Welding Question, Newbie Mig welder here trying to make some plug welds Options

[nathanxnathan]

I've been tig welding for the past 10 years and I think I'm alright at it, but I recently got a mig welder as I think some stuff I need to do on the car I need to go that route. I have a few questions...

So I got argon/co2 mix, I think 75/25, got some.023" wire.

First question, about plug welds, how big a hole should I drill? I saw this on the American Welding Society website

Per AWS D1.1

The minimum diameter of the hole for the plug shall be no less than the thickness of the part containing it plus 5/16(8mm) preferably rounded to the next greater odd 1/16". The maximum width shall equal the minimum width plus 1/8"(3mm) or 2-1/4 times the thickness of the member,which ever is greater.

For slotted holes it is the same as above except the length of the slot shall not exceed 10 times the thickness of the part containing it.

The minimum center to center spacing for plug welds shall be 4 times the diameter of the hole.
The minimum center to center of slot welds (traverse direction (this way II) shall be 4 times the width of the slot. Longitudinal direction (--) shall be 2 times the length of the slot.

The material I'm planning to use for repairs is 1 mm, so it's saying I need to make the holes 9 mm, which is 3/8 inch almost. —That seems really big given the size of the flange on most parts. Like it would be hard not to burn through the edge or both edges and make a mess to do that?

Other question is maybe a stupid question, but I find the torch this Hobart Handle 140 came with to be super awkward, like first of all it is gigantic coming from tig welding. Tig I always use a #7 or a #9 torch. This thing is like 2 sizes up from that equivalent it would seem. Secondly the button to weld is like a pistol — on the front/bottom of the torch, so it's really hard to weld on the bench. I have to put my elbow way up in the air to point the torch downward. I'm trying to angle it about 10º. So I get all shaky trying to do this, supporting it with my whole arm — I think my welds would be more controlled if a could weld with just my wrist, if I were able to support/rest my elbow on the table. If the button were on the top of the torch it would be more natural, to hit with my pointer finger. I guess a tig torch you can hold multiple ways, but the mig torch, I've tried holding it "the other way" and pressing the button with my thumb, but that's awkward, too. I'm not terrible if I use both hands — 1 to hold/stabilize it and 1 to press the button, but that seems dumb.

Here is a few practice welds, first pass at this. the right is me playing with voltage and feed, the leftmost is the 2nd , and then the middle last. Some of them is me trying with 2 hands, the better welds. Then the 1 hand, trying different holding positions I get off a bit. A few of them I was playing with "forging" the welds pounding them with a hammer to feel if they were harder than I'm used to as I've heard that about mig vs tig — they seem the same to me that way though.



The holes I drilled I are much smaller than 3/8, was going for something that seemed closer to what I'd want to do based on the typical size of a flange on most parts.

Maybe anyone has some insight on this?

[Superhawk996]

The material I'm planning to use for repairs is 1 mm, so it's saying I need to make the holes 9 mm, which is 3/8 inch almost. —That seems really big given the size of the flange on most parts. Like it would be hard not to burn through the edge or both edges and make a mess to do that?

Great research (IMG:style_emoticons/default/smilie_pokal.gif)

And then there is the practical side of it as you've noted.

Maybe @mb911 will chime in

I generally used 8mm - 10mm (~3/8") spot weld cutters and these became the rosettes that needed to be filled & welded later. In some rare instances of narrow flanges, I punched 1/4" holes and burned and filled them out closer to 3/8".

I TIG welded everything. Slow but it also helped keep from overheating parts and warping stuff.

Best trick I found to keep from burning though flanges is to start the weld on the thin side, where you'll tend to get a cold start. Once there is enough filler in the puddle to get good thermal transfer to both panels, I worked my way back around to the thin edge that started cold and then made sure I had good fusion there and ended the weld.

If you can back the flange with a copper backer that works great to avoid burning out that thin section but isn't always feasible.

Couldn't have TIG welded so well on car without this lovely little TIG accessory. I'm in love with it. No longer use my foot pedal -- ever! No affiliation - just love the product so yes, this is a shameless plug for them.
https://www.6061.com/tigbutton.htm

[mb911]

So a few things.

1st what the heck is a #7,#9 TIG torch? I have never heard that before in my 26 years of professional TIG welding. Are you referring to the nozzle? The nozzle sizes come in many sizes. #7 means 7/16" opening and a #9 means 9/16"

As far as the handler. The gun is pretty small. My guess is you are holding it wrong and that is not uncommon.

I do as well use a 5/16-3/8" size hole for spot welds. I prefer to do them with MIG versus TIG only because of speed in an out.

Let me know if I can help. I teach it for a living.

[era vulgaris]

I'm by no means a professional welder, but I have been MIG welding for several years now and am pretty decent at it. I've never been able to weld one-handed. I suppose I could to quickly tack, but definitely not to run a bead. My right hand holds the gun more like a golf club, and less like a pistol. My right hand pulls the trigger with my index finger, my right wrist articulates rotational movement of the gun to "push the puddle", and my left hand is used to stabilize the gun. Magnets or clamps keep the two pieces of metal from moving. Not sure if that's correct or proper, but it works for me.

