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  1. #1
    Senior Member hockeyteeth's Avatar
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    Brazed My First Joint!

    I brazed my first joint tonight using a MAPP torch and 45% silver. I haven't felt so fulfilled in a while!

    Thank you so much to everyone for your help and guidance. I never would have figured out what I needed without you folks.

    I will try to take a picture tonight so you can see how ugly my fillet is. I suppose I'm supposed to break the joint now to test it's strength and penetration?

  2. #2
    Senior Member hockeyteeth's Avatar
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  3. #3
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    Well, fillet brazing with silver is problematic and definitely not the best way to join your first frame. Brass is stronger, cheaper, and much easier to control and although I've never tried a mapp torch, I've heard it can be used for brass with a bit of help to hold in the heat (fire bricks, etc.)
    That said, it looks like you probably had the joint in a bad position to build the fillet (most of it is on the unmitered tube), had too much heat and overcooked it in spots. Go ahead and break it, I'm betting it snaps at the braze and doesn't tear the tube like it should.
    Oh, and I'm not trying to be an ass here, just offering my opinion- it is your first joint after all and it's not that bad considering. We all have to start somewhere!

  4. #4
    Senior Member hockeyteeth's Avatar
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    Thanks for the criticism. I realize silver is terrible for fillets, but I didn't have any lugs and I was just testing the limits of my MAPP torch. I definitely had the tubes positioned poorly at the bottom of a hacked-up steel paint can for heat insulation. I'm not sure what to do about a jig yet.

  5. #5
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    45% silver is fine for fillets, but it doesn't normally build a big fillet, so you have to get a pretty good one. It doesn't get used much because there are structural pitfalls relative to cooling, cracking etc...and at the end of the day it can end up looking even more naked than TIG, which isn't the current style.

    I don't know anything about the science of the the thing, but what seems to happen with silver fillets is that the colder the flame the hotter you have to heat the metal and the dirtier the result. When you have enough heat, the metal doesn't need to be heated as much in one place to get the process to flow, and when it flows, it pretty much jumps into the joint in a nice even fillet without the need to really build it much.

    I find Mapp a little sketchy on small tubes, let alone frame sized tubes. What people end up doing who pushing a little torch too far is they end up with an individual area of deposit they could heat enough, and then they build another. What results is rather like a series of linked spot welds. The difficulty is that areas outside of a "weld" area tend to accumulate contamination. It is extremely difficult to remove this and keep going and indeed there is probably contamination one can't find in recesses of the joint. People have made long lived bikes this way, but it is a little risky.

    I assume you have the correct flux for silver? The one in evidence isn't the one I use, but that doesn't mean anything.

    Anyway, congratulations on setting out on your quest. It is fun to do, and worth the (craigslist?) investment in a hot enough torch.

  6. #6
    Senior Member hockeyteeth's Avatar
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    Today I tried, with no success, to braze some track fork ends onto an old frame using brass rods (alloy 15) and my MAPP torch. I believe the beefy fork ends absorbed all the heat and would not allow the brass to bond properly. I was left with some ugly booger fillets, which I would not feel safe riding. Maybe I will melt the brass and try again with silver.

    A friend who works for a well-known frame builder told me an additional oxygen tank would get my flame about as hot as I need it. What do you folks think?

    Someone is selling and Oxy/Acetylene setup on craigslist for $150, which is a great deal, but apparently I need to be a certified welder to have the tanks filled. I also don't really have the space in my apartment.

    *Sorry to treat this forum as a blog, but I know a lot of people ask about MAPP, so I thought I would share my experiences for their future reference.

  7. #7
    Senior Member hockeyteeth's Avatar
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    Quote Originally Posted by Peterpan1 View Post
    I assume you have the correct flux for silver? The one in evidence isn't the one I use, but that doesn't mean anything.
    I'm using Harris Stay-Silv white flux.

  8. #8
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    Quote Originally Posted by hockeyteeth View Post
    I believe the beefy fork ends absorbed all the heat and would not allow the brass to bond properly.

    A friend who works for a well-known frame builder told me an additional oxygen tank would get my flame about as hot as I need it. What do you folks think?

