Critic my weld....

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Just getting settled into welding....by no means a pro; which you will probably be able to see from my beads .....But here is a quick piece I did just to see what you guys think and any advice you can give me.  Welding mostly car stuff....like 4 link brackets for drag car.  Had a question on the undercut that is seen just above the weld...??  Is that normal or an indication I have too much juice?  Unit is a miller vintage....my brand new 210 I just bought quite working and they left me with this unit.Thanks for the advice!
Reply:For MIG in a joint like that if you are getting undercut in the cut piece, you need to angle the gun down more toward the piece which is whole to direct more of the heat there -- the bottom piece in your case.  The whole piece will suck up more heat than the top piece which is being welded at its edge so if you heat them evenly, the cut piece will melt much deeper and quicker.  If you turn the juice down, you may not get adequate penetration in the whole piece.  Does that make any sense?Anyway, try it angling the gun down more toward the whole piece and then cut it apart to see what you have.  If you get good penetration in the bottom piece but are still undercutting the top piece even when the gun is angled down more toward the bottom piece, you might have the voltage up a tad high or the wire speed a tad fast.
Reply:Looks OK, good beefy weld, noticed the undercut as well.
Reply:Thanks guys for the comments......Angling down makes more sense....but being a novice,.....I would have never come to that conclusion.....Another question....I am welding brackets to the frame of my corvette.  The frame is only about 1/8" thick, brackets about 3/16".  On the pieces that I cut out of the frame....I have been playing with welding solely on them....figuring if I can lay a good bead on them without any other pieces present then I should be able to do it with the bracket on there no problem.  In my experiementing on a vertial weld...a downward, slight upward gun angle, and a slight back and forth motion produced welds like above with no burnout....towards the bottom of the weld beams it would slightly get thicker...but not real bad...probably do to heat and the metal running down...However on the same setting, and same gun position/motion; an upward direction blew holes thru the framing like CRAZY!    Why?  Just pushing or keeping more heat in the piece...heat rises right?????  Or would a downward angle on the gun and an upward direction do the same as the ok downward motion.....Next question....how the hell do you keep track of all this!  I made some notes...but how do you know when to use what technique when you don't have a test piece?  Or when there are areas I will not be able to move in a downward direction with my gun angled upward....ThanksThanks
Reply:what gas are you useing ?and for a fillet weld ,you only need a 1/4 fillet on 1/4 stock1/8 for 1/8 and so on putting a 1/4 fillet on 1/8 will not make it stronger.but its a good startChuckASME Pressure Vessel welder
Reply:Torch angle and voltage too high.  Just keep it at 45deg to the root and do a 'zmotion' pausing at the toes of the weld (weak spot for mig).  Otherwise, looks great.  Oh yea, Shouldnt start and stop at the corner.Various GrindersVictor Journeyman torch200cf Acet. 250cf oxygenLincoln 175 plus/alpha2 gunLincoln v205t tigLincoln 350mpEsab 650 plasmaWhen you can get up in the morning, Its a good day.Live each day like its your last.
Reply:Originally Posted by ski_dwn_itThanks guys for the comments......Angling down makes more sense....but being a novice,.....I would have never come to that conclusion.....Another question....I am welding brackets to the frame of my corvette.  The frame is only about 1/8" thick, brackets about 3/16".  On the pieces that I cut out of the frame....I have been playing with welding solely on them....figuring if I can lay a good bead on them without any other pieces present then I should be able to do it with the bracket on there no problem.  In my experiementing on a vertial weld...a downward, slight upward gun angle, and a slight back and forth motion produced welds like above with no burnout....towards the bottom of the weld beams it would slightly get thicker...but not real bad...probably do to heat and the metal running down...However on the same setting, and same gun position/motion; an upward direction blew holes thru the framing like CRAZY!    Why?  Just pushing or keeping more heat in the piece...heat rises right?????  Or would a downward angle on the gun and an upward direction do the same as the ok downward motion.....Next question....how the hell do you keep track of all this!  I made some notes...but how do you know when to use what technique when you don't have a test piece?  Or when there are areas I will not be able to move in a downward direction with my gun angled upward....ThanksThanks
Reply:Turn the heat way down for verticle up.  Some guys can weld down, I was taught to weld up only.  Its stronger when done right.  In a good verticle up weld you can watch the wire go into the plate, then wait for the hole to fill up with weld before moving on.  This will get rid of the undercutting.  Its like painting with Enamel, put on as much as you can just before it runs.  It does take time to learn to weld up, but worth every bit of it.  The hot metal will follow the heat even if it defies gravity.  Turn your heat and wire speed down 50%, learn to weld up and keep turning the heat ( wire and volts) up until it looks nice and smooth.  Keep going hotter until you can't control the puddle and back off to where you can.  Nothing is as important as the pause at the sides.   You will get it in time.Keep your eye on the donut, not the hole.  WATCH the PUDDLEDavidReal world weldin.  When I grow up I want to be a tig weldor.
