Technical Welding help/grade

Ok, I am setting up to weld in a patch to my toe board for my 57 ford wagon. To that end I am beginning to practice my technique. Now I think there should be a weld all of the way through the gap of two pieces if I am not wrong.

Well, I ain’t getting it. I do a relatively nice bead on top but it doesn’t seem to penetrate all of the way through. I have tried more heat/less heat; faster/slower nothing seems to get the weld all of the way through.

The metal I am using is 18/9 gauge that is a stamped piece for this car and some sheet steel that is about 16 gauge. And in my exuberance to weld I forgot to clean the metal off of any oils etc.-there is no rust on either piece. Tell me what I am doing wrong and how to fix it please. I would like to get going on this project again now that it is above freezing in the garage.

thank for the help.

 

Possibly a bit cold on the settings, which sometimes can be a tightrope, meaning full penetration without blowouts.

 

Needs more heat and I’d tighten up the gaps. Looks like your trying to mate different gages, all the temp seems to be going in one panel

 

How big is the wire you using?

 

I'm no pro but that said, I like leaving a bit more room between the panels. About the thickness of a cutoff blade, and then I fill that void. I crank up the heat until I burn through and then turn it down a bit, but heat and your speed is critically tied together. Keep the wire speed low or you end up with a caterpillar like in your photo. I like making little cursive "e"s with my MIG, touching both panels, and I work the puddle away from me if possible. If you're not seeing the puddle, it because your not hot enough to make one. Hope this helps.

A friend told me once you can hand a MIG torch to 20 different welders and you will see 30 different techniques. Find yours and have fun. I love melting stuff together.

 

Slightly more heat. No gap. If still too buggery, slightly more heat.

 

Butt welding sheet metal with a MIG is challenging, be prepared to spend a while getting your technique figured out. Getting full penetration and not much bead on top is difficult.

I would stitch weld...weld for about 1/4" to 1/2" long then skip ahead an inch, and weld another stitch, etc. Then go back and do that again between stitches, and then yet again, till it's filled in. This is a way to control heat.

 

All good advice above. You need more heat

I align with Bandit Billy, I have similar techniques.

I will add that you can push a weld or pull one. Meaning, aiming the wire and pushing the puddle towards the gap away from the puddle or aiming the wire towards the puddle and dragging the puddle backwards away from the puddle. I like the second technique with sheet metal because the majority of the heat is aimed towards the weld as you go. You can let off the gun and sit still and not lift the hood for a few seconds to let things cool off and then continue on. But you can’t weld it in one continuous pass, you have to jump around

 

Again as bandit Billy stated above everyone has their own technique.

I run a little hot then I back off of wire speed until I start wanting to blow holes then up the wire a little bit.

One technique I use on wider gaps is I just do a very fast small weld on one side of the gap, let it cool, then grab the other side and on the weld I pull the puddle into the previous weld I made. This makes one solid weld bead between both sides.

I do several of these down the gap evenly spaced. Then I go back and start the next weld bead right at my starter beads. Almost looks like I'm tig welding. Just small quick tacks/welds and work back and forth between all the spot/tack welds until I've ran a complete seam

When I've got a long tight seam that I can start and not have to stop it almost looks like a tig weld down its entirety.

Bump heat, back off wire speed then work wire speed up a little at a time until your happy.....

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Thank you, I will go make some more test runs. I am not concerned about warpage-yet. I am just trying to get technique down. I will bump the heat up a notch to see what happens.

and of course, right after I post this I start watching the puddle more and spreading the heat out to both pieces and it starts looking better. Go figure. I will post back soon with updates that are hopefully improvements.

 

If you get good penetration with the amps up but a bit of burn through, use a piece of copper held firmly against the back of your weld area, it’ll prevent burn through and take a bit of heat away.

 

No gap! If you run a gap, and you don't get the wire hitting both sides of the steel, only one side gets all the heat, and blows through. Then you have to drop the heat setting, and get no penetration. No gap, and then, work on your heat and speed settings, as well as your aim! Takes practice!

 

The bead being that tall could mean too much wire feed speed, and/or too slow travel speed, and/or too low angle. Stand the gun up more (so you are driving the wire into the base metal) and get your head down lower so you can see the bead.

 

Tack the piece in all around. Bounce around all over the panel you're fitting to keep the heat spread out over the entire panel rather than concentrated in one area to prevent warping and distortion. Take a break and let it cool, then tack in between the previous tack welds, take a break, and repeat until the gaps between the tack welds are less than 1/2" or so. Then you can either continue the tacks, or fill the small gaps with short beads.

Laying down a bead on thin sheet metal will put too much heat into that thin material and you'll blow holes through the metal and now you have to chase that hole until you fill it.

I'm not formally trained or anything, but rather self taught and this method has worked for me.

Example of thicker rocker panel to thinner floor pan.

 

This is some 20 ga. butt welded with good penetration. When possible I back it up with a piece of copper clamped in place to help control the heat. I clamp every thing I can . I clean the metal shiny bright and keep a really short stick out with the wire ( less than a 1/4 in. I come straight down on top of the piece I am welding and hit the trigger for 2 seconds. That way you can keep the heat up with no burn through. I would just spot all the together, you still end up with a solid welded seam just a spot at the time

 

A slight variation to what already been said, improve your aim and / or have the torch square to both panels, as in side to side. Some angle along the bead is required, but not side to side.
Also, the edges of each panel should be nice and tidy. I think I can see the remains of cuts made with a cutting disc, those razor sharp burrs. File / grind/ sand / deburr tool.

