Results 1 to 5 of 5
  1. #1
    mtbr member
    Reputation: robselina's Avatar
    Join Date
    Oct 2008
    Posts
    129

    New question here. Advice on quick/dirty steel tube repair

    I have a cheap, and I emphasize cheap, single-speed commuter project. It's a late 80s Bianchi Broadway I picked up at the thrift store and resuscitated. I'm going to go back to grad school next semester and need something to put around campus mostly. I don't want to take anything I'd miss when it gets stolen (odds are against me on this )

    Anyway, in the process of cleaning it I found two cracks in the frame. It's a steel frame with lug construction. Worst crack is right after the lug on the top tube. The other one is in the same spot, right after the lug, but on the down tube. You can see the top tube damage in the photo below.

    The bike is up and running and I'd like to correct these as best I can with the means available to me. I am OK with a MIG and have a Millermatic 175 here at the house along with the usual metal working/prep tools that go with it.

    I see a few options:

    1 - Not worry about it. Ride it 'till it breaks or gets stolen.

    2 - Drill a couple of small holes at the end of each crack to stop them from growing. Clean and prep, then run a little bead over the crack with the mig.

    3 - Drill and prep as in #2, but put a little gusset plate over the crack and weld that in place to distribute the load/heat a little better.

    I realize both the welded options will put a some heat into thin steel. If I do the gusset plate, I won't fully weld it to reduce the HAZ....I also would let it air cool of course.

    Reading up on these forums, it seems that brazing is the preferred method of assembly. We do have an oxy-acetylene torch set at work and I'm sure one of the guys will help me braze on a gusset plate if that is a better approach.

    Would brazing on a gusset be a better solution? Any other ideas I haven't thought of that would make more sense?



    Thanks in advance for any feedback!

    Rob

  2. #2
    pvd
    pvd is offline
    mtbr member
    Reputation: pvd's Avatar
    Join Date
    Jan 2006
    Posts
    2,795
    since this is a pure ghetto fix...

    I'd drill the two holes to stop propegation and braze a cussett plate over the area. you should probably use brass since the lug has surely been brass brazed an you will be safe with a common filler. trim the lug back a bit to give the bandaid some extra cover.

    then..

    ride the piss out of it.

  3. #3
    mtbr member
    Reputation: robselina's Avatar
    Join Date
    Oct 2008
    Posts
    129
    Thanks for the feedback.

    Now I've just got to figure out how to make a gusset that will fit well enough for brazing Hopefully I can find some tubing with the right I.D and wall thickness.

  4. #4
    pvd
    pvd is offline
    mtbr member
    Reputation: pvd's Avatar
    Join Date
    Jan 2006
    Posts
    2,795
    just get it close and bend it closer by hand. it's not rocket science. keep it ghetto. i think that you are over thinking this.

  5. #5
    mtbr member
    Reputation: robselina's Avatar
    Join Date
    Oct 2008
    Posts
    129
    Quote Originally Posted by pvd
    i think that you are over thinking this.
    Probably true - I have a tendency to do that.

    Looks like I have some scrap in the garage that will work fine for this.

    Thanks,

    Rob

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •