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Straight answers on choosing, setting up and troubleshooting self-shielded gasless flux-cored wire.
Most gasless wire runs on electrode negative, also called straight polarity. On many machines the polarity is changed inside the case near the drive rolls by swapping the lead from one terminal to the other, so it is worth checking the machine manual.Some wires are made for the opposite polarity, so always follow the wire maker's recommendation on the reel or data sheet. Running the wrong polarity gives a harsh, spattery arc, poor bead shape and unreliable results.
It is a public classification that describes the wire. In general terms the E means an electrode, the 7 relates to its tensile strength class, the 1 means it can be used in all positions, the T means it is a tubular (flux-cored) wire, and the last number describes the type of flux and the shielding and polarity it is designed for. An -11 wire is typically self-shielded and run on electrode negative.Check the standard or the maker's data sheet for the full detail, and use the classification to compare wires from different makers rather than relying on the product name.
Stickout is the length of wire between the contact tip and the work. Gasless wire normally runs with a longer stickout than solid MIG wire; around twice as long is a common rule of thumb. A longer stickout preheats the wire and keeps the flux working properly.Too long a stickout causes porosity, an unstable arc and burnback to the tip, while too short gives excessive spatter and overheats the tip. Follow the wire's data sheet for the right range and adjust in small steps.
Flux-cored wire is a soft tube, so it can be squashed by too much pressure. Knurled (grooved) drive rolls grip it well without crushing it, whereas the smooth V-groove rolls used for solid steel wire may slip.Set the drive roll tension just high enough to feed the wire without slipping, as set out in the machine manual. A crushed or flattened wire shows as erratic feeding and a rough arc. Match the roll groove to the wire diameter.