but welding 16 -18 guage steel where did I mess up?

admin

I am doing some patch panel welding on my truck and tried to do some butt welding of a patch of metal to existing steel. I used the stitch method but blew holes though the steel. Stitch welded works fine on lap welds. Now some one told me to put some copper sheet or bar behind the butt weld to absorb the heat. Does this work well to prevent bad weld jobs like this one?
Reply:Get the metal edges as tight as possible.  There's not a lot of material to begin with and you can't weld air.The copper (or aluminum) backing plate acts as a heat sink to keep your workpiece from getting too hot to blow through.  The different material won't get welded to your steel and your puddle stays put.Try spot welding/tacking instead of running a continuous bead.Also try angling the tip instead of pointing straight into the joint.The more heat on your workpiece the greater the chance you'll blow through.  Minimize that with a variety of techniques.Lincoln AC225 and CartLincoln WeldPak HD and CartOne hand
Reply:backing strips and small dia 6010 would be my vote to save yourself alot of headache
Reply:Monica's right, the tighter the better!
Reply:what are you using? settings, machine, etc?There are no problems. There are only solutions. It's your duty to determine the right one.Hobart Handler 210Airco 225 Amp MSM Stinger
Reply:you can use one of these http://www.harborfreight.com/welding-spoon-66785.htmlyour pieces otherwise need to be basically touching on material that thin. Unless you are TIG or OA welding   also u need to probably use .023 wireI believe you are MIG welding this.  you may also be running too hot.   what machine are you using? put some filler metal in the gap such as 6010 that was mentioned with the flux removed.Last edited by soutthpaw; 10-16-2011 at 04:28 PM.Tiger Sales:  AHP Distributor    www.tigersalesco.comAHP200x; AHP 160ST; MM350P,  Spoolmatic 30A; Everlast PowerTig 185; Thermal Dynamics 60i plasma.  For Sale:  Cobra Mig 250 w/ Push-pull gun.  Lincoln Wirematic 250
Reply:In the red circled area of your image, it appears there'sfuel, fuel vapor hoses and electrical cabling, behind the weld area.Suggest some shielding to keep hot boogers from gettingat those  things, or one can have more excitement thanthey've bargained for.http://weldingweb.com/attachment.php...1&d=1318797888 Attached ImagesBlackbird
Reply:Yup, you got some fair gaps but it is not a total killer.Already in the above posts they have hit a bunch of points to consider.You say the stitch method but I'm not totally sure what you are doing or using. If you have the Eastman stitcher attachment for a stick welder that helps a lot. Use the 1/16" rods that say quick or easy strike most today will be those. In general if you do have a gap, you must use some type of backer. Anything that will not be welded into the job. Lots of things will work, the backer tools which are usually copper. Anything brick like or ceramic also works. I like a particular type brick if I have the room, if not I will try using ceramic tile. You want to be able to clamp it in tight and form a bottom to prevent blowing thru. You can "flow the metal" within that gap. Maybe preheat anything ceramic to get rid of any moisture within it.Again in general your angle should not be very high. Depends on what I am trying to do, I angle it down a lot and in line if I want to do a sort of normal bead. Sometimes you angle a bit off to one side. You can just do a bunch of smaller tacks and then come back and weld over them. Going vertical can be more tricky and usually you don't try to do longer beads at first. With the right  setup the beads tend to be flatter anyway. Not whole bunches of metal involved.I would start with getting something to form a backing, then experiment a bit and see how it goes. That makes everything so much better. Lots of it is experience based for what works in what situation.Sometimes I leave that wee gap on purpose in some jobs. I want to try to fill it only and just bond into the edges. Must have a backer fit very tight, some very thin stuff and I can't get inside to sand / grind after the fact. Some maybe a bit difficult to describe.
Reply:You can also try the old trick of backing those gaps with other steel strips. Maybe something like 1/4" wide or so, they become part of the job and stay in there.Best if you can make them out of heavier sheet metal than what you are doing. Can just piece it as needed. Looks a bit of a mess but if you can't see it, so be it. Jury rigging in style.Can do it, even if there is not much of a gap. Try not to weld directly into the gap, be a bit off to a side, if that makes sense.
Reply:Can't weld air. Never could never will. In my early days I sure tried.Copper or steel backing will work. BTW you do not have a butt joint you showed pictures of an open root joint. To be a butt joint they would need to be with out gap.Last edited by Fat Bastard; 10-16-2011 at 06:05 PM.
Reply:One more idea.You can take some smaller diameter copper tubing, crush it flat, shape that into a U or V shape, try to stick / clamp  it in tight enough to have no air gaps anywhere. The copper will bend in if you use the soft stuff, the backing piece can be fairly small if needed. If you ruin, melt part of it who cares.Lots of ways to skin the same goat. Usually I never buy anything. Lots of home made whatevers with what ever is on hand. One thing don't work try another. Free is good.I like to use a belt sander to clean it up after, grinders are usually too aggressive. Pick the right belt for the job, maybe changing it as you go.
Reply:And even one last idea.That is fair thick sheet metal.I have a box with all the small bits and pieces. I never throw anything away. I would find very thin pieces of steel just the right size to fit into those gaps. Maybe something more like metal shavings. Then I would take auto body tools and work the fills to hammer them into a bit of solid fill. Done right you should be able cause them to meld into the right shape / mass, sort of a swaging or rounding over technique.Then just weld over that area. Back it up if needed but it shouldn't require it.Think about it enough like I would do it. Yeah, that would be my prime first method. Junk box to the rescue. Auto body tools lend themselves well to that approach too. Reshaping metal for a purpose.