    Someone is selling and Oxy/Acetylene setup on craigslist for $150, which is a great deal, but apparently I need to be a certified welder to have the tanks filled. I also don't really have the space in my apartment.


    first of all congratulations. i guess your pride on the newborn excuses misusing the board as a blog.

    however i actually plan on gathering some brazing technics myself too, hence i found your board. this whole field of building your own bike and parts is just too exciting to let others have all the fun ( and even get paid for it )

    i did some research on the equipment i need, several people recommended the following setup as a starter. here in germany theres a pretty old company -rothenberger - actually they are the main cause most water and heat pipes are made of brazed copper in germany nowadays, and you can find their sets in each home improvemnt store for small money.


    my friends recommended their starter sets, they include a small gas bottle and a slightly bigger oxygen bottle - both bottles are single use but theres also an option for a refillable oxygen cylinder (over here we can swap them in each home depot) which is of course better for the environment. however, the point is - they are small in size ( approx a pc case size), and lightweight (round 10 kilo or 20 pds), they shall deliver enough performance for one frame, plus tip temp is up to 3100 celsius - enough for brazing and gas welding.
    you can find their products here, ie the roxxy 400 or 120. :

    http://www.rothenberger.com/uploads/...nd_Welding.pdf (page 20) or the smaller ones here:

    http://www.selectselect.net/acatalog...f_Brazing.html

    since i guess you prefer a us product due to the dollar exchange rate i think this will do as well :

    http://www.toolfetch.com/Category/We...9-OX2550KC.htm

    this is just a first find, but it shows what i mean.

    keep on brazing - nothing as satisfying as DIY ... kint

  9. #9
    Senior Member Coyote2's Avatar
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    Geez, I haven't "brazed a joint" in years. I brazed a ton of 'em in college, when I was younger, though.

    Oh, wait, that's not what you meant, is it?

  10. #10
    Senior Member yellowjeep's Avatar
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    I put some split cable stops on a Bianchi that will be built up in march. That was my first attempt at brazing. I used 56% silver wire and an Oxy/MAPP torch. I practiced on a thick assed piece of square tubing by brazing extra stops. After about 4 or 5 i got pretty good at it. I was able to feed the wire in one side and pull the silver out the other with the torch and then use the torch to clean up the silver. Brazing on the top tube was so much easier due to the thinner walls. I should have snapped a picture but i had to get it to the powder coater before I left town. I agree with you Hockeyteeth its a very satisfying feeling and I really am quite proud of my work.

    As far as lugs go I called up Rivendell and they sell practice lugs for 3 dollars each. You don't get to pick and you will not get a full set. I ordered 7 lugs and got 5 DT/HT and 2 TT/DT. I still need to grab a few feet of 4130 from nova to do a little practicing with before I attempt my first frame build this summer.

    In terms of jigs and fixtures I have been researching some homebrew jigs and have found 2 that appeal to me.

    First

    http://www.frameforum.net/forum2/ind...opic=4028&st=0

    Frameforum appears to still be down but it is basically a big sheet of ply wood and blocks of fence post scrap with angle iron bolted on to hold the tube centered for tacking. The idea with this jig is that you have a frame that fits you well enough that you use it as a template and make a replica. I will probably be using this for my first attemt as it will be pretty cheap to build.

    Second.
    http://www.instructables.com/id/The-...g-I-could-com/

    This is a great design in my eyes, it looks like it will do everything I think it should and can be built for around 350 according to the designer. I plan on building one at some point in the near future.

    It seems like you and I are about in the same frame of mind about building. I do a ton of reading on the subject and may have more links or info if you want to send me a PM.

    Cheers
    Last edited by yellowjeep; 01-27-08 at 03:16 AM.

  11. #11
    Senior Member yellowjeep's Avatar
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    One more thought. I have never heard that you have to be certified to have cylinders refilled though I supposed that laws or regulation could differ from state to state. Regardless, at home in KS we have Tractor Supply stores that have a Thoroughbred tank exchange program. It works the same way that propane exchanges do. You have to either (A) buy a new tank from them. or (B) have a tank in good shape that you can exchange for $19+ plus whatever the refill costs. If you have the smallest bottles you don't have to pay the exchange fee ($19).

