MIG question

[pthunberg]

I was out in the shop today MIG welding lots of the same part, boring. I got tired of talking to the metal (see Steve’s post “I got caught today”) and I got to thinking. The only way to get the weld bead to have the stack of coins look is to weave or pause the forward motion of the gun. Seems to me this violates the keep the arc at the leading edge of the puddle rule. Does anyone know if this weakens the weld? When I am concerned with strength I use a steady travel and don’t worry about appearance. I have seen several welds posted on this board on critical parts (axels and dif cases ect) that have a very pronounced “stack of coins” look. When welding a coupon for certification I have always used a steady travel. The weld does not look as nice but it usually passed. Is there a method that will produce both a sound weld and a “stack of coins” with MIG? I am mostly self trained and may have(most likley) missed something along the way.

Paul

[tacmig]

Stake of coins?

Everyone has adopted or rather created their own preference for appearance. The bottom line is integrity over looks. But for the customer it seems that looks grants the integrity. Not so, but you have to go with it. In any event, and again we have all developed our "pretty welds". For me I push, pull and circle and move on. This leaves a pretty weld with integrity! Practice this by simply going back (a bit faster than your weld) make a tiny circle (your coin) and moving on to where you left off in your weld. It's 1-2-3. Push, Pull, Circle. My guys tell me it's like watching a baker with a frosting bag. But whatever works. I posted this pic on an earlier post but should work here to.

TacMig

[shorerider16]

Same scenario

I have almost the same dilema. I prefer a steady travel speed with a weave, which when done properly leaves a very nice smooth weld, which I like. However it seems that everyone I work with likes to whip their welds, and don't appreciate anything but their own way. I have often thought that leaving the puddle to let it cool and then coming back to it would reduce strength but I have know testing or data to back me up. The most recent development on the situation comes from my welding instructor telling me that when we are welding with 6010's that we must make our whips as small as possible and not whip ahead of the puddle. Who knows?

If anybody hear has access to proper testing equipment mabye they could test the two different methods and post the results? I know I would certainly appreciate having a definative answer to this age old question.

[aametalmaster]

I do the little circles or whips also depending on what i am welding and the position. I think guys want the stack of dimes look to duplicate a tig weld but that dosen't impress me much as holding together...Bob

[safetydave]

mig question

Hey pthunberg, I belive what you are wanting is what I understand is the "FILLET WELD" method it is were you would do a clockways or counter clockways type weld, this is a slower movement of the weld bead and also it does put more weld on your work project (1) if your flat part is thicher then the vertical part you would do a clockways methed to put more filler on the thicker part and agian if the vertical part is thicker then you would do a counterclockways rotation to put more filler on the thicker vertical metal.

I worked for a company that did all their welding test and welds on all the production work according to a.s.m.e code for pressureized tanks, thats how i started doiong this metod and pretty much still use to this day more then any other weld bead and it does if done correctly looks like a tig weld.

I hope this helps you in your search for the ultimate weld.

[wireburner]

I do the little circles or whips also depending on what i am welding and the position. I think guys want the stack of dimes look to duplicate a tig weld but that dosen't impress me much as holding together...Bob

thats what I also do. I think guys want the stack of dimes look to duplicate a tig weld but that dosen't impress me much as holding together.... exactly

[pthunberg]

Thanks for the info. I have been experimenting with the various gun movements described above. I find the back and circle works well for me. I used to TIG these parts but am trying to speed up production a bit. After cutting through the weld joint I found that the penetration is almost the same as a steady travel. Certainly good enough for this application, although not as good as when I TIG them. Once again thanks for the help, you guys are great.

Paul

[tacmig]

Perfect.

Not a thing wrong with that! Looks as if you tig'd it. Good job!!

TacMig

[diamondback]

stackin' dimes

While there is a time and a place for everything this question covers alot of ground. For stick welding stacking dimes is used to help pre-heat the metal out in front of the puddle due to the lower energy input (11-14 volts and 125 amps for 1/8" 7018). Jump to TIG and there you are dealing with a hot arc but cold wire for filler which takes alot of energy especially aluminum. Here again we are working with settings similar to the ones used for stick. Jump to MIG now. 18 to 30 volts and 150 to 300 amps. Do you see where this is going? The energy input allows for higher deposition rates, faster travel speeds and lower overall energy when done correctly. This makes whipping the puddle inappropriate. Most of the time. There are times when some oscillation is preferred. When the machine or settings just aren't big enough to tie the toes in then some whipping or weaving is needed for the same reason as the stick from before. Also smaller beads and more of them are actually stronger in most cases than one big fat one. The reason is the bottom pass gets somewhat of a heat treatment for grain refinement from the next pass and so on. This is a short answer, there are alot of things to consider when thinking about technique. It is worth the time to check it out.

