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  1. #1
    Join Date
    Jan 2014
    Posts
    2

    Default Welding repair to a crack in an excavator boom.

    I have a mini excavator - Volvo EC25. Years back I had a thumb installed, which included having someone weld a clevis bracket on the boom. The individual did a great job, only welding the vertical edges to the boom. There is now a small crack starting on the corner of the boom just above the bracket, which is about 1 1/2" to 2" in length - half of the crack goes across the back of the boom and the other half along the side. I didn't trust myself to weld this so I got some ballpark figures, which turned out to be more than I want to pay. In reading other forums my intent is to remove the paint, V notch along the crack, drill holes at the start and end of the crack and finally weld. I am intending to use 7018 rods. Any suggestion or advice? Should/can I grind the weld flush when done?

  2. #2
    Join Date
    Jan 2004
    Location
    Ohio
    Posts
    56

    Default Boom repair

    I've welded a few booms in my day, I would grind the paint away. Then v grind the crack.grind all the way down to the bottom . I like to use dye pentatrant to make sure I'm at the end of the crack. Once that's done, you can drill a small hole at both ends. Then use preheat no more then 200 degrees.Use new 7018 that's not been open burn in a good root pass. Depending on the thickness of the boom you might have to multi passes to complete your repair. I don't like to grind the weld flat, that to me takes away from the strength. Only grind if it's in conflict of other parts or areas. Keep the heat no more the 500 degrees. Put back into service. It's good to try to figure out why it cracked. Either misuse or fatigue .sometimes if you have the option I also plate the area for extra strength . Hope this helps. Happy Welding
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  3. #3
    Join Date
    Sep 2005
    Location
    northern NJ
    Posts
    1,853

    Default

    Vee it out & weld it up. I've used 7018 stick, Hobart 21B innershield & ESAB 7100 ultra outershield & never had an issue. Being a mini exc. the boom is most likely fairly thin.

    Don't over think it just make sure you clean everything up between passes.
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