I had it welding pretty well and although smoky and dirty the welds came up pretty decent, until.....I started to get all sorts of inconsistencies in the operation where there seemed to be a loss of power, or the wire would burn back to the torch when it was welding fine before.I eventually gave up and welded the heavier work with the stick. I tried several time to go back to the mig welding and it would be fine for maybe ten welds then become unstable again with the wire burning back to the torch or the wire feed being erratic. There seemed to be no way of improvement by adjusting wire speed or amps. I have not had much experience with flux cored wire before so I am wondering if I am missing some technique that could overcome this. I ended up getting my own mig to finish the job as I was getting nowhere. Any help would be appreciatedBazLast edited by thebaz; 08-10-2013 at 06:06 AM.
Reply:Most problems with mig turn out to be wire feed problems.Could be a kinked liner ,bad tip,or wrong groove in the drive rollers,but the most common seems to be drive rollers adjusted too tight.
Reply:Duty cycle?? A 175 amp unit is one of those just big enough to do a little bit of a big job. What amps are you running ? Look up the wire at the manufacturers site, see what amperage you're laying down at the wire speed you are running."The things that will destroy America are prosperity at any price, peace at any price, safety first instead of duty first, the love of soft living and the get rich quick theory of life." -Theodore Roosevelt
Reply:Thanks for the replies,I would doubt it is a duty cycle thing as the same problem was there when welding 2mm with amp setting around 6 on a scale of 10. The roller was definitely in the .8mm position unless has been stamped incorrectly which is highly possible. I did put more tension on the roller when i started having problems but backed it off later but there was no change.I have never noticed any problems myself from over tensioned rollers, but this may not be as noticeable with the thicker wire I am used to running.What are the signs that the wire is is too tight and how do you judge the best tension?I will check the drive roller under a magnifying glass and see if it is incorrectly labeled.Baz
Reply:For flux core wire, one of the drive rollers should be knurled. I don't know what rollers are included with that machine, you may need to buy an extra one. Also, the drive-roll tension should be less for flux core than for hard wire. If the tension is too high it will deform the wire, making it hard to feed.Next, make sure that the tension on the spool brake is not too high. It should be just tight enough to prevent the wire from over-running when the machine stops feeding. If it is too tight the drive rolls will slip which will cause the problems you are experiencing.JohnA few weldersA lot of hammersA whole lot of C-clamps
Reply:Flux core wire is as soft as mud,it is just a metal shell wrapped around the flux.If the feed wheels are adjusted too tight the wire gets squeezed into an oval shape and will drag through the round hole in the tip,and it will get worse when the tip heats up.The other thing that happens is that once you get it adjusted to the proper tension for flux core,is that any bad spots or kinks in the liner will cause feed trouble.A piece of wire should have almost zero drag through a properly functioning liner.
Reply:Thanks for the informative replies. That makes a lot of sense now. I will check the feed rollers and try a minimum tension.Baz
Reply:tension on any wire should just be enough to get it to feedMiller Xmt 350Lincoln Ln-25Ahp 200xSmith Gas Mixer AR/HTig is my Kung FuThrowing down dimes and weaving aboutInstagram http://instagram.com/[email protected]