[Braehill]

Jawon,
Take an 1/8" (3mm)grinding wheel and cut slots about an inch long (25mm) through the top layer and run a bead just hot enough that it doesn't melt through both layers. I used to do it on body tin all the time, I've done it on 16 gauge also.

Len

[Jawon]

Ah, so "slot welding". Thanks!

Does this imply that stick welders are not good for plug welding?

If the slot is 1/8" wide, should I be using the smaller 1/16" rod? Seems like you may not be able to get up close into the slot with a 1/8" rod.

Is an inch long SLOT weld on sheet metal MUCH LESS prone to burn thru than an inch long BUTT weld? On butt welds, I've been doing very short sections at a time (like 1/2") so as not to burn thru or warp. But I'm guessing slot welds will be much more forgiving so that going an inch at a time will be ok.

[Braehill]

Jawon,
I was referring to stick welding, so yes stick welders are fine for plug (slot) welding. You can make your slots shorter if you can, a 4 1/2" grinder can't make a slot much shorter than an inch, you could use a 3" muffler cutter to make shorter ones.

You don't have to get down in the slot if you run the heat as high as you can without melting the backside, the cut edges will melt in faster.

Len

[noddybrian]

Agree with Len that a slot is easier as you can use rod angle to help with slag but on that light a gauge I'd keep it fairly short as burn through won't take long - here's a strange thing though - after having many " discussions " on suitability of 6013 for various things I actually think it's not the rod of choice - I would say 6010 or 11 would be far better as they will push the slag out - just need a little practice with amps / time so as not to punch right through - I reckon you could keep with holes not slots using those rods.

[Jawon]

Thanks! I gave it a quick try. I see the light! I used a 1/16" rod and there was way too little metal filling the slot so I will play around with different combos of gap width and rod size.

As for trying 6011, I thought it was a deeper penetrator than 6013, so it wouldn't be good for sheet metal. I will see if I can get these slot welds to work with the 6013 first.

Thanks for the info. If there are other options/tips for doing these plug/slot welds, please do share.

[Otto Nobedder]

In your application, I would stay with the 6013, and drag the rod a good 15* so the slag is pushed out behind your weld.

Slot-welding is much easier than plug-welding on thin materials.

Steve S

[Jawon]

Thought of another question. This is for the car body and most of the welding would be on panels that are perpendicular to the ground (and the slot would run left to right). I've been practicing butt welds by pointing the rod UPWARDS as I move across, but what should the rod position be for slot welds?

If pointing up, seems like the heat would be focused on the top edge of the slot. Should I just run the rod parallel to the slot (and the ground) or is gravity going to mess with it?

[Otto Nobedder]

Gravity does have an effect. In a 2G position, I will (while still dragging that 15*) lean about 15-20* "up" with the weld.

That first eighth-inch or so of the weld will want to "sag" due to gravity. Pointing the rod up at a slight angle will allow arc-force to counteract this a bit.

If this does not work for you, there is also a "push" method that can work. There's many ways to skin this cat. It all depends on what works for YOU.

Steve S

[Jawon]

Been practicing slot welds and for the life of me cannot get this to work. The best luck seems to be when I punch 2 holes adjacent to each other to create a "slot" (as opposed to grinding a line). Still, the majority of the time the slag ends up under the top sheet.

Thanks for the prior tips... any others? I'm using 1/16 6013 at about 30amps DCEN on 18 gauge and the slots are 4.5mm x 9mm. I've played with different rod angles, rod speed, arc length, slot sizes, starting/stopping at different points, even long arcing, etc. What's the trick?!!!

If all else fails, I'm thinking of using lap joints. Is there any reason why a lap joint shouldn't be done in areas where spot welds are typical? For instance along the bottom flange of a car rocker.

[Boomer63]

Keep your arc tight. Long arc will increase you amps on stick. Personally, I am not a fan of 6013 and prefer the 6011 – but I am not going to tell you to switch rod. 6010 and 6011 “fast freeze” rod. Use that aspect of the rod to help you in what you are doing! Hit a tight arc, whip and pause, repeat once or twice, then come out of the weld and let it cool. With the stick process on that thin material, you aren’t going to ‘build’ a puddle, drag it along and weld like you would with thicker material. With the 18 gauge you are working with, I would almost suggest just making a series of tacks; you might not be able to run a bead. By the time you see a puddle form, you have burned through.

Good luck! It is a difficult job you are trying to do! I have done them, but not in about … thirty or so years … or something like that. After a while, the span of years doesn’t mean much – it is all just “a lot”!