how thick do you weld with your wire feed / mig?

[gauthier]

Thats the thing with mig welding,it can look real good[didn't click on pictures so no judgement on them],but ..kinda like a girl with a whole lot of make up on.
If you got a good looking stick weld,its got a much better chance of being good all the way through than a good looking mig weld. Thats why in fab shops and such where they use mig alot,they have welding procedures,that tell everybody what amps volts travel speed,cleaning,preheat,max thickness you can lay down with single pass to do when welding a joint,than its up to the welder to pass a test using those perameters.[Mig is alot easier to make a good looking weld with at lower amps and volts],turn it up,it gets a lot harder.And it really gets hard when you turn it up and try and weld out of flat postion,takes alot of skill.
Thats why in good fab shops,where they are working to a code and specs,and not just back yard welding,you do see good mig welds,[like somebody said about car frames],they do it to get the results they need to have a quality weld,they have proven it by qualifying welding procedures,and than writing a welding spec off that procedure to do production welding that will meet requirements.Than they tests the welders to make sure they can weld to that procedure and in what postion he will be welding in[course car frames and such like that,they use robots,but even those robots gotta pass the tests.
Thats why I say you can make a good solid mig weld,its just the chances are greater for mistakes on thicker stuff,you got to know what you're doing to do it.
Unless your after production,or welding mainly on sheet metal[which most back yard welders airn't],than buy a stick machine,heck,buy a motor generator stick machine and you can weld anywhere plus you got a generator for generator stuff.Migs are much more complicated than stick too,much more stuff to keep clean,wear out,get gomed up,break,etc.

 

[lostcause]

Well,

Cold lap is sort of like a "muffin top" where the weld spills over on the top of the metal, but isn't properly tapered to the joint edge and isn't properly fused at the toes, even though it looks "nice". This is typically due to inadequate heat and trying to make a weld wider than it should be. Even though you have heat lines, it isn't a good indicator of a properly fused weld, only tells you where the heat was directed and if it was properly centered in the middle of the weld. If you'll notice, you don't start getting the heat lines until after the edge, toward the middle of the weld on both sides. This means the heat was lagging behind the weld. This also means that proper penetration was not being achieved. The heat lines would follow the weld seam more closely if near 100% penetration was achieved.

ok, i'm mostly with ya here. i understand the cold lap issue, just don't have the experience to visually identify it after the fact. one last question (for now): when you talked about near 100% penetration, were you talking about complete penetration over the thickness of the material, or are you just talking about enough penetration to be safe in knowing that the weld bead just won't fall off the base metal?

 

[Mark @ Everlast]

If you are relying upon any metal to hold weight or support weight, it is no stronger than the weld that holds it. If you are not getting complete joint penetration all the way through, then you are wasting the metal that you are using if it doesn't go all the way through or support an area wide enough in the case of a fillet weld. But in the type joint you presented, it is useless unless the weld is penetrated all the way through the metal or it can be welded from the backside so that both welds meet. You cannot claim that it will weld 1/4" or greater metal in a single pass if it will not fully penetrate that amount in one pass. Of course, as was mentioned earlier, smaller multipass welds are typically preferred and are of higher quality.

The weld presented doesn't appear to have much more than 1/8"-3/16" penetration at best from my estimates, leaving 1/4" of the metal unfused.

In other words, this weld would not be safe for the thickness of metal it is holding. No it probably wouldn't fall apart from handling or even completely assembled, but I'd bet if you put it in a press and put pressure at the top of the joint it would pop right apart.

 

[Bill_C]

As I've said before, I think there are two extreme schools of thought when it comes to the 110 volt wire-feeds. There's the first extreme: a beginner who's never welded in their life, who thinks they can buy a 110 volt wire-feed from the Chinese import store and immediately weld a trailer hitch together. The opposite extreme: those who think 110 volt wire-feeds are mere toys, incapable of ever doing any "real" welding.

Both extremes are wrong. The 110 volt machines do have definite limitations, realistically they can supply around 100 amps at 17 volts, give or take. Some of the Chinese imports weren't even DC!! Will I weld a 3/8 inch thick trailer hitch--what I would consider a critical weld--with a 110 volt wire-feed, for example? No way!

However, if you want a portable machine that can weld outdoors (which is ideal for flux-core), and you can accept the material thickness limitations and duty cycle limits, the 110 volt machines are quite useful. Welding a 1/8 inch thick mower deck? No problem with the 110 volt machine. 3/16" mailbox bracket? No problem, run an extension cord outside and use flux-core. Exhaust tubing? Go with thinner solid wire and add 85/15 gas and it'd work great.

