Repairing inclusions, lead loading?

  1. OllyO Member

    I have a large casting that has a terible inclusion of slag in it. There was a lug that should be above this area but this failed and ripped a lot of material out with it. The casting is hollow and holds water at around 1.5-2 bar.
    I have had a new lug laser cut from 20mm and this will be bolted in place using the decent material either side of the slag.
    I need to plug the inclusion though to make a fairly flat surface and also to hopefully seal it.
    Cleaning/ grinding it will be nearly impossible I should think.
    I don't want to put any serious heat into ynd casting for fear of it cracking.
    Could I cast lead into this area to seal it off or is that a mental idea?
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  2. oilcooled :)

    oilcooled :) Pipe Welder, Mechanical engineer

    Would a mig braze repair work
  3. OllyO Member

    Never tried it but I think that even with blasting trying to get all the clinker out of the nooks and crannies might be difficult. My thought with lead was that if the casting is hot as well it might just get in there enough to plug it so I can make the mechanical repair without too much worry about its water tightness
  4. awemawson Forum Supporter

    Clean the hole by grit blasting - should come up a treat. If it runs at all hot don't lead load it, lead weakens considerably at relatively low temperatures - consider one of the Devcon filled putties I've found them excellent in the past.

    slim_boy_fat and eLuSiVeMiTe like this.
  5. penfold

    penfold Ambassador plenipotentiary

    Argyll and Bute, God's own country.
    Preheating and NiFe rods should attach the lug and seal up the leak ok; I'd grind the hole back further and fit a patch, possibly with the lug already welded on.
  6. Bill Edwards Member

    Scarborough, North Yorkshire
    To grind it out a carbide burr on a die grinder is your friend.

    Stick welding it cold works well on cast iron but I think you might struggle to get it to good enough metal, it might be a slow process.
    pdg likes this.
  7. AndersK Member

    Couldn't find exactly what I have used before but look at Loctite metal repair putty.

    Used that to fix damaged hydraulic castings to hold pressure with success.
  8. brightspark

    brightspark Member

    devcon or belzona plastic metal
    ronan likes this.
  9. Tigman

    Tigman Forum Supporter

    Watford UK
    Ive smashed a lot of old boilers up in the past , to get them out of boiler houses , when breaking the castings you find a lot of clinker and strange looking lumps inside the boiler sections ! I would try a braze on that hole and maybe braze the tie bar lug on aswell , warm it up gently, braze it up and let it cool slowly !
    WorkshopChris and Parm like this.
  10. ronan

    ronan Member

    I'd use the epoxy resin/chemical metal on that, it was probably cast like that and filled at the factory. Every machine tool i have ever seen has had a chalk like filler sloshed all over the castings, its done very well usually.
    brightspark likes this.
  11. OllyO Member

    Cheers all. I would have favoured brazing these lugs on but I'm not confident enough with big castings like this and if I messed it up that'd be the end of it. These castings would be irreplaceable.

    Long story short I went for a mechanical repair. I'm not sure what people's opinion of my chosen method would be but I'd be interested to hear.

    I filed both the lug and casting until I had a perfect seat then drilled and tapped casting for m8. The lug was also drilled so the cap head screw would be hidden when tie bolts installed.

    I set these on a bed of Belzona 1111 then smoothed it off so once painted it'll look (hopefully) like it's cast- ish

    The lugs don't take much torque and the repair certainly seems solid
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    Last edited by a moderator: Jan 17, 2018
    MattF likes this.
  12. awemawson Forum Supporter

    Good choice I reckon :)

  13. brightspark

    brightspark Member

    excellent stuff and choice :)