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  1. #1
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    Silver, Did I use it appropriately?

    I did my entire first frame using only Silver, 56 for lugs, but 45 for the seat stays and brake bridge. Seems most use brass in those two locations, I assume for it's increased strength and better gap coverage.

    Bridge2.jpgBridge.jpg

    I've got about 1000 miles on this frame, no problems, but I'm a stick figure compared to most folks. Now that I'm building a frame for my Dad I'm starting to question my process.

    My main concern is whether or not this is safe. Also, if I did use brass on the Seat stay's, won't the high level of heat remelt the already silvered seat lug joint?
    Last edited by bill meyer; 10-02-14 at 03:41 PM.

  2. #2
    Randomhead
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    I am uncomfortable with silver for brake bridges, although if you use something that will build a decent size fillet it shouldn't be a problem. I think your fillets are a little small on the bridge.

    Your seat stays look fine. I don't see anything wrong with silver there. You probably want to make a groove in the seat lug for the stay to sit in to increase the surface area between the two surfaces.

  3. #3
    Andrew R Stewart Andrew R Stewart's Avatar
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    Many frames have and will be made using silver to attach the SS to the ST or the brake bridge within the SS. Assuming (yes I know what that means...) proper prep and brazing I wouldn't be worried. But I would (and I do) file a small relief into the side of the ST lug so that the SS will nestle in one spot and have more surface area with a proper fit/gap.

    If you're still worried then build a test joint using the same techniques as with the frame and test to failure. Remember that the stresses that this joint sees is mostly shear with a little bending.

    But you're right that brass will have a greater gap filling capacity. It also tolerates less clean prep.

    I do my joint in steps using both brass and silver. I brass the lug on the ST and TT. I brass any stay cap on. Then I silver the stay on the lug. Way back when I had more temp control issues and had a silvered lug bleed out silver when brazing on the stays. So I adopted this method. Andy.

  4. #4
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    Great advice, thank you both. Andy, I like that seat stay method, I may try that next go around.
    Last edited by bill meyer; 10-02-14 at 07:07 PM.

  5. #5
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    Not that there is anything wrong with your stay joint, but if you want a stronger joint, try a wrapover style:

    Here is a modernish looking one:




    Or here is a more classic look:


  6. #6
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    I have built many hundreds of bikes using silver for everything but where the stays meet the drops and never had a single failure. Brazed well it will last a lifetime.

    dave

  7. #7
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    Thanks Dave! Maybe some larger fillets around the brake bridge area for extra confidence.

    As for a wraparound stay, something to strive towards, but just getting my caps on and keeping it all together on this frame was hard enough..

  8. #8
    Old fart JohnDThompson's Avatar
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    Quote Originally Posted by unterhausen View Post
    Your seat stays look fine. I don't see anything wrong with silver there. You probably want to make a groove in the seat lug for the stay to sit in to increase the surface area between the two surfaces.
    A couple swipes with a round file works pretty well for this.

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