I have 2 problems, perhaps someone can help

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1) Whenever I weld a 45 (beveled) and grind the weld flat with the metal face, I wind up with these recesses.  I can grind them further and make them vanish but then if you put gloss paint on the area you can clearly see low and uneven areas. How can I grind the welds flat and even with the metal face without having dips? I've used flap wheels and hard wheels.  The areas in question are usually at the edge of the weld metal. Undercut? What am I doing wrong? Anything better than a flap wheel or hard disc?2)I'm still getting used to my new 220v welder. I set it per the door chart and welded vertical up on this corner. What are all the blobs? Too much wire feed? That wouldn't have happened with my 120v Lincoln but I was quite used to it.

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Reply:The blobs are from too much heat for an uphill weld on thin material. Stuff like that I use the zap-zap method, pull trigger and make a nice puddle and let off before it sags, move up a puddle length and repeat. Or if it's thin stuff learn to properly downhill getting good fusion.  The low spots just need slightly more fill without going overboard and needing a lot of extra grinding. And not all angle iron is perfectly flat across the flange.
Reply:So dial the settings down and weld back over the low spots to fill them in?
Reply:I agree with 12V71. In addition, you need to work on welding in such a way that you don't need to go back and add more weld material. You will need to now, that is true. But by getting your settings a little more fine-tuned, you should have less undercut. Another thing to do is work on the bevel of the weld joint. Too much bevel angle causes you to need too much weld, which allows more heat to build up. Try to have the bevel angle lines straight and uniform at both the top and bottom of the bevel. On thinner angle you should be able to establish the puddle, let it build up to a height a little above the base metal, and then move that puddle uniformly across the weld joint. In the photo of the welded and ground area the distance between the outer edge of the weld on the right and the outer edge of the weld on the left is too large, and too uneven. Aim to have the toes of the weld on both sides be parallel and even. Uniform in all aspects. Don't forget that a large part of learning to weld is developing good hand/eye coordination. Best wishes.
Reply:None of this stuff turns out perfect every time. A sandblast and some surfacing primer hand sanded will cover most of the hi-lo stuff.
Reply:The flat weld, on top of the angle iron, shows me that you're not watching the puddle.  Either undercut, or failure to fill the shoulders, is a sign that you're not seeing where the puddle is flowing.  It takes time to get used to watching the puddle, so don't despair.When doing a flat weld like this.............go along steady, but keep "pushing" the puddle back.  When you push the metal back into the puddle, it allows it to fill any voids on the sides.  It isn't "whipping", so don't get crazy with it...........just gently go back into the puddle to build/fill the edges.  You'll see it happening as you watch.  Then you can concentrate on making the bead flat as possible once you've learned this.You can do it with a gentle weave, but it's a bit harder to do.  You risk making some undercut if you go too far out into the parent metal on the sides.
Reply:I believe another problem is prep shape. The weld is adding more material. It needs a place to go. Bevel the joint to allow a place for filler to go. You need considerable heat to melt away steel to displace solid metal, making its own gap. An open root & bevel of 35 degrees each piece can improve the finished weld. Might even behoove you to clamp or weld to firmly hold in exact position then run a .045" grinder cut off wheel through the joint to give a perfectly even gap between.I also question if both faces were exactly in the same plane before welding. I'll assume this is MIG, try welding downhill on thinner stock. That outside corner vertical is a very tough joint to do cleanly vertical up. It needs more space. There is a bit of surface tension to avoid dripping. Think of a drop of water between two surfaces close together, it won't drizzle down. The same drop on a flat vertical surface will drizzle.I grind with hard disk to bring the weld level with the plane of the weldment. For fine finish I'd use a non woven pad. Norton Blaze i(orange) is best, but Home Depot online has black ones cheaper. Lay your disk very nearly flat for the final finish.An optimist is usually wrong, and when the unexpected happens is unprepared. A pessimist is usually right, when wrong, is delighted, and well prepared.
Reply:Depending on your application, if it is just angle iron at 90* I find it much easier and a cleaner joint to cope it instead on a 45* mitre.Burt _____________________Miller Syncrowave 250Millermatic 211Miller 375 Plasma Cutter Hobart Handler 12010FtDrillBit.com
Reply:I'm with Samm ... watch the toes of your puddle and let them fill in longer.
Reply:Knock the feather edge off and reduce the heat.  The chart is not for that joint.  I too cope angle iron joints.  Especially if i have intermediate supports in a frame, then all parts are cut the same.  Also, natural weld grove is created at the corner.I prefer resin fiber disc for finishing.  Flap wheels change shape with use, which I do not prefer.
Reply:

Originally Posted by wb4rt

Depending on your application, if it is just angle iron at 90* I find it much easier and a cleaner joint to cope it instead on a 45* mitre.