Chris

 

I'm a welder by trade but I mostly work in heavy structural and pipe with a little sheet metal thrown in. With MIG welding, you typically get better results with a gap. You are using the filler metal to create the weld puddle and there needs to be somewhere for that filler to go. To cold, to much wire speed, or not enough gap and it will hump up. You can also have any combination of those working against you. With TIG, a tighter gap works better as you are creating the puddle before you add the filler. As to technique, play around until you find what works best for you.

Cleanliness plays a big part as well. You want the metal clean, bright, and shiny. It's also not a bad idea to wipe down the pieces with a solvent like alcohol, acetone, or non chlorinated brake cleaner. Good luck.

 

Some good advice above. The gap needs to be about the thickness of your wire, if you're looking for full penetration.
You can get away with a little more if you can back it up with copper. If you are going to use the spot tack method, the heat and the wire speed should be higher than you could ever hope to be able to run a bead. Whatever method you try, do skip around and do not concentrate a lot of heat in one place.
Id recommend practicing on some scrap first. Good Luck

 

Like has been said, different people use different techniques. Some of the higher dollar Mig welders have a pulse feature incorporated in them which allows some cooling as the weld is made. What I do is forget about trying to make a nice weld bead on sheetmetal. You have to jump around on the panel and then come back and try to weld the open areas. The welds never end up looking like one continuous weld....at least mine don't. So what I do is make a spot weld that penetrates well and pause as I move slightly, then another overlapping spot weld, and another, etc until I have an inch or so of spot welds. Move to another area and do the same thing. Seems to be much easier to keep them straight and easier to join them as you fill in the gaps. Less chance of warpage...........and don't take warpage lightly. It sneaks up on you and its a PITA you want to avoid. If I want a nice weld on thin stuff, then I go for the Tig. Try running an overlapping series of spot welds on some thin metal and see how it goes for you.

Oh, and my understanding of leaving a small gap is so that the panel has some room to expand without warping. If you are welding a patch panel in place that will be welded on all 4 sides.........I would not tack all 4 sides in place initially. I would do 1 side completely and do an adjacent side as well. That will allow the other two sides to expand and then cool without putting pressure against the unwelded sides. Then take a thin cut off grinding wheel and dress the two remaining sides to fit/OR slit the remaining 2 sides so there is a gap the thickness of the cut off wheel. Actually, do only one of the remaining sides at a time. It helps keep from putting as much heat into the panel by not welding all 4 sides in place at one time.

 

Going back to the OP,s original post. He wants to weld 18/19 gauge metal to 16 gauge metal.
He didn't prep or clean the metal properly.
OP needs to go back to the beginning and use the same gauge metal for the patch as is the parent metal.
OP needs to prep the metal properly if he has any hope to do a quality repair.

 

Practice , practice , on scrap pieces till you get the hang of it...on floors no need to butt weld really...i use a panel flanger and either rosette weld or just lay bead...

 

Update: the welder crapped out. For some reason the wire feeds but then binds up and spaghetti’s. So I need to figure that out. BUT, I got one good zap in. Much better, turned the heat up one notch and feed down a notch. If this goes well then I will prep some more scrap for testing with nice edges, clean etc. these were both on the 16 ga. Steel.

 

tip may be closing up, keep the line from the machine as straight as possible and loosen up the feed rolled a little. better to have them slip than ball the wire up. slowing the wire speed or increasing the heat may give you more penetration and moving the puddle side to side may help also

 

Practice makes a welder . I think I would flanged the floor panels , punched holes , clamped and plug welded the holes , skipping around .

 

75% of all welding problems are usually poor grounds.
Metal needs to be clean where ground clamp attaches and the ground should be as close to the work (arc) as possible.

 

Likely a problem with the liner in the weld lead, either kinked or has pulled contaminants in it, if it's kinked you will have to replace the liner and if it's dirty you should remove the wire that's inside the lead and try blowing it out with compressed air then make sure you keep the lead as straight as you can when welding!

 

Watch your heat and wire speed settings, to slow on the wire with to much heat will cause the arc to come back up to the tip and start to melt that causing it to stuff everything.
As said it could be your liner and dirty wire, especially if not used frequently the wire will develop light rust and make it stick in your liner.
Pull your liner out , blow it out with compressed air and I reckon you’ll be amazed how much dust and particles come out. All causing the wire feed to play up. Basic mig maintenance.

 

Sorry Dick, just read your comments to late.

 

As said above CHECK TIP FIRST! The tips will go bad quickly if you've been having problems with heat and feed (which you have) THEN check feed rollers to make sure they aren't dirty and gummed up.

Clean the rollers with acetone (fingernail polish remover), alcohol, paint thinner etc.

Also check your wire for small rust spots, high humidity areas and this can be a problem.

Then on to the liner inside the trigger feed cable.

One thing to try, open the side and pull the trigger, watch to see if the rollers run smoothly and the wire starts jumping, if the rollers run smooth its definitely one of the above....

...

 

I watched them roll and they were smooth until the wire gets almost to gun and bam. It will spool up at the rollers. I am planning on taking the liner out to either clean or replace. I will also clean the rollers as well.