Featured The Gearbox is Cracked, please help

Discussion in 'Gun Building, Modifications & Repairs' started by BeansOnToast, Jan 4, 2021.

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  1. aotsukisho

    aotsukisho Well-Known Member

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    Soldering will not work, it is not meant to make a strong bond. Just like JB weld it does not modify the workpiece surfaces as it is just epoxy that contains steel particles. You need to make a weld in order to make a bond comparable in strength to the original material.
     
  2. OutlawAirsoft

    OutlawAirsoft Member

    43
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    Hamilton
    You would have to do a pretty darn neat welding job to work. I imagine things would get caught on the bead.
     
    aotsukisho likes this.

  3. Guges Mk3

    Guges Mk3 Well-Known Member Staff Member Supporting Member Lifetime Supporter

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    This is what I want someone to try...



    Go to 3:00 mark
     
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  4. aotsukisho

    aotsukisho Well-Known Member

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    Yep agreed it will be difficult, probably not worth the effort unless the gearbox is a one-off

    Brazing is more like soldering than welding, there is similarly no modification of the substrate. It is a lot stronger than soldering, but if the gearbox cracked because its original homogeneous alloy strength wasn't strong enough then a braze isn't going to fix it.
     
  5. Guges Mk3

    Guges Mk3 Well-Known Member Staff Member Supporting Member Lifetime Supporter

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    You don't think it will hold together in the crack area?
     
  6. aotsukisho

    aotsukisho Well-Known Member

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    Don't think so, brazing fill has a lower melting point than the material being brazed and as such will not be stronger. The crack will be on the weakest point already, so it needs to improve the strength of the original alloy for it to be a useful fix.
     
  7. Guges Mk3

    Guges Mk3 Well-Known Member Staff Member Supporting Member Lifetime Supporter

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    I'm not thinking it will be stronger, rather, it will put a mechbox into service that is "within" spec.

    As "we" know Americans like overdriving items beyond spec...but then...this is an APS box...and that braze could possibly be stronger...
     
  8. kazuchan

    kazuchan Member

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    these days the gearbox shell more cheaper, I rather buy another cheap new ( or up to CNC one ) than try to fix them.
     
  9. BeansOnToast

    BeansOnToast Member

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    Seattle
    Same, that's definitely the path I will be going
     
  10. Guges Mk3

    Guges Mk3 Well-Known Member Staff Member Supporting Member Lifetime Supporter

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    You want to know how much it costs to diecast a mechbox shell.

    Last price I had from 2014 was 37 cents per set in qty 5000