Mig Ground Heating Up

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Quick question,I have a MM 251, and today I have been welding at 18 V a bunch of stuff.  Anyway, it seems I can only weld 3 or 4 items (each item consists of many welds) before my ground gets so hot (within 1-1.5 feet of the clamp) that it starts to melt the sleeve/insulating jacket around the wire.  I let it cool down and can really heat it up again.  I know I can push this welder much hotter than that..... but makes me think something is wrong.  Your thoughts?  The Lord has declared, "This is my work and my glory--to bring to pass the immortality and eternal life of man"  Moses 1:39Link: My name is John, and I am a member of The Church of Jesus Christ of Latter-Day Saints.-- ColdCreekWorks.com --
Reply:1) Bad connection between the cable and clamp2) Weak clamp spring (poor connection between clamp and work)3) Work material not cleaned of rust, dirt, mill scale, etc at clamp pointHeat like that is typically the result of a bad connection as a result of one of the above - speaking from experience.MM200 w/Spoolmatic 1Syncrowave 180SDBobcat 225G Plus - LP/NGMUTT Suitcase WirefeederWC-1S/Spoolmatic 1HF-251D-1PakMaster 100XL '68 Red Face Code #6633 projectStar Jet 21-110Save Second Base!
Reply:Originally Posted by jdh239Quick question,I have a MM 251, and today I have been welding at 18 V a bunch of stuff.  Anyway, it seems I can only weld 3 or 4 items (each item consists of many welds) before my ground gets so hot (within 1-1.5 feet of the clamp) that it starts to melt the sleeve/insulating jacket around the wire.  I let it cool down and can really heat it up again.  I know I can push this welder much hotter than that..... but makes me think something is wrong.  Your thoughts?
Reply:Thanks all.  I haven't cleaned off the mill scale, so that may be the culprit.  I tried reclamping the piece directly instead of via the table, and that didn't make much difference.  Would take too long to clean off the mill scale (no rust), but I just let it cool down a few times and finished up for the night.The Lord has declared, "This is my work and my glory--to bring to pass the immortality and eternal life of man"  Moses 1:39Link: My name is John, and I am a member of The Church of Jesus Christ of Latter-Day Saints.-- ColdCreekWorks.com --
Reply:Start welding with everything cold.  Check frequently for heat.  The first spot to get hot is where the problem is.  Mill scale doesn't usually cause much trouble, but it wouldn't hurt to grind where the clamp is.My name's not Jim....
Reply:I experienced the same problem with my MM180 a while back. The problem appeard to be selection 2 in Duane's list. The Clamps that Miller puts on these smaller machines are cheap. I put a Tweeco clamp on it and the problem was solved.
Reply:Try cleaning the contact surface of your clamp.  Sometimes that can contribute to the problemGordie -- "I believe you understand what you think I said, but I'm not sure you realize that what you heard is not what I meant."
Reply:Follow the ground all the way into the machine and make sure its clean at both ends.Welding Supervisor Department of Corrections.
Reply:I like to use a pair of size 10 vicegrips and clamp them tight and wiggle them back and forth a couple times then clamp my ground the the pliers.....just my $.02 from welding on old rusty junk people bring throuh my door -DoogieMiller 350PMiller Trailblazer 325 EFI w/ Excel PowerLincoln LN25 suitcase welderXMT 304/22a feederMiller Syncrowave 350LXMiller EconotigHobart Handler 140(2) Uni-Hydro 42-14Hypertherm 65 plasmaWEBB Gap bed lathe
Reply:Restrictions in flow cause heat. Your electrons are hitting a restriction, most always 1 of 2 things connections and connections sometimes it might be the connections. Dirty, loose or it might be loose or dirty. lol
Reply:Originally Posted by Fat BastardRestrictions in flow cause heat. Your electrons are hitting a restriction, most always 1 of 2 things connections and connections sometimes it might be the connections. Dirty, loose or it might be loose or dirty. lol
Reply:: Originally Posted by Oldiron2According to the media (and brucer   too?), it must be some loose Republicans......
Reply:FB>>>>>>>>>> Love the signature line!Learning one rod at a time
Reply:Junk the sheet metal ground clamp and get the cast brass one with the copper rivet.  You can take your existing one and clean the contact surfaces and screw arond with it, but you will have the same trouble in a little while. Replace it with a good one and you will neverhave it again.