Weld? or Braze?

Discussion in 'Motorized Bicycle Welding, Fabrication and Paintin' started by Greybeard, Sep 18, 2011.

  1. Greybeard

    Greybeard New Member

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    I'm putting a Honda GXH in a '53 Panther. Pretty tight in height but it'll work. The main issue I've had in mockup is the supplied motor mount I got with the EZM kit. It has an issue with the frame on the down tube. To build a mount is very simple. I need to install a 1" by 1.5" piece of rectangular tubing accross the gap, and then use a piece of angle on each side for the motor mount. The angle will be slotted on both sides to give me a fore and aft movement and on top slotted for the port/starboard movement of the motor.

    So to the the question: would you weld or braze the rectangular tubing in place on the bike? My experiece with welding from "the day" is that welding might make the bike tubing more brittle and possibly crack from the vibration of the engine later on.

    Thanks
    Mike
     
  2. GearNut

    GearNut Active Member

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    I would braze it using gussets for additional strength.
     
  3. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    I would agree with GearNut on this as I am limited to brazing in this situation as I don't own a TIG welder. TIG weld or braze are your best options if you can't or don't want to bolt-on.

    dnut
     
  4. Greybeard

    Greybeard New Member

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    I'm limited to having someone else do it for me at this time. I went into a local welding shop, and the man insisted that TIG welding was best, and that brazing was akin to solder, or before they started using TIG systems.
    In the years past, when I had an old buzzbox and a set of tanks, I frequentley used brazing to build split exhaust manifolds for inline 6 bangers. Never had one fail. However, I have had welds fail.
    In the early '60s, my first good paying job was welding high pressure steam pipe, using a torch and a filler rod.
     
  5. GearNut

    GearNut Active Member

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    Tig welding is perhaps the best way if.....if...... the welder really knows what they are doing. Brazing is perfectly acceptable too.
    The problem arises when the base metal becomes brittle directly around the weld bead.
    Tig welding done properly will nearly eliminate this problem.
    Brazing done properly will not get the base metal hot enough to cause this problem.
     
  6. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    If it's aluminium (proper spelling), TIG weld. If not, TIG or braze.

    dnut

    then comes MIG, stick and oxy/ace......
     
    #6 scotto-, Sep 22, 2011
    Last edited: Sep 22, 2011
  7. Maxvision

    Maxvision New Member

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    welding is alot stronger than brazing. But I braze more often than weld. I REALLY like using silver brazing rod with the blue flux coating that you "used" to be able to buy at any hardware store. Dunno why alot of Hdware stores quit selling them. The silver brazing rod is WAY stronger than brass rods. Damn near as strong as a weld.
     
  8. happyvalley

    happyvalley New Member

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    Was it said what the bike is made from?
     
  9. scotto-

    scotto- Custom 4-Stroke Bike Builder

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    Well if it's a Schwinn Panther, we can assume it's a steel frame. TIG or braze or as Maxvision would have it, Silver Solder.......all acceptable and a strong means of permanent attachment.

    dnut
     
  10. Greybeard

    Greybeard New Member

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    I appreciate the responses guys. Haven't pulled the trigger on the crossbrace yet, but the engine is in the frame, sitting on angle irons with bolts between the angles clamping it to the frame..Have been considering spitting a piece of 1" inside diameter tubing, putting it around the frame under the angle, tigging it to the angle and just clamping it so the frame is left unmodefied. The problem is that I'd have no for and aft adjustment with it that way and would have to have it "right"
     
  11. rustycase

    rustycase Gutter Rider

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    Yup
    A quality brazed joint will handle vibration btr than a shabby weld.
    rc
     
  12. Ibedayank

    Ibedayank New Member

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    brazing/silver solder is still used to this day by highend frame builder because it does not get hot enough to weaken the THIN walled cromolly tubes they use
     

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