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  1. #1
    Randomhead
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    Framebuilding FAQ

    I'm going to put up a framebuilding faq, because we get a lot of the same questions over and over and it's time we had the answers in one place. Here are some of the questions I'm going to include

    Torch to buy?
    Can I use a plumbing torch?
    Can I clear coat a steel frame?

    I'm just putting this up looking for ideas and then I'll make a sticky thread out of it

  2. #2
    Member Smudgemo's Avatar
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    Don't I need a jig? Which jig should I buy?

  3. #3
    Randomhead
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    can I have my aluminum frame fixed?

  4. #4
    Administrator Allen's Avatar
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    Can I change my dropouts?
    Is J.B. Weld suitable for.....
    Can I drill holes in my fork?

  5. #5
    Andrew R Stewart Andrew R Stewart's Avatar
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    Flux- What kind, how much
    Alignment- What kind of surface plates, Bio mechanical VS wheel, BB post
    Miter- Jiggers, hole saws, hand (grinders, files, doweled sandpaper), angle measuring (vernier protractor, drafting), using lug to scribe tube, miter templates
    Brazing rod- silver VS brass/bronze, 50N, cadmium containing
    Stainless steel- brazing rods (Silver 56%, 50N), brazing differences VS 4130, polishing (80-600 grit then buffing)
    Torch tip sizes- .025" to .060" (labeled tip sizes are not actual orifice diameter and not transferable form brand to brand), measure with a drill bit's straight shank
    Tank regulator pressure settings- 4 to 5 PSI each, acetylene max pressure
    Flame style- neutral
    Practice ideas- lug sleeves with .058 wall/.125" larger diameter tubes, building stalagmites, chasing beads around on tube surface, fillet (flowing, internal fillet, outside build up)
    Files- Which kinds/sizes
    Tube blocks- how to make
    tacking/pinning-
    frame design- drawings (full scale/other), design jig (ala Fattic), BikeCad

    Eric- Here are some questions i might consider and the subtopics my answers would include. I don't know much about Cycle Design's flux and fillers so I've made no mention but they should be referenced too. Would this F&Q list be able to be edited or added to over time? Andy.

  6. #6
    Randomhead
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    Andy, I would probably lock it, if anyone posts something faq-worthy I can merge it in or link it

    I would love to see some threads that show basic techniques

  7. #7
    Senior Member ftwelder's Avatar
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    My comment has very little to do with the actual topic and more to do with behavior. It's great to have access to all this great information posted for sure. It is sort of cool however when someone chimes in with examples and info, more personal I guess. I mean I have had posts answered by some big time builders and seen images and received advice I wouldn't have found otherwise. Stickies are great but it's the personal contact that makes forums different. In some (non cycling) forums I have visited, they strongly discourage new posts unless they are totally eclectic and challenging for those with high post counts and well beyond the scope of those new to the info.

    Balance is good.
    1886 Surrey machinists Invincible, 1900 Nashua, 1937 Raleigh Golden Arrow, 1938 Raleigh Silver Record, 1951 Armstrong tourmalet, 1970 Motobecane Grand Record, 1971 Raleigh Professional, 1971 Gitane TDF, 1972 Legnano Gran Primio, 1973, Peugeot PX-10, 1975 Roberts, 1984 Battaglin Giro, 1985 Grandis Speciale, 2012 FTW

    frankthewelder@comcast.net

    le prix s'oublie,la qualité reste ,(michel audiard)

  8. #8
    Randomhead
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    Frank, if I understand you right, you are afraid that someone will ask a question and the answer will be, "read the faq." I don't see anything wrong with someone asking a question that's covered in the FAQ. I might be tempted to delete a post that simply says, "read the faq."

  9. #9
    Senior Member ftwelder's Avatar
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    Quote Originally Posted by unterhausen View Post
    Frank, if I understand you right, you are afraid that someone will ask a question and the answer will be, "read the faq." I don't see anything wrong with someone asking a question that's covered in the FAQ. I might be tempted to delete a post that simply says, "read the faq."
    Nice, I have always liked the supportive nature of this forum.
    1886 Surrey machinists Invincible, 1900 Nashua, 1937 Raleigh Golden Arrow, 1938 Raleigh Silver Record, 1951 Armstrong tourmalet, 1970 Motobecane Grand Record, 1971 Raleigh Professional, 1971 Gitane TDF, 1972 Legnano Gran Primio, 1973, Peugeot PX-10, 1975 Roberts, 1984 Battaglin Giro, 1985 Grandis Speciale, 2012 FTW

    frankthewelder@comcast.net

    le prix s'oublie,la qualité reste ,(michel audiard)

  10. #10
    Senior Member Cassave's Avatar
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    How many frames do I need to sell to get e-rich?

