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Mcgyver
12-07-2008, 10:30 AM
I finally picked up a nice little 220V mig welder.

whats making me crazy though is the beads. seems no matter what i do a get a big bead proud of the work. I started with Lincolns recommended settings and varied it a bit but not luck. I was in a plant the other day with a robotic mig welder and saw the same thing....most of a semi circle bead sitting proud of the 11 gauge they'd welding.....yet I'm sure I've seen nice flat scallop mig beads before :confused: :confused:

I had to weld some 1" sq 1/16 tubing the other day. @#$@# the Mig welding; I grabbed the O/A rig....at least with it I can get a good weld that is pretty flat and doesn't take a half a day of messy grinding. Disadvantage though is more heat is pumped into the work so i worry about warp and it takes longer...so I'd rather Mig if i can figure it out

is this just the nature of the beast, or what should look to to get a better result? I'm new at the Mig welding so hopefully its something simple/common/easy to fix that I'm doing wrong

torker
12-07-2008, 11:21 AM
If your beads are too ropey...you have too much wire feed for the heat setting...or you are traveling too slow.
If you are pulling the gun...the beads also tend to rope up.
Flatter beads are easier when you push the gun..
Ropey beads (or poor wetting in the edges) can also be caused by welding on cold metal with mickey wire.
Make a pass on cold metal...then run a bead that half overlaps the first and you'll see what i mean. The last bead should always be flatter. It's the heat that helps it flow out.
Also...too much wire stickout will cause ropey welds..

macona
12-07-2008, 06:48 PM
Also check your polarity. If the machine was used for flux core it may still be set for that. It will still weld but you will never find a good wire speed/voltage combination to make it run right.

Or are you even running hard wire and gas?

What machine?

Also what size of wire are you running? On what thickness of metal?

Errol
12-10-2008, 04:12 PM
Mcgyver, you are exactly where I was some years ago. I just bought a mig welder and experienced the exact same problems.

So I got a millwright friend to come over to give me some pointers. To get as flat as possible surface, here are a couple of things I learned.

Chamfer all your joint edges with grinder prior to welding. Lots of angle.

When welding tubing, like 1" sq x 1/16, and you need a "flat" surface, then leave a bit of a gap between the pieces, then turn up the heat as if you were going to weld 1/8. Then use the contactor in a "stitching" fashion, short burst, move, short burst move and so on... almost like TIG. With some practice, you will get the hang of it.

On verticals, come "down", not up.

And like Torker says, push, rather than pull.

torker
12-10-2008, 07:27 PM
Errol...you gotta be really careful "burping" a mickey wire weld.
As long as you have the heat up and are working with light material..it will work.
However...If you are working thicker steel...the chances for cold lap happens everytime you pull the trigger.
Also...mickey wire downhand is ONLY ever used with body work on automobiles.
There is almost no penetration with it.
Even with .045 dualshield running at 28 volts...your still walking on very thin ice when it comes to downhand welds.
Any fab shop I've ever worked in would fire you if you run downhand on anything but chuteing.

ahidley
12-11-2008, 09:00 AM
Torker whats "mickey wire."

camdigger
12-11-2008, 11:34 AM
Isn't Mickey wire that stuff they use in them Mickey Mouse squirt gun welders???:D


Kidding (mostly)

torker
12-11-2008, 04:34 PM
Isn't Mickey wire that stuff they use in them Mickey Mouse squirt gun welders???:D


Kidding (mostly)
Sorry..."Mickey Wire"....that's weldor slang for hard wire. Called it that for so long I can't even remember what it's really called. :D
Russ

camdigger
12-11-2008, 04:47 PM
'mig hard wire' aka 'solid core mig wire' aka 'Mickey wire'?

Errol
12-12-2008, 08:02 PM
Sorry Mcgyver, wrong info for you. What I relayed to you worked for me to date, but I had no idea these suggestions were ill advised.

Torker, thank you for the additional info. It is a blessing to interact on a forum such as this one to learn and to improve one's skills. And it's also a blessing to have someone so knowledgeable who is willing to take the time to respond and help those of us who can benefit.

Fortunately I can't get fired, because I'm retired, but I can certainly try to change my bad habits. Incidentally, I never "burp" anything over 1/16. If the joint is critical I'll reach for the TIG or O/A.

Also I'll pass your observations back to the fellow that initially gave them to me.

torker
12-12-2008, 11:39 PM
Errol...I said be carefull with "burping"..I didn't say don't do it...hell, I do it all the time.
That method of welding isn't allowed under ANY welding procedure...but in the "real" world it is used a lot.
I got stung bad on that once.
About 8 or 9 years ago I took an autobody course for 8 months to learn how to do it right.
They handed me the welding part of the course because I had far more credentials than the instructor did.
Sly bugger got me tho...
I had welded in a panel of 20 gua with one of their crap welders.
After it was done he bet me i had holes in the 3 foot long seam. I said "No way".
I wire wheeled it to show him...it was a nice clean weld seam.
He hollered over to one of the other guys and asked him to sandblast my weld seam.
Geezuz...after it was blasted....there where 4 good sized holes in the seam.
All from cold lap...right at the start of the welds....where the light duty welder couldn't dig hard enough to get a clean restart.

