6069 aluminum and welding

Discussion in 'Cycling Equipment' started by the blur, Apr 15, 2004.

  1. the blur

    the blur Guest

    does uncontrolled heating/melting of this aluminum weaken its
    "structure"? does aluminum have a structure? can welding weaken a tube
    if it's deformed a bit? why do i ask? i have a new mountian bike frame
    and there's a bulge near one of the welds. the tube is not thin there,
    as there is no defect on the inside of the tube. just a 1 cm by 3-4 mm
    slight bulge on the outside of the tube. the manufacturer will exchange
    it but i don't want to bother if it's just cosmetic. any opinions? i
    have pictures if necesary. thanks



    --
     
    Tags:


  2. vintage

    vintage Guest

    Absolutely. Pic's will help but I think you must accept the
    replacement offer!! It gets serious especially on certain areas of the
    frame where the stresses are at the max such as the joint between
    downtube and headtube where many manufacturers add gussets at the
    bottom. In addition, the joints on the tubes frames go through not
    only tensile or compressive stresses, but also TORSIONS! The bulge
    reduces the tube strength to withstand torsions. Remember how fatique
    aluminum mat'ls are.

    the blur <[email protected]> wrote in message news:<[email protected]>...
    > does uncontrolled heating/melting of this aluminum weaken its
    > "structure"? does aluminum have a structure? can welding weaken a tube
    > if it's deformed a bit? why do i ask? i have a new mountian bike frame
    > and there's a bulge near one of the welds. the tube is not thin there,
    > as there is no defect on the inside of the tube. just a 1 cm by 3-4 mm
    > slight bulge on the outside of the tube. the manufacturer will exchange
    > it but i don't want to bother if it's just cosmetic. any opinions? i
    > have pictures if necesary. thanks
    >
    >
    >
    > --
     
  3. the blur

    the blur Guest

    it's not really close to the actual weld-it's on the side of the top
    tube about an inch from the head tube. it's below a gussett weld on top
    of the top tube. i think its minor-probably cosmetic only. you can feel
    it and see it if the lighting is right. there's no defect on the inside
    of the tube(-i can feel through the head tube)



    --
     
  4. jim beam

    jim beam Guest

    the blur wrote:
    > does uncontrolled heating/melting of this aluminum weaken its
    > "structure"?


    yes

    > does aluminum have a structure?


    yes

    > can welding weaken a tube
    > if it's deformed a bit?


    yes

    > why do i ask? i have a new mountian bike frame
    > and there's a bulge near one of the welds. the tube is not thin there,
    > as there is no defect on the inside of the tube. just a 1 cm by 3-4 mm
    > slight bulge on the outside of the tube. the manufacturer will exchange
    > it but i don't want to bother if it's just cosmetic. any opinions? i
    > have pictures if necesary. thanks


    its not cosmetic, it's structural. take advantage of the manufacturers
    generous offer & have it replaced. to perform a safe repair requires
    substantial work, time & expensive equipment making it most unlikely to
    be an economic exercise.
     
  5. In article <[email protected]>, jim beam <[email protected]> wrote:
    >the blur wrote:
    >> does uncontrolled heating/melting of this aluminum weaken its
    >> "structure"?

    >
    >yes
    >
    >> does aluminum have a structure?

    >
    >yes
    >
    >> can welding weaken a tube
    >> if it's deformed a bit?

    >
    >yes
    >
    >> why do i ask? i have a new mountian bike frame
    >> and there's a bulge near one of the welds. the tube is not thin there,
    >> as there is no defect on the inside of the tube. just a 1 cm by 3-4 mm
    >> slight bulge on the outside of the tube. the manufacturer will exchange
    >> it but i don't want to bother if it's just cosmetic. any opinions? i
    >> have pictures if necesary. thanks

    >
    >its not cosmetic, it's structural. take advantage of the manufacturers
    >generous offer & have it replaced. to perform a safe repair requires
    >substantial work, time & expensive equipment making it most unlikely to
    >be an economic exercise.


    Just wanted to add my comments.
    2 years ago I discovered a crach in my Cannondale bike in the right
    chain-stay. The crach was about 3/4 around the tube about 4-5 cm from the
    dropout, and was caused by an accident 5 years before that.

    I got the frame welded by a friend, who works with metals at the university in
    town. I know that the fram will never be as strong as before, but it is a lot
    stronger compared it's state when I discovered the crack. After all, I have
    been riding the frame with that crack... and not noticed it.

    I now use the bike as a spare one when training in bad weather. The new bike
    is only used during competition and training in good weather.

    --
    Jørn Dahl-Stamnes
    http://spiderman.novit.no/dahls/
     
Loading...
Loading...