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  1. #1
    mtbr member
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    Begging for tube scraps

    I'm hoping there's someone out there with a box of tube ends they'd be willing to pack and ship to a new hobby builder for handmitering/brazing practice.

    I'm willing to paypal for materials and shipping. Hoping to spend less than I would just buying straight guage .035" tube.

    Shipping would be to the Chicago area (west suburbs actually)

    I have tube blocks for 1 1/8" and 1 1/4", but I'd be very happy to have any size for practicing.

    Please let me know if you're able to help.

    Thanks!

    Mike

  2. #2
    Moderator Moderator
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    I always have lots. Shoot me an email.

    -Walt
    Waltworks Custom Bicycles
    Park City, UT USA
    www.waltworks.com
    waltworks.blogspot.com

  3. #3
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    A good source of tubing for practice is trashed bike frames from dumpsters, etc. Some bike co-ops get a lot of junkers they are willing to sell cheap or give to you. You will have to remove the paint before brazing and it's not chromo most of the time but its an inexpensive alternative to buying tubes. You also have a variety of diameters to practice on such as chain/seat stays, fork blades, etc.

    Brian

  4. #4
    builder of frames
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    Mike, I suggest using only one short tube per practice braze and having the other be longer so you can better position the joint. I assume you will be fillet brazing and part of your success is based on not only how you move the torch but also how you position the joint (in reality how you keep repositioning the joint as you add filler around the miter). My students have a hard enough time keeping track of both hand motions and if the tubing is too close to the wood block of course they are going to scorch it. It is also easier at the start to have a smaller diameter 2nd short tube compared to the larger diameter long tube. While of course it is possible to have them the same diameter, it is smart at the start to have at least 1/4" or more difference. As you gain experience you can get closer to the same diameter. It takes more skill to add brass around the ears of the miter that wrap around a tube. As a matter of fact it isn't a bad idea to braze a small piece of seat stay sticking straight up on the larger tube just to get the feel of melting brass without having to move the joint during the process.

    As you braze around the miter you want to position both tubes so they are equal angle from vertical. Otherwise the brass is going to run more one way than the other rather than into the valley. This means you are constantly moving the long tube. If the long tube is too short it will be hot and that adds a another layer of complexity because you have to use gloves or pliers and that takes time and then the joint is cooling etc.

    It is a mistake in the beginning to try and get by with too many compromises from ideal (wrong size or too short or too heavy tubes or rod or flux or torch and tip). It is a common rookie mistake to get by with whatever. That contributes to difficulty, increases mistakes and makes it easy to get discouraged. Of course you know that I'm going to say it only makes sense to learn from an experienced teacher but that is another subject .

  5. #5
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    Doug,

    I sure appreciate all the information you share here. It means a lot, especially coming from someone who typically charges for sharing their expertise.

    I'm trying to limit my compromises. I've been collecting supplies for a while and have paragon aluminum tube blocks, cycle design LFB and flux, and the soon torch supplies you've recommended so often. I also have a park clamp like I've seen so many builders use. I hope to tack braze each joint using the blocks on a flat 1/2" aluminum plate, then move the assembly to the clamp. Does this sound like a productive way to practice?

    I know using propane will make it a bit harder to fillet braze. I'm willing to fill my dads old acetylene tank if I'm not able to get on.

    I understand that proper hands-on instruction would accelerate the learning curve substantially. I would surely consider it, especially given my proximity to you. Getting a large chunk of time off from my dayjob is challenging and I get a lot satisfaction out of putting time in to hone a skillset.

    Thanks again to all who have been so helpful. I'm now waiting on proper torch equipment and practice tubing. Can't wait to get my hands dirty.

  6. #6
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    Can you get some tubes on sale from bikelug.com? Here's some 34.9mm 1.2/0.9mm tubing for $2! BikeLugs.com
    You don't want my scraps, I'm pretty much a scrooge
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    cheers
    andy walker
    If you can't get an account, or there's a min order, I'll sell you some

  7. #7
    builder of frames
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    What I was trying to explain was that having 2 short pieces of tubing makes it hard to keep adjusting its position as your braze around the minor tube because it is hot and you have to have something to help you move it. If you have one long tube (maybe starting out as 2 feet long) and then a mitered stub on the end, you can use your bare hand to reposition it as go. And you don't lose much length when you cut the braze off of the end. It is also more realistic to how you would hold a frame. By the way I use wood blocks to hold my tubes or frames for brazing because they have just the right amount of stickiness to slipperiness to move and hold the work. It is easy to melt the rubber protectors in Park jaws.

    I understand how challenging it can be for a family man to get away for either my 2 week or more common 3 week class. Once a year I offer a 3 day Intro class. I might even do a 1 day class. We'll see. What I know is that beginners vastly shorten their learning curve with experienced instruction. It gives them a huge competitive advantage over the DIY types.

  8. #8
    shifty
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    Quote Originally Posted by doug fattic View Post
    I understand how challenging it can be for a family man to get away for either my 2 week or more common 3 week class. Once a year I offer a 3 day Intro class. I might even do a 1 day class. We'll see. What I know is that beginners vastly shorten their learning curve with experienced instruction. It gives them a huge competitive advantage over the DIY types.
    I took doug's 3 day class. It was a perfect fit for me. I'm in the western burbs of chicago if you want to chat sometime. I'm no expert, but on frame #8 so I've made plenty of mistakes that i can share with you...

    -Bernie

  9. #9
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    FYI, scrap HT tubing is no fun to miter versus 4130. For that reason alone, I'd consider spending some money on 4130 sections. 4130 isn't expensive at all really. Shipping is what gets expensive with tubing IMHO. For $50, you can have have a pretty nice pile of practice parts from Aircraft Spruce. YMMV.

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