    I'm not sure what kind of stores like Tractor Supply you have in Gainesville but it might be worth looking in to.

    EDIT: http://www.gaspony.com/welding.htm

    Thats a link to all info about the exchange program. I am on a roll tonight because I can't sleep. There is also a location finder!
    Last edited by yellowjeep; 01-27-08 at 02:49 AM.

  12. #12
    Senior Member yellowjeep's Avatar
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    Quote Originally Posted by hockeyteeth View Post
    A friend who works for a well-known frame builder told me an additional oxygen tank would get my flame about as hot as I need it. What do you folks think?
    Rereading this thread, I'd like to say that I am jealous of your friend and that you have that resource.
    I used a Oxy/MAPP setup and it definitely worked well. I went though 2 O2 bottles (practicing) and I am still not out of MAPP. At 7 buck a bottle thats the only draw back to practicing with Oxy/MAPP.

  13. #13
    weirdo
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    Hey, Yellowjeep- thanks for the tip on getting practice lugs. I`ve been practicing with brazeons and thinking about getting ahold of some tubing to try my hand at fillets, but what I really want to build is a lugged bike and I didn`t know you could buy junked lugs that way.

    BTW, in NV, you don`t need any kind of certification or license to exchange welding bottles either. It works pretty much like you explained for your state.

  14. #14
    Senior Member hockeyteeth's Avatar
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    Quote Originally Posted by yellowjeep View Post
    As far as lugs go I called up Rivendell and they sell practice lugs for 3 dollars each. You don't get to pick and you will not get a full set. I ordered 7 lugs and got 5 DT/HT and 2 TT/DT. I still need to grab a few feet of 4130 from nova to do a little practicing with before I attempt my first frame build this summer.
    Cool. Thanks for the tip! Richard Sachs sells his practice lugs for $5, so that's a good deal.


    Quote Originally Posted by yellowjeep
    In terms of jigs and fixtures I have been researching some homebrew jigs and have found 2 that appeal to me.

    http://www.instructables.com/id/The-...g-I-could-com/

    This is a great design in my eyes, it looks like it will do everything I think it should and can be built for around 350 according to the designer. I plan on building one at some point in the near future.

    It seems like you and I are about in the same frame of mind about building. I do a ton of reading on the subject and may have more links or info if you want to send me a PM.

    Cheers
    Do you read the framebuilder's list, too? That instructable was linked the other day.

    I don't think I'm going to worry about a jig until I have at least one crappy frame under my belt. There are more useful things I can spend my money on.

  15. #15
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    I would try tinmantech, and get the torch and a regulator for oxygen, and run the other side off propane. It is more expensive than the starter sets, but you are just wasting your money, and it isn't that much more expensive. If you already have an A/O set, I wouldn't change it, but for this stuff I would go with the propane. Acetalyne has a lot of nasty tricks up it's sleeve.

    That IS the flux I use so any problems are probably mostly heat control. The hotter your flame the easier it is to braze since the melting of the rod is a composite of the heat of the joint and the heat of the torch that happens to be in the area also, so even though you aren't melting the rod onto the joint like sealing wax, you sorta are... When the heat is cold you have to pump up the joint higher to get the solder to flow, and that is when the bad stuff happens.

  16. #16
    Senior Member yellowjeep's Avatar
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    Quote Originally Posted by Peterpan1 View Post
    I would try tinmantech, and get the torch and a regulator for oxygen, and run the other side off propane. It is more expensive than the starter sets, but you are just wasting your money, and it isn't that much more expensive. If you already have an A/O set, I wouldn't change it, but for this stuff I would go with the propane. Acetalyne has a lot of nasty tricks up it's sleeve.
    Peterpan, can you expand on the use of propane rather than Acetalyne?


    HT, I am on framebuilder's list on and off, I get overwhelmed with all the emails sometimes. But since frameforums.net is still down (where I got the link) I think i might go sign up again.
    Last edited by yellowjeep; 01-27-08 at 09:05 PM.