My travel trailer frame is 1/8 inch thick sheet metal (I know, its a crappy Lippert frame). One of the spring hangers ripped off the frame. After doing the "critical" work with the Hobart 175 (220 volt MIG with 100% CO2) I used my 110 volt Lincoln Weld-Pak 100 with flux-core to finish up. Still had more than enough oomph to burn through if I didn't watch my work carefully (easier said than done, lying on your back with the arc inches above your face). There's no way I could've welded the 1/8 inch thick stuff with stick (I'm not that good, I know its possible).

Different people have different needs, different levels of experience, and different expectations. The "best" welder for one person might be a big gas-driven Pipeliner. Another person may find a small TIG "best" for their needs. A household/hobbyist may find a 110 volt wire-feed "best" for their needs. Or if someone has many various needs, they get several welders, a mechanic has more than one size wrench in his toolbox!

For a beginner, taking a welding class will expose them to various processes and help them decide what their first welder should be. Then their second...then their third...

 

[gauthier]

Looked at the pictures,looked like a corner joint? Looked like flux core,looked like you was burning hot,can't tell much about third picture,kinda confusing to me.
This not concerning those pictures,To me cold lap is on face or root of weld,its over lap on toe,convex bead,edge of weld,that you can't see with eye ball really,got to grind it down and see where it is fused at and where its not,a dye penatrant check would help the eye balls in this. Lack of fusion is in weld or on root edge,its where the weld did not fuse to base metal weld jointsides,or between passes on a multi pass weld,something resembling what I said anyways,some may call it one or other,but both are bad,its about the same as a crack[or worse],it can spread grow like a crack,and if its on inside,you can't see it,sometimes xray won't pick it up even.
Thats what mig[short circuiting mig] is know for,thats why its got a bad rep.
You can have this with other process but mig is the best known for it.
There are several reasons for cold lap and lack of fusion,the mig helps in most of these,just the way the wire melts,it short circuits,it hits metal melts and wire burns into,than it does it again and again,thats the sound you hear with a mig,than the wire is very small,small puddle,and easy to get outside puddle and not know it,than you get lack of,,you got too have clean metal to help this,the mill scale melts at higher temp than the steel,so that helps if its not clean,you can't just rely on it burning/tieing into edge of weld groove,you got to manipulate your gun in order to do this. Plus like I said,its alot easier to use if its not running hot,so,many turn it down,and make pretty beads!
Good for what it was designed for,single pass,thin stuff,and it works best,down hill.
But to me that weld in those pictures just looked typical for flat flux core.

 

[lostcause]

If you are relying upon any metal to hold weight or support weight, it is no stronger than the weld that holds it. If you are not getting complete joint penetration all the way through, then you are wasting the metal that you are using if it doesn't go all the way through or support an area wide enough in the case of a fillet weld. But in the type joint you presented, it is useless unless the weld is penetrated all the way through the metal or it can be welded from the backside so that both welds meet. You cannot claim that it will weld 1/4" or greater metal in a single pass if it will not fully penetrate that amount in one pass. Of course, as was mentioned earlier, smaller multipass welds are typically preferred and are of higher quality.

The weld presented doesn't appear to have much more than 1/8"-3/16" penetration at best from my estimates, leaving 1/4" of the metal unfused.

In other words, this weld would not be safe for the thickness of metal it is holding. No it probably wouldn't fall apart from handling or even completely assembled, but I'd bet if you put it in a press and put pressure at the top of the joint it would pop right apart.

for any welding issues, i'll bow to your knowledge and experience, but this is a case where i can't totally agree with you. reading this has actually enlightened me a little to the thought process of many people here though. i get the impression that many here don't consider a weld effective unless it has 100% penetration.

to me, this is something i would never even consider. i guess it comes from my background. i'm used to seeing 3/4" steel welded with a single 1/4" fillet on each side. there's absolutely nowhere near complete penetration there. for longer applications, a minimum sized intermittent fillet, maybe a 3/16" fillet with a 3" on 12" intermittent pattern on 1/2" material is often all that is called for.

quite often the thickness of steel used has nothing to do with how much load needs to be transferred through a weld. the material size and thickness could be a result of shear stress, bending stress, deflection limiting, bolt bearing, block tearout, or any other number of conditions. a weld much smaller than the material may be well more than is needed.

i'd never sit down and do calculations for any of these things though. some i could sit down and rattle out, but others i wouldn't have a clue where to start. in pretty much every case, it's not a matter of inventing the wheel. someone has already done something similar and we have the benefit of seeing how it was previously done to base our ideas on.

again, nowhere near the topic, but i think i already have a large enough lack of answers to answer my question. i do appreciate all the replies though. many of you are much more qualified to answer any questions on welding, but i think this may be more of a fabrication issue than a welding issue. the welding issues are total tangents to the question.