  11. #11
    Senior Member squirtdad's Avatar
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    how do you hold the brazeons in place, like shifter bosses when you are brazing. I just realize I have no clue.... I can see how tubes/lug are held together (jig, pin, friction, etc) but don't have a clue for bosses..... I doubt soft iron wire would work

    probably something ridiculously simple
    '82 Nishiski commuter/utility
    '83 Torpado Super Strada ... cafe commuter
    '89 Miyata 1400
    Soma rush Fixie
    '78 Univega gran turismo (son's Fixie/SS)
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    looking for: De Rosa 58cm ELOS frame and fork internal cable routing

  12. #12
    Randomhead
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    I have a couple of tools for that. There are also commercial products.
    here is my tweeked out version:
    http://flic.kr/p/7v8X4f

  13. #13
    Andrew R Stewart Andrew R Stewart's Avatar
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    017_14A.jpg020_17A.jpg026_23A.jpg

    As the thread turns...

    here's a few home made braze on fixtures. Andy.

  14. #14
    Senior Member clasher's Avatar
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    I just use vice grips that I use for welding all kind of other crap together but I like the little tools that folks make too.

  15. #15
    Member Smudgemo's Avatar
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    I'd like to see a sticky thread for simple home-built tools proving you don't need to tool-up for this hobby as much as some folks think. I love making a tool for nearly nothing that does the same thing as one sold for $50 or more.

  16. #16
    Elitest Murray Owner Mos6502's Avatar
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    Where do you buy tubing, lugs, etc.

    What is the difference, pros/cons of brass vs. silver, etc.

  17. #17
    Randomhead
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    see the supplier thread.

    Good point about filler material, thanks

    Just my take on filler:
    Silver doesn't get the tubing as hot as LFB or nickel silver, this can be good or bad depending on the steel. That's actually a technical enough subject that I refuse to display my ignorance about it.
    Silver 56% will not build into fillets, thus it is best for sleeved joints, such as lugs
    Silver 45% and Fillet Pro: will build fillets, if it isn't cadmium bearing it will be difficult to flow into lugs. This is what I use on stainless where a fillet is needed. Also stainless dropouts. You can use 56% for dropouts if you close up the stay with a plug and make the clearances small.
    Nickel silver: will wet out on stainless, but generally not as easy to use as LFB, a tiny bit more heat required.
    LFB (low fuming bronze): Good all purpose filler. Needs a little more clearance for sleeved joints than silver 56%
    Brazing vs. TIG (GTAW) TIG generally considered a more expeditious way to build a frame. Has advantages in repairs, regular bike construction is equivalent if properly executed.
    MIG: people do this, a lot of recumbents are built with MIG because they use thicker tubing. Not a good idea for a diamond frame.
    Oxy/Fuel welding: People build bikes this way, particularly BMX. Probably not a good idea for most frames.
    Last edited by unterhausen; 03-28-12 at 09:45 AM.

  18. #18
    tuz
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    There is a good set of articles on the metalurgy of brazing here: http://desperadocycles.com/Lowdown_On_Tubing.html

    Apparently a silvered joint is weakened at the joint and some 10 mm further, while a bronzed joint retains most of its mechanical properties at the joint, but is weakened in a region 10-30 mm passed it; you need more butting.

    Here is some data on TIG vs. fillet: http://www.bobbrowncycles.com/eng.htm

    seems the short HAZ of TIG is still quite strong but perhaps brittle.

    But that's if you're skilled enough to apply the minimum amount of heat possible.

    Gas-welding would combine the high temp of TIG plus the long HAZ of brass. Probably okay if the butts are long.

    Edit: I'll add that welding is technically harder. I tried a bit of gas welding. To get a properly penetrated joint, you have to straddle the point at which you're blowing a hole in the tube... though...
    Last edited by tuz; 03-28-12 at 10:29 AM.
    homebuilt commuter, mixte, road and track (+ Ryffranck road)
    bla bla blog

  19. #19
    Andrew R Stewart Andrew R Stewart's Avatar
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    ""Silver 56% will not build into fillets, thus it is best for sleeved joints, such as lugs""

    To add to this- My understanding is that Silver contracts a bit when cooling. So with a fillet where the outer surface first cools and solidifies the still hot core (of the fillet) will contract as it cools, leaving a void or stress fracture internal to the fillet. Andy.

  20. #20
    Randomhead
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    I'm pretty sure that Waterford has used 56% to braze fastback stays on, and it seems like there were some treks that has 56% brazed brake bridges. Of course, I've seen evidence on these bikes that it wasn't a good idea.

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