Flux core set up

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I recently bought a role of flux core wire and i was wondering how crucial it was to have knuckled drive rolls i know it helps not to squash the wire etc but is it really needed and also does it require diffrent contact tips  because i was told lets say 0.9mm flux wire is really about 1mm because of the seam, I would really appreciate any help.Thanks SteveCigweld Transmig 265seBoc 140amp StickBoss 200amp AC/DC TIGLincoln Electric Invertec V260-S
Reply:You can run it with smooth groove drive rolls but they tend to slip if not adjusted tight enough, whereas the knurled groove rolls don't slip when adjusted only lightly.You don't need any special contact tip, just use the size that matches the wire size.   I use .035 tips with .035 wire, .045 tips with .045 wire and 1/16 tips with 1/16 wire.  You may want to get the fluxcore diffuser shield or tip holder, if they make it for your torch, as fluxcore spatters a bit and is hard on the gas nozzle if you run with it on and hard on the diffuser if you run with the nozzle off.MM350P/Python/Q300MM175/Q300DialarcHFHTP MIG200PowCon300SMHypertherm380ThermalArc185Purox oaF350CrewCab4x4LoadNGo utilitybedBobcat250XMT304/Optima/SpoolmaticSuitcase12RC/Q300Suitcase8RC/Q400Passport/Q300Smith op
Reply:If you've got a short gun, say 6 or 8' it probably won't affect you too much to use smooth rolls. Crushing the wire is a concern, so keep your drive roll tension at the minimum that works.   For 12' or 15' guns, I'd say you should pay for the knurled drive rolls.  Otherwise you're bound to have wire feeding issues.  Buy the right contact tips for the wire diameter.  This will cause you nothing but grief in the long run.  Remember that those tips are a consumable, they wear out.  If the hole in the tip isn't round, replace it.I've seen feeding issues with small dia wire in guns with large OD liners.  Make sure your liner is the right size, or no more than the next size up when you're running thin wire.  Thin wire will S-curve inside a too large liner and you'll get feeding issues. Originally Posted by BozzzaI recently bought a role of flux core wire and i was wondering how crucial it was to have knuckled drive rolls i know it helps not to squash the wire etc but is it really needed and also does it require diffrent contact tips  because i was told lets say 0.9mm flux wire is really about 1mm because of the seam, I would really appreciate any help.Thanks Steve
Reply:Match the contact tip size to the wire.  About the only time an 'upsized' tip might be needed is for aluminum wire, as aluminum expands thermally more than steel (FCAW or solid) wire or the copper tip hole do.For short gun cable lengths (about 10 ft or so) and if you don't have the cable zigging and zagging too much, the plain grooved drive rollers -usually- work OK.  If you have feeding issues with the plain grooved rollers, then get the knurled rollers (or straighten the cable   ).+1 on getting a 'flux-core' nozzle if available.  That type of nozzle is less bulky than a MIG nozzle and it protects the nozzle threads and the diffuser from the FCAW spatter.  Lincoln makes such nozzles for their 'smaller' guns (the less than 300 amp models, it looks like), don't know about other brands.  The best laid schemes ... Gang oft agley ...
Reply:bernard makes flux cored adapters for their Q guns.  Take off the gas diffuser, install the centerfire tip, and screw on the cap that holds the tip in place.  Works nice, lasts a long time. (so long as nobody uses a wrench to over tighten them.     ) Originally Posted by MoonRiseMatch the contact tip size to the wire.  About the only time an 'upsized' tip might be needed is for aluminum wire, as aluminum expands thermally more than steel (FCAW or solid) wire or the copper tip hole do.For short gun cable lengths (about 10 ft or so) and if you don't have the cable zigging and zagging too much, the plain grooved drive rollers -usually- work OK.  If you have feeding issues with the plain grooved rollers, then get the knurled rollers (or straighten the cable   ).+1 on getting a 'flux-core' nozzle if available.  That type of nozzle is less bulky than a MIG nozzle and it protects the nozzle threads and the diffuser from the FCAW spatter.  Lincoln makes such nozzles for their 'smaller' guns (the less than 300 amp models, it looks like), don't know about other brands.