 

[yomax4]

Honestly, On on 1/4" material. Brazing Rod is as effective as a 115v Mig unit single pass.. There are a few 115v Stick units that will perform on 1/4. Don't get me wrong, I love the small machines, I sell them..I also sell 600 amp units as well as Twin Pulse Synergic systems. This has been a complicated thread to say the least. I agree that in an everyday non production world. You do not need 100% penetration to get satisfactory results. People use Bolts, No penitration there.

 

[lostcause]

Honestly, On on 1/4" material. Brazing Rod is as effective as a 115v Mig unit single pass.. There are a few 115v Stick units that will perform on 1/4. Don't get me wrong, I love the small machines, I sell them..I also sell 600 amp units as well as Twin Pulse Synergic systems. This has been a complicated thread to say the least. I agree that in an everyday non production world. You do not need 100% penetration to get satisfactory results. People use Bolts, No penitration there.

****, i wonder how people are stuck on 120v welders, because since the first post, i've been asking about 200a+ welders. i said i currently have a 120v welder, but that's the end of it. all my questions are related to the use of (or actually, lack of use of) 200a+ welders, so we're talking 240v, not 120v.

i actually think the problem is that it is being looked at by welders without the thought of production. you don't do full penetration unless you absolutely have to, and then you try to get out of it by suggesting an alternate method and hoping to get it approved instead. everyone here seems to revolve around complete penetration for all welds, and i guess it just doesn't compute to me. tbn members are building small implements and trailers, not building pressure vessels for reactors. if you look at any implement you own you are guaranteed to see a lot of intermittent welds and very few welds that are complete penetration.

from my point of view, in a production world, you absolutely do not want to do 100% penetration. if you want to do it cause you like it, that's fine. nobody will dispute the strength of your stuff, but go to work for a structural fabricator and tell them all your welds are going to be 100% penetration and you feel they should be done with tig and see what they say.

the only point to my question was simple, but probably less than half a dozen people even seemed to understand it. i'm giving you a perfect condition in the shop to weld two pieces of 1/4" material together. you don't need to transfer the weight of the world, it just has to be a solid weld. can be laid in any position, no standing on your head here. everything is perfect. it's just that i've seen posts where people say they own a 250a wire feeder, but very few ever seem to use it. if the defer to stick for welding anything of this size or larger. i just wonder what they use their expensive wire feeder for.

 

[yomax4]

I actually do see your point here. If I / You have a 150+ Amp Mig Welder,
I / You would " almost always " run it at over 19 volts.
( which is about what a 115 Mig puts out ) Welding 1/8" + ... Or put in .030 or .023 wire and dial it down to do sheet metal and up to 1/8". If you are ok with that then all is well. But...At 150+ amps on mig, You can rest assured you will have bird pooped your pieces together good enough to not have to re-do or pay someone else to fix your blobs or get sued for some accident. There really is a reason that there are 230v Welders.

 

[lostcause]

I actually do see your point here. If I / You have a 150+ Amp Mig Welder,
I / You would " almost always " run it at over 19 volts.
( which is about what a 115 Mig puts out ) Welding 1/8" + ... Or put in .030 or .023 wire and dial it down to do sheet metal and up to 1/8". If you are ok with that then all is well. But...At 150+ amps on mig, You can rest assured you will have bird pooped your pieces together good enough to not have to re-do or pay someone else to fix your blobs or get sued for some accident. There really is a reason that there are 230v Welders.

heh,

maybe it didn't read that way, but yes, i know there is a reason. my initial question was about 90% rhetorical. i just posed the question because i see all these people saying they would stick weld a certain simple condition, but those same people say they own a wire feed, and it is invariably a 240v. i was mostly wondering why THEY never used the wire feed. i didn't expect a flurry of great reasons, but i thought there might be a good point or two. the question has always been 200a wire feed vs 200a stick, never 240v vs 120v.

i got a little frustrated when tig replies started hitting, because in all honesty, tig has got to be the worst possible choice for the conditions i described. tig has its place, but i don't think you will find any fab shops using tig to manufacture entire trailers and implements.