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  1. #1
    Senior Member AndyGrow's Avatar
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    Brazing w/MAPP...need some suggestions.

    A few months ago I bought some scrap tube and lugs from Andy @ Strawberry Cyclesport (Terra Nova Bikes). I'm finally getting some time off from work, and want to start practicing brazing.

    My problem is - I am limited to ONLY using MAPP torches. I live in government (Coast Guard) housing, and any sort of welding equipment is prohibited...except for handheld torches (propane, MAPP, etc).

    So, working with that limitation...what are my best choices for rods and flux that will be most compatible with MAPP heat?

    Thanks. And please - PLEASE - don't tell me I HAVE to get a big Oxy/Acetelyne setup. I can't!!
    Andy

    1966 Schwinn Paramount P-13
    1999 Bringheli Custom Road Bike
    2010 Specialized Tricross Sport

  2. #2
    Senior Member Nessism's Avatar
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    Building with lugs is the easiest way to get started in framebuilding. If you use investment cast lugs with the proper clearance for silver (approx. .004"), 56% silver will work great. Use the appropriate white flux and have at it.

    Good luck.

    Ed
    Becareful buying/selling bike parts on-line. I learned the hard way. :(

    Good/Bad Trader Listing

  3. #3
    <>< SoonerBent's Avatar
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    I've never brazed frame tubes into lugs. I have however brazed and welded a lot. I really don't think you can generate enough heat with MAPP gas to get brazing rod to flow properly. The tubing probably conducts the heat down the tube too fast. If it can be done it would be with silver rod. Most silver rod melts at 1100 to 1200 F. Brass / bronze melt at 1200 to 2000 F. MAPP gas says that the flame temp is 2927 which sounds hot enough. But you have to get all the tubing metal at the joint well above the melting piont for the brazing material to flow into every little void. Which flux to use is determined by base material, rod material and temperature during brazing.

    SS

  4. #4
    Matthew Grimm / Flunky Kogswell's Avatar
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    Quote Originally Posted by AndyGrow
    A few months ago I bought some scrap tube and lugs from Andy @ Strawberry Cyclesport (Terra Nova Bikes). I'm finally getting some time off from work, and want to start practicing brazing.

    My problem is - I am limited to ONLY using MAPP torches. I live in government (Coast Guard) housing, and any sort of welding equipment is prohibited...except for handheld torches (propane, MAPP, etc).

    So, working with that limitation...what are my best choices for rods and flux that will be most compatible with MAPP heat?

    Thanks. And please - PLEASE - don't tell me I HAVE to get a big Oxy/Acetelyne setup. I can't!!

    MAPP brazer velonomad has a good list of rods/flux on this thread - look at posting #4

    Velonomad - KOF

  5. #5
    lost in the ozone
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    Scroll down to the "re-cycle" thread. Velo shows how to fillet braze with mapp. I use to belong to the same MTB club as Velo . He has built some nice bikes with mapp gas.

  6. #6
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    Go to a plumbing or welding supply and get yourself an MC acetylene tank and regulator set with a turbo tip. Its fairly small not much larger than the mapp gas and the turbo tips come in various sizes.

  7. #7
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    Hello from Marquette, Michigan! (A fellow Yooper on the shore of The Big Lake)

    Just the other day I was looking around the web for interesting framebuilders and came across Circle A Cycles at http://www.circleacycles.com/. They're an interesting company in R.I. that builds frames and on their website they mention using MAPP gas. Good luck with the framebuilding. let us know how it goes.

  8. #8
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    I.ve been using MAPP to fillet braze a couple of dozen cromo recumbent frames for almost 9 years. A properly done joint seems to be no problem. I even weld with MAPP.

    Tom P

  9. #9
    Yet another vegan biker
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    If you ever find you need a little more heat than your torch provides you can use a heat reflector to capture a few more degrees. I use copper flashing.

  10. #10
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    The biggest problem i see with mapp gas is you hold the whole thing tank and tip. i have lots of experience brazing/ soldering and the ability to have the tip on a hose gives you a lot more room to work with.