  17. #17
    Senior Member hockeyteeth's Avatar
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    Quote Originally Posted by Peterpan1 View Post
    That IS the flux I use so any problems are probably mostly heat control. The hotter your flame the easier it is to braze since the melting of the rod is a composite of the heat of the joint and the heat of the torch that happens to be in the area also, so even though you aren't melting the rod onto the joint like sealing wax, you sorta are... When the heat is cold you have to pump up the joint higher to get the solder to flow, and that is when the bad stuff happens.
    Interesting. How can you tell when you have damaged tubing with heat? Is that well past the point of charring the flux?

  18. #18
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    Basically with silver you don't get the part hot enough to glow, and with brass you do. Neither will destroy the steel, depending on what it is. It is more a case of discolouring the flux and getting impurities in the joint. You can burn the steel by overheating it without the protection of flux or blanketing gas. When you hit the right heat, your flux is good, your rod runs easily and you don't have a lot of junk in the filler, and you didn't get any more heat in there than you know you need to. The joint looks good.

    On propane:

    - Gas is nicer it burns cleaner as far as not getting a lot of whispy crap all over the shop, doesn't blow if you drop something on the hoses, or some idiot cranks the pressure. As far as the gasses are concerned in a home environment, Propane tanks out of doors are everywhere, and oxygen is not flamable, so it might help an insurance case a fraction. It is a little cooler which probably doesn't help much for welding, but should be fine for brazing. Might be less poisonous (?).

    - If you already have some propane like a BBQ, you can just handle that out of the same bottle. Maybe the gas co's bottle is safer (?), anyway if you use a ton as with heaters you probably want the larger bottle. I got rid of my BBQ, and intend to use that bottle, and a regulator I have for a forge, so I am saving a little money. I still need to have Oxygen though, at least for the torch. You could probably do lugs in a propane harth set-up without oxy.

    - The propane is a little cleaner in the joint. I really don't have the comparison of all the gasses to go by, but some folks swear by the propane/Oxy set-up. If accet is working for you, no reason to change, mostly.



    As far as welding is concerned, all the above advantages apply, except the Tinman said "life is too short to weld with OXY propane". That didn't bother me too much because I do have TIG, and I'm not in a rush. I do believe they may have made some progress though. They brought out a whole range of tips for propane, and I inquired as to whether these new tips were hot enough, apparently they are fine for welding. I doubt they work as well as accet from the heat perspective, but apparently they work well enough to catalog them. I haven't tested any yet, so I don't know for sure. I will be buying them though.

    I use 4130 mostly, and simple chromo, and don't know about other steels. I do know some people are doing very different steels with propane.

  19. #19
    ǝıd ǝʌol ʎllɐǝɹ I JeanCoutu's Avatar
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    Wait, noob here... Can a frame really be brazed without lugs? I thought you could only get away with that for things like cable stops or rack/fender eyelets. And if this is allright, why do they use lugs?

  20. #20
    Senior Member yellowjeep's Avatar
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    Quote Originally Posted by JeanCoutu View Post
    Wait, noob here... Can a frame really be brazed without lugs? I thought you could only get away with that for things like cable stops or rack/fender eyelets. And if this is allright, why do they use lugs?

    Lugged and fillet are just different styles of building. Lugs can be an out let for creativity. Search for Columbine or Bohemian. They do some of the prettiest lug carving I have ever seen. Dave Wages also comes to mind. Fillet brazing is just as much of an art. The craftsmenship comes in the clean flowing joints that look as if they are one piece. Search for Don Walker or Tom Ritchey. There work is every bit as amazing as the builders that use lugs, just in a differnt way. I love them both.

  21. #21
    weirdo
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    I`ve read that bicycles were brazed for many years in a hearth or forge of some type before gas torches became technologicaly feasible. It seems to me that lugs would have been almost a necessity in order to hold the whole works together (unless they stuffed a jig into the forge with the frame parts). Now that torches make it simpler to direct heat to a localized area, it becomes a relatively easy matter to clamp all the tubes into a jig and hold them in place for tacking, lugs or no lugs. In fact, some designs are very dificult to do with lugs because lugs limit angles, tube sizes, and shapes somewhat- they aren`t manufactured in infinite variables. But they sure are pretty!

  22. #22
    Senior Member yellowjeep's Avatar
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    Valid point rodar.

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