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  1. #1
    The cat's name is jake
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    Seatstay TIG welding

    In an earlier thread, people were talking about dealing with TIG welding seatstay/seat tube clusters. I thought I'd take some photos of how I weld these areas, in case it is helpful to someone struggling with this part of the frame.

    I start by placing a puddle of material that bridges both seatstays, and the seat tube. I place this puddle such that it forms an elevated platform that is higher than the true root of the 3 tubes.
    Seatstay TIG welding-seatstay-welding-1.jpg

    After that, I'll wrap from the inside, out around the bottom of the seatstays to the sides of the seatstays/seat tube.Seatstay TIG welding-seatstay-welding-2.jpgSeatstay TIG welding-seatstay-welding-4.jpg

    continued on the next post.

  2. #2
    The cat's name is jake
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    At this point, if things are looking too warm, I might move on to another section of the frame. Typically, I move fast, so things aren't too hot, and I'll continue welding around the seatstays from the bottom to the top, until the 2 welds join again at the top.
    Seatstay TIG welding-seatstay-welding-5.jpg

    This is a really good time to move elsewhere, unless you are dealing with thicker tubing. In this case, the seatstays are .6mm or less, so I'll go weld near the BB or the HT for a short time, then come back.

    Once I've come back, I'll start zippering the central area up. If possible, I like to either end a little above the tight space where the weld comes between the seatstays, or in the central "pad" where I started from. In this case, I chose to end above the tight space, so I welded down from the top, then started at the pad and brought the weld out to meet the central weld.

    Seatstay TIG welding-seatstay-welding-6.jpg

    Voila! Piece of cake.

    Here's a couple more photos, while I have the camera out.
    Seatstay TIG welding-peter-bungum-2.jpg
    (Peter Olaf Bungum)
    Seatstay TIG welding-peter-bungum-1.jpg
    (Peter Olaf Bungum)

    P.s. Amperage = 120 a, pulse 1.8pps, on 28%, background 5%.

    Good luck, ladies and gentleman, you CAN do it!
    Last edited by BungedUP; 03-01-2014 at 03:02 PM.

  3. #3
    J_K
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    Quote Originally Posted by BungedUP View Post

    Voila! Piece of cake.
    That sums it up!
    Just amazing.

    That's undoable for me, at least anything under .035"

  4. #4
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    Wow, that's sweet!
    Mark Farnsworth, Raleigh, NC
    http://farnsworthbikes.com

  5. #5
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    Awesome- This one is bookmarked for when I get there. Thanks for the clear explanation on a part I am kind of dreading!

  6. #6
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    Beautiful!!!

  7. #7
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    Thank you for sharing! Very helpful and about the hardest to do weld.
    I notice the heatsink which I think is a big help.
    Good point on waiting for the heat to let off, I get impatient sometimes.
    And thanks for ALL the numbers!!! I have been doing 30%on and 15% background, I will try that lower background.
    Do you use different background settings on other welds like the headtube/downtube?
    thanks
    andy walker
    Walker Bicycle Company | | Walker Bicycle Company

  8. #8
    Nemophilist
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    As always;

    Priceless content. Thanks, Professor!
    Most people ply the Well Trodden Path. A few seek a different way, and leave a Trail behind.
    - John Hajny, a.k.a. TrailMaker

  9. #9
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    Seatstay TIG welding

    Beautiful work and thanks for the tips!
    It looks like the backs of the stays are welded together and not fully to the seat tube, similar to the DT/ST joint?

    The biggest problem I have is getting the torch head positioned and seeing the area clearly when the miter angle is so steep. Welding by brail.
    Do you use a smaller cup size or pencil torch?

  10. #10
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    Awesome. Where were you in 2003 when I was blowing holes in what felt like a hundred consecutive seatstays trying to figure this out?!?

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

  11. #11
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    Thanks for the insight!

  12. #12
    RCP Fabrication
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    Is that er70 I see there? s2 or s6? I am about done with 880T when I finish up the 3 pounds I have left.

  13. #13
    The cat's name is jake
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    Well good! Sounds like it may be of some help. I was actually thinking of you, thedudeman when I took the pictures (though also that it might help others too).

