Re-welding bad welds

You haven't described what these parts are for. If they are critical structural pieces, you HAVE to grind out and reweld with the original process, but if these are non-critical then you have more options. TIG welding will give more control. If you run into porosity, grind it ou as best you ca. You can use stainless steel or a high nickle alloy filler to kill porosity.

309L would be a good choice.

I haven't, because if I went into it any further I'd launch on a rambling tirade of epic proportions that'd go so far off topic that it wouldn't be anywhere close to reasonable. But, despite that you answered my question to a tee just the same (as you are the undisputed master at that) and it suffices to say that I have a lot more grinding ahead of me than I originally planned....

Thanks for the info! It was exactly what I needed to know. Basically, it's going to have to be MIG all the way and LOTS of advance grinding.

If the weld strength or appearance are critical, then gouging/grinding would be preferable. On the other hand, it's just mild steel of some thickness. Would there be a problem re-welding first with 6010 stick electrode, then grinding back to a correct profile? Or are the bad welds too thick already?

My facilities pretty much limit me to grinding, unfortunately. Which isn't so bad, really, since I do have a good grinder available and I find it a good way to release my aggrivation over the circumstances.

Well, in this case, they shouldn't have needed to ask any questions. They were supposed to know what they were doing, and had provided evidence to that effect, and I foolishly accepted it as sufficient. What I failed to realize was that said individual might hand the welding duties over to someone else, and that the aforementioned evidence of welding ability would no longer apply. The bottom line is it's my fault for believing what I was told and shown, and I bear the responsibility for fixing the situation, even if I was mislead. The price I get to pay is many hours of grinding and re-welding, and hopefully nothing more than that. If I could have sat and watched over the entire process I would have been able to stop it and taken the project elsewhere, but I couldn't, and so I didn't, and there you have it. The moral of this story is, don't believe everything you see and are told, especially when the outcome is important to the success of your project. Also, as they say, if you want something done right you should do it yourself; if you can't do it yourself, find someone you fully trust to do a better job than you could do, not just someone who looks to have the appropriate credentials. If no such person exists, improve your skills until sufficient and then make the time required to do the job right. Otherwise you'll just end up doing the job twice, and the second time around you'll be a heck of a lot more pissed off.

If you have to remove a lot of material, check these out:

They have a pretty coarse grain & last forever. I get them from my welding supplier for about $3.50 each (for 4 1/2"). The Sait rep was in the store giving freebies away. Good stuff.

Hope this helps

Stick's not really an option in my situation, especially since I have no experience in stick welding. But also, the offending welds are much too thick to handle that way. Some of these welds aren't truly critical in the engineering sense, but they're all critical in that I don't want a shoddy looking finished product. Strength is paramount in some cases, though, and those I'll have to grind back as much as is humanly possible. I am beginning to wonder if maybe gouging would be possible, though. I do have plasma cutter access, and the cutter in question would surely be up to the task, it's just that I'm no surgeon with a plasma cutter and I'm worried about making the situation worse. In the end, I'll probably just grind the whole thing. I can get good results with a grinder, and I can leave a nice vee to lay weld material into as well.

I'm tempted to post a picture or two for people to look at, but honestly every time I look at the ones I have to fix it just makes me cringe. It's to the point where if I had the means to travel back in time and stop myself before I agreed to let the guy do it, I surely would.

If you have a plasma unit large enough you should look into getting the gouging tips. I have only used a plasma to gouge once and was impressed. With little practice I found that I could peel away the surface much like I do with the carbon when arc-air gouging. At the least shop for the tips and have them handy next time .... or did you say this will never happen again? :'))))

Randy

Well, sometimes it is cheaper (with time considered as not free) to toss it in the scrap bin and start fresh. Might be easier, too.