[tygaboy]

3/8 holes and both hands (whenever possible) for me. Mig preferred to TIG for the same reasons as Ben @mb911 . Anything smaller than 3/8 and I found that I risked closing the hole before the "base" material was molten. Start in the middle then work the puddle around, catching the edge of the hole.
In fact, I was just doing it yesterday, helping repair a friend's BMW.
Your middle examples are the result you want - the ones where it's a nice little mound with a small crater at the finish point.
Also, MIG results in a harder weld than TIG, which is harder than Oxy/Acetylene. I'd recommend against hammering MIG welds as they can end up cracking. A nice plug weld shouldn't even need grinding, unless you need the clearance for something that ends up right on top of the weld area.
My $0.02.

[nathanxnathan]

So a few things.

1st what the heck is a #7,#9 TIG torch? I have never heard that before in my 26 years of professional TIG welding. Are you referring to the nozzle? The nozzle sizes come in many sizes. #7 means 7/16" opening and a #9 means 9/16"

As far as the handler. The gun is pretty small. My guess is you are holding it wrong and that is not uncommon.

I do as well use a 5/16-3/8" size hole for spot welds. I prefer to do them with MIG versus TIG only because of speed in an out.

Let me know if I can help. I teach it for a living.

My bad, memory not serving me well there. I should have said WP17 and WP9 — somehow was thinking the smaller was a 7, but it's 17.

Here's a comparison of scale with the mig torch


It seems suited to hold like this
(IMG:http://www.914world.com/bbs2/uploads_offsite/cdn.thefabricator.com-21899-1656702819.1.jpg)

but only if you are welding on a vertical surface — when I try to weld on a table, which is most comfortable when I tig weld, I feel like I have to put my elbow up in the air to postion the torch at a 10º angle from the part which I've read is ideal.

Maybe there is a better way to hold it or maybe I should position the part at an angle. Maybe it's just not as versatile, mig welding, as I'm used to.

5/16 hole I think would work — I'm gearing up to do a repair on the car, and I don't want to do it wrong. It seems silly but I often have found on introspection that I will put something off if I don't know exactly how to do it. I'm trying to overcome and get to it, not let this project languish, so I guess ask some dumb-seeming questions.

[Montreal914]

Thank you for these tips! (IMG:style_emoticons/default/smile.gif)

[nathanxnathan]

I'm by no means a professional welder, but I have been MIG welding for several years now and am pretty decent at it. I've never been able to weld one-handed. I suppose I could to quickly tack, but definitely not to run a bead. My right hand holds the gun more like a golf club, and less like a pistol. My right hand pulls the trigger with my index finger, my right wrist articulates rotational movement of the gun to "push the puddle", and my left hand is used to stabilize the gun. Magnets or clamps keep the two pieces of metal from moving. Not sure if that's correct or proper, but it works for me.

Ah ok, so 2 hands is normal — really seemed like it was kind of wrong. I'm new at it, like every time I try to weld, I still am looking down/feeling for the pedal. (IMG:style_emoticons/default/biggrin.gif)

[nathanxnathan]

3/8 holes and both hands (whenever possible) for me. Mig preferred to TIG for the same reasons as Ben @mb911 . Anything smaller than 3/8 and I found that I risked closing the hole before the "base" material was molten. Start in the middle then work the puddle around, catching the edge of the hole.
In fact, I was just doing it yesterday, helping repair a friend's BMW.
Your middle examples are the result you want - the ones where it's a nice little mound with a small crater at the finish point.
Also, MIG results in a harder weld than TIG, which is harder than Oxy/Acetylene. I'd recommend against hammering MIG welds as they can end up cracking. A nice plug weld shouldn't even need grinding, unless you need the clearance for something that ends up right on top of the weld area.
My $0.02.

Nice, thanks for the tips and info. So I think I'm moving in the right direction.. a bit more practice and I think I'll be ready to actually weld on the car (IMG:style_emoticons/default/welder.gif)

[nathanxnathan]

The material I'm planning to use for repairs is 1 mm, so it's saying I need to make the holes 9 mm, which is 3/8 inch almost. —That seems really big given the size of the flange on most parts. Like it would be hard not to burn through the edge or both edges and make a mess to do that?

Great research (IMG:style_emoticons/default/smilie_pokal.gif)

And then there is the practical side of it as you've noted.

Maybe @mb911 will chime in

I generally used 8mm - 10mm (~3/8") spot weld cutters and these became the rosettes that needed to be filled & welded later. In some rare instances of narrow flanges, I punched 1/4" holes and burned and filled them out closer to 3/8".

I TIG welded everything. Slow but it also helped keep from overheating parts and warping stuff.

