How do you repair/improve an imperfect weld?

It depends. I'm assuming you're stick welding using 7018 rod, since that's the one that's so finicky about slag inclusions. If the weld is critical for either cosmetic or structural reasons, the best solution is to grind or scarf away the bead for a short distance including the inclusion, and then reweld that piece. If the weld isn't critical for structure but it is for cosmetic, you can fill with putty before painting.

If you're using e.g. 6011, just wirebrush the weld clean and weld over it.

If you're not stick welding then ???

GWE

This post may not directly answer the OP's question, I hope that other experts here would make some great suggestions. What I want to say is that I like TIG for being able to remelt my welds to make them look nice.

i

You grind or gouge the flaw out and weld again. If you are working as a welder and just run a bead on top expect your walking papers soon. Randy

What would you do to clean and fill the void?

Looking pretty doesn't make a good weld. You can go over and over and over and all you do is make it look better and make it metallurgically worse. Visible inspection of a weld is only part of it. Someone who knows absolutely nothing about welding can pick out a nice looking weld from its opposite.

I was once on a job for Bannister Pipelines. I asked the welding inspector what he looked for in a weld. He said that people who know nothing about welds could pick out 90% of the bad welds just by looking at them, and that it takes testing to find the other 10%.

In the oilfield, only one attempt at a repair was allowed in a pipeline weld. If the second x-ray wasn't good, or anything was suspect, it was a cutout. And that included if the total length of a repair grindout exceeded a certain length.

Mostly, you had one chance to do it right.

Do it once, do it right. After that, you're just making it worse.

Steve

Hmm, I may be confessing to a major no-no ... remember that I'm welding as a hobby weldor only. Sometimes when I have a weld that has more than enough strength, but has a bit of cosmetic deficiency, I do a little pass with

6011. Even though I may not be able to get every bit of slag chipped out before this pass, the 6011 can dig down through it ... or so I have supposed.

Okay, I'm ready for the rebukes to begin!

Andy