Errol
12-18-2008, 12:15 PM
Torker, your experience with welding and explanation of "cold lap" makes me feel better about one of my failed projects.

Some years ago I had just fabricated a fuel tank for my bulldozer out of light gauge steel. I was pretty proud of it. I even machined a spigot with thread to accomodate the old gas cap and welded it on. The tank passed the water leak test, so I bolted it on.

After a few months, leaks developed. Then more and more leaks developing as time went on. The best I could see was that the leaks were right at the "cold laps". Just like you described.

A professional welder friend of mine, said I should have always snipped the wire clean every time before pulling the trigger. And that would have eliminated the problem.

Snipping the wire doesn't seem to make any visible difference to me. Does a fresh cut wire help with the cold lap problem do you think?

Bob Ford
12-18-2008, 04:41 PM
Unless the end is really ugly there is no need to snip. DO NOT start the next weld at the end of previous weld. Start 1/4- 3/8 inch into new joint heat up rod and then move back to old weld then continue welding. This eliminates cold joints.

Bob

torker
12-18-2008, 08:22 PM
Actually some migs do not start all that well. Snipping the wire will help.
I rarely bother doing that with my 255 machine but often do it with my lil' 135.
As Bob mentioned...you should always start back on the bead a bit.
When using hard wire at lower volts...you should even scrape the little silica islands off the bead if any appear where you want to restart.
These have caused many a weldor to fail a hard wire test. They are really hard to melt through in that short instance of restart. I always have a sharpened screwdriver near and pick at the islands till they flake off.
When I do tanks I grind a little dish where I want to start the next stitch.
It provides a clean place to restart and makes a nicer looking bead overall as you have no "lumps".
I've built about 200 or more tanks....one little wiggle can cause a leak.
I take lots of little precautions like that to minimize any leaks.

camdigger
12-18-2008, 10:14 PM
Torker

Does backstep welding help eliminate cold lap?

Cam

Bob Ford
12-18-2008, 11:43 PM
I would like to make something clear about welding. I have passed a lot of certification tests for structural welding, But it was only needed for my electrical trade. I was a construction electrician not a welder.
Torker on the other hand is a professional welder. Listen and think about his welding tips. He easily has ten times the experience that I have.
Bob

torker
12-19-2008, 12:54 AM
Hey Bob..I learn something new every day...lots of times right here...sometimes from people who have never had any formal training.
I never take anything as gossipal...until I know it works for myself. And I do a lot of things that are outside the box.
Cam...back stepping is mainly meant for controlling weld distortion.
If you can lay the beads down fast enough...it could help. You'd be welding back into a hot bead.
However..the idea there is to let the welds cool as you go so that would rule that out basically.
But then...you'd be starting out on cold metal for each start. Cold start = cold lap. Clean joint prep...proper machine settings/electrode angle...preheat and proper technique should make cold lap a non issue.

Bob Ford
12-19-2008, 10:17 AM
Russ I have no problem with what I said. You are far more experienced with welding and most important you can explain in terms people can understand. I learned a valuable lesson early in my electrical apprenticeship. I had installed and was ready to test a big D C controller for a printing press. Basically changed 480 3 phase to D C. Big sign in NEW panel said ALL CONTROL CIRCUITS 208 ac terminals 7-8 on strip B. Removed said wires off terminal strip so that I could safely touch control circuit wiring. Reach in and touched control circuit. Landed flat on A$$ about 6 feet away. Slight burn on little finger. Used a meter to check panel. Control circuit dead. Checked part of control circuit I had touched 480 v D C
Lesson learned do not believe all you read. You are responsible for your own safety.
Even though I am retired I try to learn at least one new thing each day.
Bob

Mcgyver
02-10-2009, 06:56 AM
i forget to get back to you guys, ended up figuring it out, mostly. as well as the controls, it made a difference was when i went on the .030 wire i bought vs the .025 that came with it....as was pointed out, just needed more heat

Made kind of a shop wall unit, about 14' of bench, shelves below and horizontal stock racks above, consumed like 12 20' lengths of 1" sq tube. made it as one big gangly assembly :D....by the time i was done, lots of practice and the welds are looking good. Still, with gas i don't need to grind, otoh man the metal glue gun is fast!

torker
02-10-2009, 07:02 AM
Glad to hear that's working for you.
Sounds like you still have a bit of a problem if you have to grind.

Mcgyver
02-10-2009, 08:11 AM
yeah i should have taken pics to showyou the results, but its dirty work so i don't like to have the camera out there during and sometimes you just get ploughing through and dont' want to stop.....next time :)

bobhdus
02-10-2009, 12:32 PM
I have read a lot of good stuff here. I want to really thank you guys for such great advice. Something I personally have found when doing production welding to consider for anyone that experiences wire problems or bead problems is that the wire may jump around on the weld causing uneven distribution of the heat/ puddle. This can happen on small rolls of wire due to unstable cast or helix when they rolled the wire or if using an oversized (from wear) tip. At work we change the tips each shift and sometimes 2-3 times a shift. If you have never used it you can get this stuff called Solar Flux. Its mostly used for Tig to weld without purging but makes a good backer for mig as well. You just mix it with Acetone or (HEET). It protect the back side of the weld and it allows you to add more heat with out the weld falling out on you and you can get flatter welds. Use a mild acid solution to remove. I use it all the time welding SS tubing. Thanks guys.