Reply:Angling down makes more sense....but being a novice,.....I would have never come to that conclusion.....
Reply:Originally Posted by ski_dwn_itNext question....how the hell do you keep track of all this!  I made some notes...but how do you know when to use what technique when you don't have a test piece?  Or when there are areas I will not be able to move in a downward direction with my gun angled upward....
Reply:Thanks for all the great comments....they are all greatly appreciated.  These welds are literally about the 3rd time I have ever welded.  It always facinated me on shows watching them and never was really around anyone that could, and when I was the other around would say.....its nearly impossible to do right.......I like to do the impossible though.  Had one of our maintenance guys come over to the house tonight....he welds quite often and knew I was getting this unit...I am in management and I could tell by the look on his face when I was asking about what unit to get and stuff that he was thinking......just bring me what you want to weld and leave that stuff to the experts.  But tonight that piece was setting there and I was showing him a mill I bought and the cars......and he picked it up and said - who welded this??  When I replied that I did - he said - not too damn shabby.  Felt pretty good.  Anyways....back to the main topic.......many of you mention the weld pool....can you describe in more detail what I should be looking for and doing with it.....LOL.  When I was welding the stuff that I have been doing like the piece above, I found that keeping the wire at the leading edge of the pool seemed to work the best....also recall there being a dark spot that seemed to trail behind it and seemed to float around side to side with my motions.....maybe I am nuts what I think I saw.....but can someone help piece all this together....I will try the vertical with much less voltage and wire feed and see if I can get that worked out.....again though; faced with a piece that you need to weld - how do you know where to start and how to do it....perhaps its just expertience that tells you what you need to do.  I race cars on the side and suppose its like me when I launch the cars - the instant something out of the norm happens I can tell the tire spun a hair or she really is hookin.....where someone not familiar with the situation would probably by crappin their pants!   Here is the one car I drive..and the other...This is the one I am putting a solid rear conversion into and doing the welding for....coming along pretty good and almost ready to do the final welding...Again thanks for all the help!
Reply:....also recall there being a dark spot that seemed to trail behind it and seemed to float around side to side with my motions.....maybe I am nuts what I think I saw.....but can someone help piece all this together....
Reply:Well I'm up late tonight so I will try to answer your questions as best I can.But first, I like your analogy about crapping pants.    Exactly -- you know what to do 'cause you've seen it and done it a zillion times.  Same with the MIG welds you are doing now.  Only way is practice.For the puddle, at first, try to keep it uniformly spread at the junction of your two materials -- a nice straight weld of uniform width.  You can make the puddle wider by slowing travel or narrower by speeding up.  You can also affect it by increasing the stick-out -- moving the gun a little bit farther away will tend to reduce the heat at the weld a bit and pushing it in closer will up the heat.As you get more comfortable making straight, uniform beads, start watching penetration at the weld toes.  Folks here more expert than I have already explained motions you can make with the gun to increase heat and fusion at the toes.  If you watch the puddle, you can actually see it fuse at the edges instead of looking like sort of water beading on a fresh wax job.  Again, a little bit of practice and all the stuff you are watching becomes more and more of second nature.  Like at first make sure you are moving nice and straight.  Next, uniform bead width.  Next, full penetration at the toes, etc.If the puddle is about to blow through, what I notice is it starts to sort of "flutter" for a split second -- I don't know how else to describe it.  Try it and you will see what I mean.  Another indication is that for a given metal thickness and orientation, the puddle can only be a certain diameter before it will usually blow a hole.  When the puddle grows beyond that familiar size, you know it's about to make a hole.  Again, a little practice and you'll just know -- you won't even have to think about it.You usually want the wire to touch the puddle at the leading edge.  If you move the wire more toward the center of the puddle, usually that will just squirt molten metal at the weld and penetration will be poor.  You want to weld by getting the work melted too, of course not just run melted steel wire over it.The black spot is likely slag floating to the weld surface.  If you clean the metal better before welding, it will very likely disappear.  Depending on the weld quality you need, it might not matter.  If you notice slag inclusions at the weld toes, clean, clean and then clean some more before welding.If faced with a weld where you are not sure exactly how to handle it, ask somebody here.  They can likely get you in the ballpark.  A test piece is also best.  Failing that, make your best judgment of how to do it and try.  Watch the puddle.  If things start getting terribly wrong, let go of the trigger, grind out the bad weld, make adjustments and try again.OK, this is getting long winded.  Try again and post more pics.  You are doing great for only doing it a few times.Last edited by phila.renewal; 03-28-2007 at 01:01 AM.