Fornew welder

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I recently bought a old forney welder ac/dc, to help me with a welding test. The test is 3/8 plate with 7018 open butt. I have some experience welding but need to work on my root pass. Burning 7018 I can't seem to get the arc going on the forney welder. Any ideas or tips would be greatly appreciated.
Reply:First is do you have it setup for DC not AC?Second is do you have any other type of rod to Test machine functionality?Third would be to check the open circuit voltage on the AC outputs, then check it on the DC outputs.There is a possibility that the machine has an internal failure to switch from AC to DC - switch, cross wire issue, bad diodes.
Reply:Originally Posted by Jason HansenThe test is 3/8 plate with 7018 open butt.
Reply:I had the leads in the in the DC side. I have 6013 that came with the welder bUT haven't tried it yet.Yes 7018 open butt for fagen Inc's structural test.
Reply:Newer Forney than I'm used to, but still quite old. I would speculate and say bad diode(s) if the machine works in AC but not DC. Follow drujinin's recommendation for testing and you should come up with the solution. With just an on/off switch, I doubt there is any wiring problem.Lincoln PrecisionTig 275Miller 251Miller DialArc 250Bridgeport millHossfeld bender & diesLogan shaperJet 14 X 40 latheSouth Bend 9" 'C'Hypertherm 900Ellis 3000 band saw21"Royersford ExcelsiorTwo shops, still too many tools.
Reply:"Burning 7018 I can't seem to get the arc going on the forney welder." Are you saying it won't strike an arc at all, or you're having trouble with the arc? Are you using 7018 rods for DC? They do make AC 7018 rods. Do you have the correct polarity for the DC setting? Good ground connection?
Reply:In my 30 plus years of welding, if I buy an old used welder the first thing I do is replace the leads. Over the years Iv'e learned that it makes a huge difference in how old used welders run. If your stinger is getting hot after a half dozen rods it's building up resistance and the cables should be replaced. Also, take a volt meter and measure the voltage at the welder, it should be around 80 volts, then measure the voltage at the ground clamp and stinger. If you have a ohm meter measure the resistance on the cables and if it's to high that might be your problem. It's not to common for old transformer welders to have anything wrong with them as there's not much to go wrong.
Reply:first off its Forney, company started in 1932.
Reply:I will try the 6013 when I get home. Do I use ac or dc for that.
Reply:If you want to do a test with 7018 forget 6013, totally different. Most welders prefer to stay away from 6013 because it is the weakest of all welding rods.
Reply:Some of them old welders were not great at running 7018, even in DC. See how it runs those 6013 rods in DC +.  It could just be your technique.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Originally Posted by snoeproeSome of them old welders were not great at running 7018, even in DC.
Reply:What is dc+?
Reply:Originally Posted by Jason HansenWhat is dc+?
Reply:dc+ means "dc with electrode positive" = DCEP = "reverse polarity"dc- means "dc with electrode negative" = DCEN = "standard polarity"ac means "all of the above"
Reply:So basically he's telling you the difference will be whether or not you plug your hot electrode into the red or black outlet on the DC side of your machine.250 amp Miller DialArc AC/DC StickF-225 amp Forney AC Stick230 amp Sears AC StickLincoln 180C MIGVictor Medalist 350 O/ACut 50 PlasmaLes
Reply:I have gotten figured  out. Thank you every one for the help. My experience with welders till now was with a miller trail blazer welder generator. I would help the welder run his leads and plugged the stinger into the positive and ground to negative and set it for tig or stick. So when I got this welder I did the same. I couldn't get an arc to stay because I was already in dc+. I ha e gotten home switched the leads around and it is working much better.
Reply:You should be running stick in DC+ (reverse) polarity.DC tig is DC- (straight) polarity.Last edited by snoeproe; 06-27-2015 at 10:48 PM.JasonLincoln Idealarc 250 stick/tigThermal Dynamics Cutmaster 52Miller Bobcat 250Torchmate CNC tableThermal Arc Hefty 2Ironworkers Local 720
Reply:Buy some 7018 1/8 AC Lincoln rod at Home Depot or Lowes ,should run on ac/dc ,practice makes it work. Hirshfield Industries ,the largest fabricator uses it for all tacking!