    Andy - I do change things, depending on what I'm doing. Keep in mind that I come across a lot of different stuff in any given day - touring tandems, race tandems, race singles, touring singles, triples, quads, quints, 29'ers, 26ers, bikes for other companies under contract with the company I work for, aluminum frames, stainless steel parts, stems, etc. I largely keep with the same philosophy for steel frames though - keep the heat down as much as I can, by melting fast, then moving. On a typical single bike, I'd keep those same settings, except I'd boost the total amperage to 130+ on BB areas, dropouts, etc.

    Meriwether - You have it right. It's just not safe to weld down to the seat tube, as I often need to grind the sides of the seatstays to get them to sit properly on the seat tube itself (due to interference). I have only moderate eyesight anyway, so I never see anything all that well. I do often weld around corners I can't see, but I can usually get a decent line of sight in the seatstay area. Partially, by starting at the bottom and working out, it helps with that. Sometimes, You can weld the inside portion of the seatstay that is across from you, with the filler rod reached around the seat stays (hard to describe). By that I mean the first side you weld with filler toward you (coming out, welding from inside bottom with frame upside-down), then start in the middle pad again and welding out away from you, with the frame in the same orientation (does that make ANY sense?). It can help with visibility. I don't use a pencil torch - just the same WP-20 I always use, with a #6 cup. By welding down the seatstay until it opens up enough to transition the torch around, you don't really need anything else to do it. Soemtimes the tungsten gets run out a ways, but it's never too bad unless you are trying to do that AND weld past an apex (which blocks gas flow).

    Walt - Ha! You were way ahead of me in 2003 - I was probably still welding truck beds, and teaching community college biology classes up and down the Willamette Valley. I was trying to figure out how to MIG weld in a garage where the electricity was actually hooked up to my neighbors place (unbeknownst to me for awhile). I kept taking the power out, then fiddling around with my fuse box in the apartment, trying to figure out how to get the power back. I'd go back down to the garage, and magically the power would be back, but it took me awhile to realize that it was because the neighbors had to flip THEIR breaker! Yeesh - it's embarassing to think about how dumb I was sometimes back then. I'm probably even dumber now, but at least I'm willing to recognize it.

  14. #14
    The cat's name is jake
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    Quote Originally Posted by RCP FAB View Post
    Is that er70 I see there? s2 or s6? I am about done with 880T when I finish up the 3 pounds I have left.
    That was ER70S-2, but good stuff. I also use ER70s-6 at times, and also I have used some 880T more recently. Good ER70S-2 is GREAT. BUT, there is a lot of variation in ER70s-2, so it can also be just terrible to use. I'm in the process of compiling some information about that, which I'll share when I have a whole article about it.

  15. #15
    RCP Fabrication
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    Theres nothing wrong with 880. I love it for mixed metals, stainless dropouts, etc. What brand er70 is your favorite?

  16. #16
    The cat's name is jake
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    I think that 880 (or 312) has some VERY desireable qualities, especially in tight joints where undercutting is typically prone. You are right about dissimilar metals as well - it seems much better than 309L for those purposes. I don't prefer it to good er70s-2 in other areas though, although my coworker I think does prefer it universally (goes to show that personal preference has a lot to do with such things).

    As far as ER70S-2 are concerned, it isn't brand that is important, as they seem to all source wire from different places. It is country of origin that seems to make the biggest difference. Korean wire tends to have the most consistent properties, and when dealing with tubing from Reynolds or Fairing, it hides the "crusting" that those tubing products tend to exhibit. Wire from Turkey, Italy, and other places varies, such that sometimes they are ok, and other times they are quite bad.

    I have found another source that draws and cuts wire for TIG welding purposes, and has certs to verify it's content. The sample I received from them was EXCELLENT, and at a good price (less than $7 per pound). I haven't bought more material from them yet, but plan to do so personally, as well as trying to get the shop I work for to start using it, as consistency of filler has been a real issue for us. This same place also sells 312 for an EXTREMELY good price. Again, I can post more information later on.

  17. #17
    RCP Fabrication
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    Mind sending me some information on that place? I am getting ready to place an order of filler.