  11. #11
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    This thread really got me interested! I've been wanting to try this for a long time, but never thought straight MAPP would do it... So, I figured, what the heck- give it a try - I've only got like 3 frames in the basement that I picked up for nothing because someone rammed a parked car or other tube tweaker. Sure 'nuff-- the stuff got it pleanty hot enough to pry the joints apart on a couple of lugged Reynolds 531 frames. I then managed to add a bunch of small braze-ons (cable guides and such) to a frame I've been meaning to take to a local builder. Saved at least $50, even after investing in a new self-igniting MAPP torch as advised. If mattman is worried about the weight, they (Bernz-o-matic) do sell a version with the nozzle on a hose. I guess he's never sweated water pipes in a basement before (all along the ceiling!)-- working on a bike frame at table top level isn't really that strenuous! ;-) I'm about to order up a few replacement tubes for the frames I've dismantled and see about putting these beauties back together. With luck I'll manage to get them lined up properly and they'll be good to go! You gotta love steel-- try that with carbon or aluminum!

  12. #12
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    Quote Originally Posted by raincrosswrench
    If mattman is worried about the weight, they (Bernz-o-matic) do sell a version with the nozzle on a hose. I guess he's never sweated water pipes in a basement before (all along the ceiling!)-- working on a bike frame at table top level isn't really that strenuous! ;-)
    Nope the problem is i sweat pipes for a living and when you do the amount i do even a mapp torch is bulky and uncomfortable. I use professional quality torches with long hoses and i just can not imagine why anyone making more than one frame would not invest the $100 or so for a decent setup. Its the difference in control between trying to write with a log or a pencil.

  13. #13
    Senior Member atombikes's Avatar
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    I brazed this lowracer recumbent entirely using a Bernzomatic model JTH7 torch and mapp gas.



    This torch has a hose that is several feet long, and DOES put out enough heat to fillet braze. I like the idea about using a shield to keep the heat near the joint. In the past I have used a second propane torch to add additional heat to bottom bracket shells, etc.

  14. #14
    Older I get, Better I was velonomad's Avatar
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    Quote Originally Posted by PaPa
    As a CWI, I experimented with different brazing methods. One of the problems with MAPP, is cost. One student, used 2-1/2, $9.00 bottles to build one frame. Not only that, the larger (non-replaceable) nozzle of these torches is too large to do delicate lug work or braze-ons. The most efficient and cost effective method is propane/oxygen, coupled with a decent torch (Smith AW1A, Victor J series, Harris model 15, etc) w/changable tips.
    Efficiency and cost effectiveness is fine if you plan on building several frames a year. On average most home builders like myself will build 1 frame a year. The rest of the year the Benzo starts the charcoal in the barbeque grill

    2 1/2 bottles of mapp? it wasn't the torch's fault.

    I used less than a full 1lb Mapp bottle to build this frame using a standard Benzomatic tip. Just takes a little practice to learn how to control the heat.




  15. #15
    Senior Member AndyGrow's Avatar
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    Quote Originally Posted by velonomad


    Once again...I let velonomad's pictures do all the talking I need to hear about MAPP!
    Andy

    1966 Schwinn Paramount P-13
    1999 Bringheli Custom Road Bike
    2010 Specialized Tricross Sport

  16. #16
    Older I get, Better I was velonomad's Avatar
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    Quote Originally Posted by atombikes
    I brazed this lowracer recumbent entirely using a Bernzomatic model JTH7 torch and mapp gas.



    This torch has a hose that is several feet long, and DOES put out enough heat to fillet braze. I like the idea about using a shield to keep the heat near the joint. In the past I have used a second propane torch to add additional heat to bottom bracket shells, etc.

    Atombikes can you try posting the pic or link to your lowracer again? It doesn't come up on my computer

  17. #17
    Senior Member atombikes's Avatar
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    velonomad,

    OMG, that bike of yours is beautiful! I have an old Windsor (Mexican built) bike that has polished lugs like that. I plan on doing a restoration on it when I get some free time.

