frame welding

Discussion in 'Cycling Equipment' started by Joe, Apr 12, 2003.

Thread Status:
Not open for further replies.
  1. Joe

    Joe Guest

    I'am having a frame built w/true temper s-3 tubing, the instructions that came w/tubing recommended
    tig welding; my builder is well known and respected, however he filet brazed the frame and I'am
    concerned about the strength. He made a good point that tig welding create's more heat stress than
    brazing. Any frame builders W/opinions welcome. Thanks
     
    Tags:


  2. Ted Bennett

    Ted Bennett Guest

    Joe wrote:

    > I'am having a frame built w/true temper s-3 tubing, the instructions that came w/tubing
    > recommended tig welding; my builder is well known and respected, however he filet brazed the frame
    > and I'am concerned about the strength. He made a good point that tig welding create's more heat
    > stress than brazing. Any frame builders W/opinions welcome. Thanks

    Your builder is right about the heat, but True Temper S-3 is designed to be welded, with thicker,
    shorter butts to prevent unacceptable weakening of the area of the joints.

    Welding is very common these days because it takes less time than brazing, either with lugs or with
    fillets. Because welding can be regarded as uncontrolled casting, either the tubing must be extra
    thick at the joints, or preferably also heat treated afterwards, as pretty much every aluminum frame
    (and lots of steel) is done. Many purists want only brazed, probably because they like the looks of
    nicely done lugwork.

    Bottom line is the skill of fabrication, in any method of joinery. There is no downside to what your
    builder has done, and I'll wager that the frame comes out a little prettier.

    --
    Ted Bennett Portland OR
     
  3. In article <[email protected]>, Joe <[email protected]> wrote:
    >I'am having a frame built w/true temper s-3 tubing, the instructions that came w/tubing
    >recommended tig welding; my builder is well known and respected, however he filet brazed the frame
    >and I'am concerned about the strength. He made a good point that tig welding create's more heat
    >stress than brazing.

    It's a steel tube. It's OK to fillet braze it. A tigged joint would probably be stronger but brazing
    is "strong enough" - they don't have a problem coming apart at the joints unless the welder makes a
    mistake. And TIG welding mistakes can be pretty awful too. If the builder is competent and careful
    then the bike is safe.

    People fillet-braze Reynolds 853 as well.

    --Paul
     
  4. Jim Beam

    Jim Beam Guest

    By "fillet brazed" you mean lugless brazing, right?

    If that's the case, then yes, it's not being joined according to manufacturer spec. Your builder's
    point about TIG creating "more heat stress" is simplistic. Does brazing create less "stress" due to
    temperature? - Yes. That used to be a concern with non-air hardening tubesets as their strength
    degraded at high temperatures. But your S3 tubeset is *air-hardening*. It /needs/ sufficient
    temperature elevation in the weld zone to start the hardening process.

    *Low temperature* lugless brazing looks pretty but almost certainly does not comply with True
    Temper's spec and so your tubes will not reach their full design strength in the high stress zones
    of the joints. I'd check the tube spec, which I believe will give a minimum braze temperature for
    air hardening to occur, and check with your builder to see if his brazing method met those criteria.

    Jim

    Joe wrote:
    > I'am having a frame built w/true temper s-3 tubing, the instructions that came w/tubing
    > recommended tig welding; my builder is well known and respected, however he filet brazed the frame
    > and I'am concerned about the strength. He made a good point that tig welding create's more heat
    > stress than brazing. Any frame builders W/opinions welcome. Thanks
     
  5. Jon Isaacs

    Jon Isaacs Guest

    >I'am having a frame built w/true temper s-3 tubing, the instructions that came w/tubing recommended
    >tig welding; my builder is well known and respected, however he filet brazed the frame and I'am
    >concerned about the strength.

    Curious who the builder is?

    jon isaacs
     
Loading...
Thread Status:
Not open for further replies.
Loading...