[pthunberg]

Diamondback. I think I see what you are saying. I find that I use a higher heat setting while traveling steady and can back off a bit if I weave. I have always used a slight weave on fillets while MIGing. In this case appearance is very important, people like the stack of coins look. Personally I am not impressed with how a weld looks….on the outside. I always think lets bend that sucker and see what happens. I see a lot of welds tested for certs in my job. The really pretty ones are not always the winners. These parts are not structural in any way and will never be tested to failure in this application. I would probably TIG them if they were. The sq material in the picture is ½”X1/2”X.065 tube. Pretty small for MIG at least by my skill level..

Paul.

[Jolly Roger]

I never heard of the stack of dimes thing until I came to this board and I've been at this a long time now. I weld 1/2 X 1/2 x .065 and and lighter (don't feel like looking it up in the book right now but think it is .034) with the Mig all the time at around 100 amps. I move along fast and with a slight side to side motion in a downhill fillet leaving a very smooth weld. In a horizontal fillet I push it with very little if any motion. The motion I use varies with the weld position and the material being welded. For uphill I use the same angle and technique that I use running 7018 uphill (the same technique I use for running 6010 uphill as well but with slightly abbreviated motion). I sometimes use the circular motion and a modified Z as well. It all depends on what I am doing. Yes I like a smooth pretty bead, but there are 3 concerns when making a weld in this order: 1 - the proper procedure, 2 - executed properly, 3 - what it looks like. I have seen really pretty welds made with a Mig literally fall apart while sitting in place, and ugly ones you couldn't break.

[FM117]

Some of the "look" is to meet customer expectations and in non critical
apps, I guess is ok.
Example...I have a customer with some equipment trailers, always tearing
up something or wanting racks or brackets etc. About 6 weeks ago
i added some stuff to one of their trailers all 1/4 and 3/8ths thick
mostly flat work. Sprayed it all in with the mig, was all clean new
material, came out textbook perfect. Ran all the beads "smooth"
really looked like a machine applied them, guess what, the driver
who picked it up complained that it didn't look like those beads
he sees on tv.Told him we weren't on TV, basically blew him off.
He goes back and complains to the owner of the equipment that
these welds are no good. Next day owner brings trailer over and
wants me to redo em so they have those "ripples" in em. Ok, they
have been good customers so I run a cap bead over the top to give
the "look" he wants. Sometimes if that's what people want to see
it's easier to just do it. Now all their stuff gets "The Look"!
The guy is just happier than the proverbial pig in %&*#
Dave P.

[pthunberg]

FM117. Exactly my problem with this job. The people buying the product expect ripples. I used to TIG them and that process tends to produce ripples. What a pain! I think the way I am doing the welds will pass the TV test. Still I prefer smoother hot MIG welds I know will pass any test. Sometime I wonder if the chopper and hot rod shows are good for the industry. Actually I know they are, look at all the new welding machines we have to choose from. Some of that must be driven by increased competition and visibility those shows give. After all who wouldn’t want a trailer with a welder on it for their Harley.

Paul

[safetydave]

mig question-stack/no stack

I think by your welds that we see your doing just fine on your weld method and that's what matter's,is what works best for you. NICE JOB ON THE WELDS AGIAN.

[weldpro]

yes people tend to think if you spread the weld all over you got weld. Most generally the more weaving you do the better the chances are you are going to miss an edge that needs to be fused.When welding thick metals over 1 inch, the knife edges to the backing strip must be fused a weaving technique here very seldom gets that job done. We teach people to stringer, multipass welds, some has many as 30 passes.You need to watch your interpass temps, to keep your HAZ within specs.
When welding lighter metals 1/8" and less if you get off the weld joint you miss making 100% penetration.Stringers will get the job done here too. The other thing about using stringers if you mess one up you don't have so much grinding time to correct the smaller mistake of a stringer, compared to the larger puddle of a weave.