Best trick I found to keep from burning though flanges is to start the weld on the thin side, where you'll tend to get a cold start. Once there is enough filler in the puddle to get good thermal transfer to both panels, I worked my way back around to the thin edge that started cold and then made sure I had good fusion there and ended the weld.

If you can back the flange with a copper backer that works great to avoid burning out that thin section but isn't always feasible.

Couldn't have TIG welded so well on car without this lovely little TIG accessory. I'm in love with it. No longer use my foot pedal -- ever! No affiliation - just love the product so yes, this is a shameless plug for them.
https://www.6061.com/tigbutton.htm

Interesting to start on the thin side. I will give it a try. I was starting at the middle and circling out, then trying to come back in so the finish would be centered.

It's so off and on, mig welding, like with tig I think it's a sign you're doing it wrong to have those little volcano-looking bits at the finish. It means you are coming up off the pedal too fast I read. If you taper off the pedal to finish, the weld comes out smoother. I guess some tigs have just a button so that's on and off as well.

I've got a thumb control like this, but I don't use it that much

(IMG:http://www.914world.com/bbs2/uploads_offsite/s.yimg.com-21899-1656703767.1.jpg)

kind of finicky the wheel through the gloves. I need to practice with it more.

[NARP74]

So you're saying I should not let the kids across the street plug some holes in my trunk for me? They do not have this level of understanding or experience.

[930cabman]

3/8 holes and both hands (whenever possible) for me. Mig preferred to TIG for the same reasons as Ben @mb911 . Anything smaller than 3/8 and I found that I risked closing the hole before the "base" material was molten. Start in the middle then work the puddle around, catching the edge of the hole.
In fact, I was just doing it yesterday, helping repair a friend's BMW.
Your middle examples are the result you want - the ones where it's a nice little mound with a small crater at the finish point.
Also, MIG results in a harder weld than TIG, which is harder than Oxy/Acetylene. I'd recommend against hammering MIG welds as they can end up cracking. A nice plug weld shouldn't even need grinding, unless you need the clearance for something that ends up right on top of the weld area.
My $0.02.

Nice, thanks for the tips and info. So I think I'm moving in the right direction.. a bit more practice and I think I'll be ready to actually weld on the car (IMG:style_emoticons/default/welder.gif)

I have found with welding (and most anything) practice makes perfect. Good call to complete a bunch of samples prior to the actual work and best of luck with your project

[mb911]

So a few things.

1st what the heck is a #7,#9 TIG torch? I have never heard that before in my 26 years of professional TIG welding. Are you referring to the nozzle? The nozzle sizes come in many sizes. #7 means 7/16" opening and a #9 means 9/16"

As far as the handler. The gun is pretty small. My guess is you are holding it wrong and that is not uncommon.

I do as well use a 5/16-3/8" size hole for spot welds. I prefer to do them with MIG versus TIG only because of speed in an out.

Let me know if I can help. I teach it for a living.

My bad, memory not serving me well there. I should have said WP17 and WP9 — somehow was thinking the smaller was a 7, but it's 17.

Here's a comparison of scale with the mig torch


It seems suited to hold like this
(IMG:http://www.914world.com/bbs2/uploads_offsite/cdn.thefabricator.com-21899-1656702819.1.jpg)

but only if you are welding on a vertical surface — when I try to weld on a table, which is most comfortable when I tig weld, I feel like I have to put my elbow up in the air to postion the torch at a 10º angle from the part which I've read is ideal.

Maybe there is a better way to hold it or maybe I should position the part at an angle. Maybe it's just not as versatile, mig welding, as I'm used to.

5/16 hole I think would work — I'm gearing up to do a repair on the car, and I don't want to do it wrong. It seems silly but I often have found on introspection that I will put something off if I don't know exactly how to do it. I'm trying to overcome and get to it, not let this project languish, so I guess ask some dumb-seeming questions.

You are holding it correctly if held like in the picture. You want to chicken wing it to hold correctly for both work and travel angles. Also not technically flat position is at an angle in the welding world but I am not going to go down that path right now. I really should do a video for all you guys.

[bbrock]

I'm not a great welder so use all the help I can get. I bought one of thes and found it very helpful for a lot of flange plug welds. I ground the top edge of the copper pad flat to get better clamping on short flanges

(IMG:http://www.914world.com/bbs2/uploads_offsite/m.media-amazon.com-20845-1656735250.1.jpg)
https://www.amazon.com/Eastwood-Plugweld-Pl...s/dp/B07PML9GF6

[rick_cv]

I also like to start in the center and circle out. I try to run wire speed a bit slower and run voltage a bit hotter so that I don't fill up the plug weld with a giant cold bead. And clamp both sides of the hole somehow. Nothing sucks more than having the top layer pull away from the bottom and left with a gap between the two layers. I am also comfortable with a 1/4 or at most 5/16 hole when running a hotter setting. Remember you are just replicating a spot weld which is pretty small in surface area.