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Repair a bad weld

Posted: Wed Aug 26, 2020 9:55 pm
by Kfactor239
Jody,
Could you do a video on how to grind out a bad weld and run a new weld? When you should and shouldnt, how bad is ok. I primarily do tig and mig mild steel. There are plenty of videos showing how to do thing right but what about when you mess up. I think it's a part of the learning process that is missing. What to do when you screw up.
Thanks,
Kenny

Re: Repair a bad weld

Posted: Wed Aug 26, 2020 10:41 pm
by Oscar
Sorry to burst your bubble but Jody doesn't actively participate in the forums. Hopefully he does read this, but I wouldn't hold my breath. To me its pretty simple. You grind it out and re-do it when it is "not up to par". How you define "up to par" is up to you, but to me I look at the angle of the toe to the base metal, aka how well the weld wetted in, as well as the overall size of the weld bead. Too cold, and it will be too "piled up".

Re: Repair a bad weld

Posted: Wed Aug 26, 2020 11:31 pm
by Poland308
When in doubt grind it out!
How bad is too bad becomes a matter of perspective. I recently was part of a crew of 4 guys, we welded out a 14” 900# flange on sch 160 pipe. Because it was power house code work the standards were a little less stringent than boiler code work. We were allowed to have up to 3 imperfects per inch of weld, but none of them could be over 1/16”. Note that sch 160 pipe at that size is about 1.75” thick. It had a tig root and the rest was 7018 stick.

Re: Repair a bad weld

Posted: Thu Aug 27, 2020 12:53 am
by tweake
Kfactor239 wrote:Jody,
Could you do a video on how to grind out a bad weld and run a new weld? When you should and shouldnt, how bad is ok. I primarily do tig and mig mild steel. There are plenty of videos showing how to do thing right but what about when you mess up. I think it's a part of the learning process that is missing. What to do when you screw up.
Thanks,
Kenny
jody has done video's of repairs and repair mock ups.
its basically the same situation. the techniques are the same regardless of how the mistake was made.
when you should or shouldn't is really subjective. depends a lot on what it is and what its used for. you have to decide what is "fit for purpose".