vertebraille Posted January 17, 2011 Share Posted January 17, 2011 Hi, I have a Millermatic 130xp mig welder running .030 solid wire and a CO2 Shield gas through. Im having some issues with blowthrough. The welder has four amperage settings. 1 and 2 are just too low and 3 is having issues with not penetrating the top plate but four just blows through without blinking...? Im running my CO2 at about 30-35psi... If anyone has any info or tips to correct these issue I would appreciate it greatly. Oh, I'm currently seam welding the front strut towers. Just to give you and idea of material thickness. Thanks, Murph Also: I've been playing with my wire feed speed but it's not seeming to have much effect on the above problem but just for infos sake the welder has settings from 10-90 for wire speed infinetly adjustable between those points. Quote Link to comment Share on other sites More sharing options...
pat1 Posted January 17, 2011 Share Posted January 17, 2011 use a smaller wire like .23 and lower the gas, your just wasting gas with anything over 10-15. You need to stitch weld. This datsun sheet metal is not the easiest to weld. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted January 17, 2011 Share Posted January 17, 2011 (edited) Try 3.25 and about 2-3 on the wirespeed for Datsun sheetmetal. You have to keep moving, but my Millermatic 135 doesn't blow through at that setting unless I do something wrong. If you're going around the top of the strut towers, there are two pieces of metal in there. There is a top piece of sheet which is very thin, and the strut top itself underneath which is probably .100" thick. If you're trying to weld to the thicker stuff you need to use a setting that will penetrate the thicker material. Without looking, my gut says put the heat on 6 and the wire speed on 5 (you can check the inside of the access panel to verify that). Then you'll blow through the thin stuff almost instantly and have to work your way back to the thin layer with the puddle. Edited January 17, 2011 by JMortensen Quote Link to comment Share on other sites More sharing options...
vertebraille Posted January 17, 2011 Author Share Posted January 17, 2011 Try 3.25 and about 2-3 on the wirespeed for Datsun sheetmetal. You have to keep moving, but my Millermatic 135 doesn't blow through at that setting unless I do something wrong. If you're going around the top of the strut towers, there are two pieces of metal in there. There is a top piece of sheet which is very thin, and the strut top itself underneath which is probably .100" thick. If you're trying to weld to the thicker stuff you need to use a setting that will penetrate the thicker material. Without looking, my gut says put the heat on 6 and the wire speed on 5 (you can check the inside of the access panel to verify that). Then you'll blow through the thin stuff almost instantly and have to work your way back to the thin layer with the puddle. Sweet thanks. I turned down the gas and shortened my stitch welds a little. Little less heat in one spot. I just welded a cutout steering column bearing from a 99up cobra into a 5.0 for a friend and it went just fine. Tomorrow I will try the 280's towers again. I think Im going to cut out the tops and weld in some camber plates. Thanks for the tips guys. Murph Quote Link to comment Share on other sites More sharing options...
ozzzzz Posted January 17, 2011 Share Posted January 17, 2011 Sweet thanks. I turned down the gas and shortened my stitch welds a little. Little less heat in one spot. I just welded a cutout steering column bearing from a 99up cobra into a 5.0 for a friend and it went just fine. Tomorrow I will try the 280's towers again. I think Im going to cut out the tops and weld in some camber plates. Thanks for the tips guys. Murph How much stick out (wire that is) are you using? This is critical for penetration or lack of or too much. Increasing wire speed increases amps. The other knob adjusts voltage. Are you pushing or pulling the wire? This also makes a difference. Push the wire and shorten stick out to decrease penetraction and it will also widen bead slightly. Is the machine set on DCEP or DCEN. DCEN will give the least amount penetration with a tall bead if you are using solid core wire. Flux core is a different story. As someone stated above go to a smaller gauge wire for thinner sheetmetal. You can also use TIG rod along with the larger wire. Place the Tig rod against the sheetmetal where you want to weld. Now spot weld where the TIG rod is touching the sheetmetal. Move over a little and repeat. The TIG rod will help to prevent blow through. It also works great for filling in holes or chasing holes in rusted metal. Your bead will be a series of overlapping spot welds(this method also works without the addition of the TIG rod). Quote Link to comment Share on other sites More sharing options...