    Also, I have always known weldmold 880 to be SIMILAR to ER312L. Did weldmold say it is a 312 filler or it IS ER312L? (this is just something I'm curious about, has nothing to do with frames)

    Thanks

  18. #18
    The cat's name is jake
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    RCPFAB - I am happy to disclose information on welding supplies, technique, etc., to anyone, assuming I feel halfway confident in the quality of the information, and I feel it won't get me into trouble!

    The recent samples have come from Global Laser Tek. The man to contact is Dan Polto - I think they are in Ohio. They specialize in welding wire in small diameters, but Dan has been able to produce some .045" wire for us. I think they work in the 10# quantities. Maybe they'll do smaller, but I am not confident in that.

    As to the 312 question - that I don't know at the current time. If/when I find out more, I'll pipe up when I remember to. I haven't run into 312L, or at least that I noticed.

  19. #19
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    Welder Setting

    Thanks for the info mate,
    Just a couple of questions about your setting if it is OK.

    1. Amperage, I take it 120 is the peak?
    That seams to put your average around 35, which seems normalish to me, but if 120 is your average, your peak must be up near 300 at least. gotta be a heavy duty 3 phase machine. I weld 2" sch40 butts on that, and I weld hot??

    2. Your pulse setting?
    Is such a heavy pulse common in the bike industry, I commonly run around 60/30. But that is coming from a pipe background. I guess the heavy pulse restricts your penetration but gives the wide well defined stack of coins? also helping control blowing holes?

    Thanks for your time.

    PS
    I am finally building my flex plate Ti dually this week. photos next week.

  20. #20
    The cat's name is jake
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    Hi Crispy,

    I am currently using a Dynasty 200 DX, and the 120 amps is "peak" amperage as set per the main amperage control knob. On a Dynasty, seeing the actual amperage is near impossible for me - it seems to jump all over the place. Analog meters like on my CP300 MIG machine are much nicer for viewing actual amps.

    I don't think that this style of pulse is common, but that is based on seeing what other welders at just 2 shops are using. I initially learned using 60/40, but after spending a lot of time fiddling, and thinking about what I was doing, I eventually settled on this style for thin-walled tubing, common to single bikes. I have suggested this style to a few other professional welders, and all have been fairly tickled with the results.

    On tandems/triple/+ frames, I use more amps yet, and sometimes with different background and peak periods, but the same idea - a big blast, followed by a "resting period". You might be familiar with titanium pipe welding techniques - I believe that this is most similar to that, though I understand that to have an even longer rest period, at least the way that some do it.

  21. #21
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    I think I spot a Miller Dynasty DX 200 in one of those pics, so no the peak is not 300.
    The pulse of 1.8 per second is not so much. 30 pulses per second or 60 or 150 is starting to be alot, but 1.8 not so much I think. I often do 1 pps and that gives a nice metronome like rhythm, and 1.8 is good too as you get used to the dabbing of the filler. You can go a little hotter at 1.8 pps I think and move quicker
    cheers
    andy walker

  22. #22
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    There's not really an average amperage 2 pulses per second. Its a more defined high/low.

    When you get to 30 pps and higher you will start needing more amperage than you would with out pulse.

    Everything between 2 and 30 pps will cause your brain to melt.

  23. #23
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    So I'm usually a no-pulsing old school kind of stick-in-the-mud... and I tried these settings and they're pretty great. Welds very nicely indeed but damned if I can see what the hell is going on. Pete, do you have any tips there? I'm not on any kind of fancy autodark silliness, just your basic flip-down hood and I've got no problems when foot pulsing or just welding entirely manually.

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

  24. #24
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    i'd love to hear too BungedUp.
    I just switched a couple of frames ago to pulsing and even though it's going pretty well, i feel like i'm using the Force, especially in the acute angled tight spots.
    A slower PPS helps keep track of where you're going (say...1.5 instead of 2pps). On my hood i have it set at the 9 shade so if you're using a darker lens on your non-auto hood maybe a lighter one will help?

  25. #25
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    Am I the only person who uses high speed pulse?

    150 amps
    50 pulses per second
    33% on time
    33% background

    I still have a hard time giving up the control, and the benefits of high speed pulse

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