RockyD , Dan - MIG JOINT ADVICE

[davejurek]

Rocky, Dan,

Thanks for all the advice you gave me on welding fillet welds. I am able to reproduce pretty nice beads. I am still unclear on how to detemine the heat though as I was able to reproduce similar beads on heat settings 2, 3, and 4 on my machine. 4 was definately hot!!! (My machine heat settings ranges 1 - 6).

Other question I wanted to ask, is I'd like to tackle some outside corner joints next. Can you show me some examples of outside corner welds? What kind of procedure do I need to be using? Material I'll be practicing on is the same, 14 gauge.

Thanks.

Dave Jurek

[Guest]

Re: RockyD , Dan - MIG JOINT ADVICE

Originally posted by davejurek
Rocky, Dan,

Thanks for all the advice you gave me on welding fillet welds. I am able to reproduce pretty nice beads. I am still unclear on how to detemine the heat though as I was able to reproduce similar beads on heat settings 2, 3, and 4 on my machine. 4 was definately hot!!! (My machine heat settings ranges 1 - 6).

Other question I wanted to ask, is I'd like to tackle some outside corner joints next. Can you show me some examples of outside corner welds? What kind of procedure do I need to be using? Material I'll be practicing on is the same, 14 gauge.

Thanks.

Dave Jurek

Dave, fit up your joint corner to corner and then fill up the V. I don't really trust a outside corner joint by itself without welding the inside as well, on something structural. In the previous example, I was thinking of 3/16" and above.

On 14 gauge, you can get 100% penetration, so this joint will be strong as the base material. I suggest welding vertical down, and stay ahead of the puddle. No weaving on this one. Ya gotta go fast. It should have a nice rounded appearance to it when done right.

[davejurek]

Rocky,

Any advice about setting up the heat on a mig? How do you know when your too hot or not hot enough? When I was posting all those examples, you guys kept telling me to turn the heat down but I never understood why.

Got any pics?

Dave

[Guest]

Originally posted by davejurek
Rocky,

Any advice about setting up the heat on a mig? How do you know when your too hot or not hot enough? When I was posting all those examples, you guys kept telling me to turn the heat down but I never understood why.

Got any pics?

Dave

The "heat" is controlled by the wire feed setting (WFS) and affected by the voltage...so to turn the heat down, turn the WFS down and the voltage, too. I most always use .035" wire and for that, I start out at 19 - 22 volts and light off the torch and while welding, adjust the wire feed till it looks and sounds like I want.

i did a military cert in 3/8" mild steel plate and they set the voltage at 19 volts and we could only change the WFS. Used 50 - 50, AR - CO2 gas too. So I still like it around 19 volts. I Ran miles of wire at those params. With the one setting, I could weld all position without changing anything....had to...the machine was too far away to keep changing parameters.

[davejurek]

Yes, I understand what the heat is but you guys didn't know what heat I was at. You advised me to turn down the heat based on the pictures I posted. HOW did you know I had too much heat? What are you looking for in a good weld.

The disadvantage here is I don't have the experience to look at a weld and determine the adjustments needed.

Dave

[Roger]

Many welding books post series of pictures of problem weld beads then captions say what caused that bead. Army welding manual is best on line for free but only problem weld bead picture series is figure 10-40. Army welders learn all about good and bad welds while welding so don't have more bad weld pictures. Here's link to that manual.
http://www.adtdl.army.mil/cgi-bin/at.../9-237/toc.htm

Your first weld's that were much too hot had ripples with little deffinition so they looked like spray transfer welds. Welds that are too hot will have flat face or concave face. Good weld beads face have slight arc and nice even ripples in arc (((((( shape. Hot fast bead will have flat face and ripples drawn out into more of V shape.

Increasing volts without increasing feed rate increases arc length. Make some straight beads without weave and tell us how voltage changes affects your beads. If your voltage gets too high without increasing wire speed or stickout you could damge tip.

[Roger]

Your striving for flat bead profile which fits your use still bead face should be a little convex. Concave bead face or undercut is bad. Convex section of bead face is called reinforcment.