GKman
02-11-2009, 09:37 AM
My thinking is, if the setup and technique are doing a good job melting both pieces at a reasonable penetration then the only thing left to do is provide room for that metal that you don't want lying on top by leaving a gap in the joint or v notching.

Your comments?

torker
02-11-2009, 10:23 AM
My thinking is, if the setup and technique are doing a good job melting both pieces at a reasonable penetration then the only thing left to do is provide room for that metal that you don't want lying on top by leaving a gap in the joint or v notching.

Your comments?
Yup...that works.
Most people don't run their migs hot enough...that causes a lot of ropey bead problems. I run all my migs very hot.
Cuts down on cold lap and flattens out the beads.

loose nut
02-11-2009, 11:49 PM
Weld beading up can have a lot to do with set up and the way you are welding. Welding on the flat can make the bead mound up if your not hot enough like Torker said. If you are just welding some heavy tubing with fillet welds then leaving a small gap between the pieces will help flatten the bead.

Where I work we do a lot of MIG pipe welding by rolling it in positioners using the down hand method, by down hand I mean about 1 o'clock on the pipe not vertically down, with open roots, 37 deg bevel (standard) 5/32" gap (3/16" or more on large pipe) with no land and running HOT.

On 3 or 4" Std. pipe keeping the bead high in the bevel the puddle flows down through the gap and fusses into the root, filling the bevel and forming the root bead in one pass, a second pass will form the cap. If the pipe is heavier I MIG the root and fill and cap with stick. This is because the equipment we use is of older design and doesn't like being adjusted very much, making it easy to get cold lap between the pass (which probably won't show up on an X-ray unless the shot is taken a just the right angle), this is why we have to do a bend test to re-qualify our MIG tickets every year instead of just X-raying the weld tests, cold lap will pop out on a bend test. It's just easier for us to finish with stick and then there isn't any worry about cold lap.

I always stop and grind out any starts before running over them when finishing a pass, there can be cold lap any time you start a MIG bead even if it looks good. A little bit of precaution can prevent a lot of rework.

If you are welding MIG (short) in multiple passes it likes to be laided down in thin layers, putting down to much in a single pass can leave you with cold lap also.

Industry frequently uses flux core or Spray MIG procedures now instead of the Short circuit method (mickey wire, fine wire, micro wire whatever you want to call it), it runs much hotter and burns in with good fusion and pretty much eliminated the cold lap problem if used right, but they can have problems of there own, nothings perfect.

Most of all it's just practice, practice, practice.

JRouche
02-12-2009, 02:32 AM
Yup...that works.
Most people don't run their migs hot enough...that causes a lot of ropey bead problems. I run all my migs very hot.
Cuts down on cold lap and flattens out the beads.

LOL.. Yup. And that IS it. HEAT!! Gotta have it. Most of the time I watch a friend weld, just hobby guys like myself and they are moving too fast and the heat is WAY too low. And I get it, they are worried about burning the whole thing through.

So I try to show them how I would do the same joint. I click the machine up one, usually two steps and have them watch. I go half as fast as they went with more heat.

I usually say they should take some scrap and take it to the limit. Crank the power up and take your time on the bead, expect a burn out. No problems. Keep going, get the feel for the welder, take it to just this side of blowing it all out, thats good and hot and a solid weld. Then I crank it up one more click and show them that you can weld even hotter, just gotta pay a lil more attention and torch control is more critical.

For welding I like HOT, as hot as I can get it in the shortest amount of time. And not for speed, but only cause if I have it cranked up I can gage my speed better. Now every size of parent metal is gonna be diff. And the angle of the joint. But even with 18 ga. sheet metal on car bodies I like heat. The faster I can put the heat down its actually less absorbed heat as if I were to dial it down and dwell longer. Ok, whole nuther story LOL Welding is HOT... JR

10KPete
02-12-2009, 10:05 PM
One of the things I haven't seen anyone mention is arc/puddle manipulation. This is the process of moving the arc, and thus the puddle, in a manner to deposit the weld metal where it is needed to achieve a proper weld.

Such manipulation is required whether one is using stick, MIG or TIG. The manner of manipulation must suit the position of the weld, the desired size of the deposit and the type of parent metal and electrode involved.

Every weld deposit made requires some degree of arc/puddle manipulation.

Arc/puddle manipulation has many different nicknames such as "whipping", "weaving", "circling", etc.

Welding is all about controlling the arc and the puddle to produce the desired result.

The methods and techniques commonly used are easily taught. The rest is simply practice.

I used to tell students (still do) that I can teach them to weld in about an hour. They will then need to practice for about a month to get to certifiable quality levels. This has held true for about 85% of my students. The others just had to find something else to do.

And if you need glasses to read, then you need glasses to weld!!

Pete