Brad-ManQ45 Posted January 18, 2011 Share Posted January 18, 2011 Also, switching to C25 will help. CO2 is hotter than an argon/CO2 mix... Quote Link to comment Share on other sites More sharing options...
vertebraille Posted January 18, 2011 Author Share Posted January 18, 2011 (edited) I generally tend to drag the tip from the puddle. Being left handed this make it a little easier for me to stay straight. I also have roughly a 3/8" "stick out" which I thought was about normal. I've managed to get the blow through from happening by moving just a little faster. however, now the welder is popping more than I think it should.... Oh, just in case someone decides to ask, I cheched the manual and the welder cover and my polarity is correct. Murph Also: the manual does not cover "datsun super-variable thickness steel" so dont even look. I figure, that by the time I finish seam welding these front strut towers, I'll have my issues figured out and one hell of a ugly fender well. Hey, if it runs who cares right? Edited January 18, 2011 by vertebraille Quote Link to comment Share on other sites More sharing options...
rjstcroix Posted February 2, 2011 Share Posted February 2, 2011 Hey, An issue we had when seam welding was the minor presence of crap/crud in the seam. The weld would pop, hiss and sputter like mad. Before some of you jump to conclusions and say "you must only weld clean metal" I should let you know that the metal was sand blasted bare, wire wheeled, scraped and picked clean then sprayed with some degreaser before a final cleaning of the base metal. And, yes, the welder was setup right so no tree to bark up there either. Even after going through all that effort there was still enough crud in the minute crevasses to cause a poor weld. In the end we decided to minimize the amount of seam welding just because of the poor end result. There was some thought and discussion that our problem could have been as a result of factory applied seam sealer and undercoat that is present in the lap joints of the seams which caused the crappy welding. Either way we adjusted our build plan as a result of the problems we encountered. The 0.30 wire is too big for the delicate body metal of Datsun. 0.23 solid wire with about 20lbs. CO2 gas pressure, Voltage on 2 and wire speed on 3 with our Lincoln 180 made for a very consistent and controllable weld. Also a pre-heating of the base metal with a propane torch liberated moisture and minimized the cold start issues on the bead. Regards, RSC Quote Link to comment Share on other sites More sharing options...
JMortensen Posted February 2, 2011 Share Posted February 2, 2011 It's seam sealer. I pulled up the top panel and scraped the inside with a pick, then hammered it back down and welded. The inside of the wheel wells was especially tough, but you can do it and get a decent result, just takes a lot of time and effort, and I'm not sure the payout is worth it in retrospect. Quote Link to comment Share on other sites More sharing options...
vertebraille Posted February 3, 2011 Author Share Posted February 3, 2011 It's seam sealer. I pulled up the top panel and scraped the inside with a pick, then hammered it back down and welded. The inside of the wheel wells was especially tough, but you can do it and get a decent result, just takes a lot of time and effort, and I'm not sure the payout is worth it in retrospect. I've started doing the same thing. Peeling up the edge and cleaning the s**t out of it then tapping it back down and welding. Time consuming and ugly as sinning with a one legged hooker.... Since weight isn't an issue to me I'm probably going to lead the seams and clean them up a bit after their all welded, before it gets painted. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted March 7, 2011 Share Posted March 7, 2011 I'm having some mild issues with mine as well. Could someone expound on using the tig rod with the mig to assist in cooling. I can't turn the voltage below 1, have had it set around 2. I am running argon/co2 about 10-15psi. Wire speed between 2-6 doesn't seem to make much difference with .023. I've been practicing filling small holes using scrap metal around 20gauge. I started fine then around edge of hole it just burned right through, I could build the bead a little and got good penetration but it warped too much. Quote Link to comment Share on other sites More sharing options...
mario_82_ZXT Posted March 9, 2011 Share Posted March 9, 2011 Pulse it. Just lay a little tack, then again, and again, and again. If you can find a chunk of copper to put behind it, it will help a lot. Quote Link to comment Share on other sites More sharing options...
emeraldlion Posted March 9, 2011 Share Posted March 9, 2011 Yeah, I got out last night and tried some of the tips listed above. Decreased wire speed, pushed the wire instead of pulling, and then tried the multiple tacks method on the scraps and it definitely worked better than my initial attempt. I will be working on the door so really can't get to the inside very well, but will try the copper on the fender and quarter. Quote Link to comment Share on other sites More sharing options...
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