    As for the pic, you're right, I can't get it to work either? Here's the link again (maybe this time it will work?)


  18. #18
    Senior Member atombikes's Avatar
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    Quote Originally Posted by PaPa
    As a CWI, I experimented with different brazing methods. One of the problems with MAPP, is cost. One student, used 2-1/2, $9.00 bottles to build one frame. Not only that, the larger (non-replaceable) nozzle of these torches is too large to do delicate lug work or braze-ons. The most efficient and cost effective method is propane/oxygen, coupled with a decent torch (Smith AW1A, Victor J series, Harris model 15, etc) w/changable tips.
    I don't think you will find too many people that would argue that an oxy-acetylene torch with proper tips and tanks, etc... is a better way to go for people that are doing this type of work in a more or less full time capacity. However, there are many that have never done this type of work before, and want to test the waters. Or perhaps they are only going to produce one frame a year, as velonomad states. Or maybe they work in a shop connected to their house, and they don't want to worry about the instability of acetylene or the cobwebs (soot) that it produces. Or maybe they don't want to sink a minimum $200-$300 for equipment, then pay for tank rental on top of that. Or maybe they would just like the convenience of going to WalMart to pick up a tank of mapp, rather than deal with going to a dealer.

    For those people, there is mapp gas. And I can state that mapp torches are ESPECIALLY good and easy to use for brazeons. I have read that some professional framebuilders use mapp exclusively for all brazeons due to it's convenience.

  19. #19
    Older I get, Better I was velonomad's Avatar
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    Quote Originally Posted by atombikes
    velonomad,

    OMG, that bike of yours is beautiful! I have an old Windsor (Mexican built) bike that has polished lugs like that. I plan on doing a restoration on it when I get some free time.

    As for the pic, you're right, I can't get it to work either? Here's the link again (maybe this time it will work?)

    It works as a link now.....cool bike!

    My bike might be polished and pretty but your bike is much more interesting! You guys who are building recumbents and HPVs blow me away with the creative stuff you come up with!

  20. #20
    Senior Member atombikes's Avatar
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    Thanks for the kind words. I am currently rebuilding that bike, I just finished painting it. I'll post pics when it is completed.

    velonomad, can you give a brief description of how you painted your bike? It looks very good.

  21. #21
    Senior Member atombikes's Avatar
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    I especially am interested in how the lugs were masked for painting, and how the decals (if they are decals) were made.

  22. #22
    Older I get, Better I was velonomad's Avatar
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    detail masking around the lugs was done with 1/4" 3m fineline masking tape .

    The paint is a two step ( base and clear coat) PPG brand, it was pretty easy to apply. I used a small Devilbliss HVLP type gravity feed trim gun ($105) hooked to a 2 gallon pancake compresser. (A friend of mine used a $40 campbell/hausfield gravity feed gun he got from Lowes and it did just as a good of a job as mine) The first round of paint supplies will cost about $100 for the base coat, a quart of reducer, 1 quart or halfgallon of clearcoat and medium activator. It takes me a little more than a 1/2 pint each of Base and clear to paint a diamond frame so the the reducer and clear coat will do about 6-7 bikes. A pint of basecoat costs from $14-$40 depending on the color and additives( pearls, metallics etc). The green I used was a 2005 Jeep Liberty color it cost about $28 for the pint. I used a self etching gray primer from Keystone.

    edited to add: Decals, If you do decals spend the time and money to have them done right or don't them at all
    I never put my name on my bikes in the past, I always felt pretentious about putting my own name on my bikes since I only build for myself. My wife and friends have been on me for years to put my name on my bikes so as a compromise I used the name Conchradha which is a gallic spelling of my last name.
    I had custom die cut lettering cut by a local shop. I sprayed and wet sanded till they looked imbedded in the clear coat, They looked good at first, but now I have lived with it for almost a year I hate them, makes the bike look cheap. I am going to take them off and repaint the frame next winter.
    Last edited by velonomad; 01-25-06 at 09:22 AM.

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