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Thread: Duct Hunter

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    Default Duct Hunter

    I am having problems. Just today, I pushed my rodder into some cast iron and couldn't find it under the concrete. It was a time sensitive job and it was my last locate. I located 300' length and 10'+ outside with no problems with 83KHZ 10mA. I was trying to use my camera to see what may be wrong while locating the pipes but I couldn't get out far enough. Then on the pull out I skinned my Kevlar coated line! I should not have run it out once I realized the condensation didn't allow me to see but I allowed them to push me and did it anyway. Any thoughts for a better locate?

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    Mke
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    Default Re: Duct Hunter

    I'm a bit confused on the details. Did you have a sonde in the pipe at all? Or were you just trying to locate the Rodder and wire?

    I have used a Sonde to locate in Cast before, it is difficult and really depends on depth and frequency used. As for the Rodder and wire.... I've done this with my 810 before, but you get mixed results depending on how reinforced the concrete is. I've been in the middle of our Terminal looking for a 4" cast sewer, and was not able to find it with a rodder and wire... Only a Sonde.

    I can't remember, what equipment are you using again?

    mke

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    Default Re: Duct Hunter

    I tried using my sewer camera which does have a sonde and three frequencies 33, 512, and whatever they use in Europe that is very close to 512. I was using 512 with good results under the concrete until I got hung. That is when I went back to the Duct Hunter that I used in the grassy areas outside. I really need a sonde on a duct hunter but I cannot find a strength and size that I want. I am using a Vivax vLocPro.

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    Conservative Meanie ifinditunderground's Avatar
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    Default Re: Duct Hunter

    I already addressed this in your thread on locating cast iron sewer mains:

    "There isn't much you can do unless you can hook directly to the pipe, or induce a signal onto the pipe from the surface. When you insert fishtapes or sondes into metallic pipes you more often than not will get a cancelling of that signal. I believe it's called "Gauss Theory", or something similar."

    You cannot insert tracing wires into cast iron mains, it does not work. Based on the posts of others, my statement was not entirely true, as others have had luck in locating with sondes inside metallic mains. But the tracing wires stands true.
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    Default Re: Duct Hunter

    Quote Originally Posted by ifinditunderground View Post
    I already addressed this in your thread on locating cast iron sewer mains:

    "There isn't much you can do unless you can hook directly to the pipe, or induce a signal onto the pipe from the surface. When you insert fishtapes or sondes into metallic pipes you more often than not will get a cancelling of that signal. I believe it's called "Gauss Theory", or something similar."

    You cannot insert tracing wires into cast iron mains, it does not work. Based on the posts of others, my statement was not entirely true, as others have had luck in locating with sondes inside metallic mains. But the tracing wires stands true.
    You are right and I remember, you did answer the question on cast. I suppose I should have asked this....When dealing with a hodgepodge plumbing mess, what other tools do you guys use to compliment a transmitter, receiver, and rodder since I will not want to use my camera to locate an area I cannot see. To be honest locating with a camera seems to be the last thing I want to do with a camera if it is the only purpose to which I was called out. I was just frustrated with the job.

    Thanks for the replies.

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    Mke
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    Default Re: Duct Hunter

    Hey Getinit, The locate bible specifically says to "try everything". Just because it doesn't work one time, doesn't mean it won't work the next. Even the Rodder with tracerwire in a cast iron pipe.... most the time you will be beating your head against the wall.... but every now and then it will light up a signal that can be marked.

    As for not using your camera to locate..... I wouldn't say to use it first, but I think the camera with sonde is extremely important to use. you do have to be cautious about not getting it stuck or damaging the cord, but not to affraid about shoving it in random holes. (Feel free to take that last part out of context)

    Mke

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    Default Re: Duct Hunter

    I have no idea about this but it makes me think about GPS. I wonder how accurate GPS is and if there will come a time where you could fish a real small GPS through the pipe and when you pull it back out it would have tracked the pipe and you could then retrace the steps of the GPS above ground. I guess it's probably just a pipe dream(pun intended) but it seems feasable.

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    Default Re: Duct Hunter

    Quote Originally Posted by Mke View Post
    Hey Getinit, The locate bible specifically says to "try everything". Just because it doesn't work one time, doesn't mean it won't work the next. Even the Rodder with tracerwire in a cast iron pipe.... most the time you will be beating your head against the wall.... but every now and then it will light up a signal that can be marked.

    As for not using your camera to locate..... I wouldn't say to use it first, but I think the camera with sonde is extremely important to use. you do have to be cautious about not getting it stuck or damaging the cord, but not to affraid about shoving it in random holes. (Feel free to take that last part out of context)

    Mke
    Where is the like button?....LMAO

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    Default Re: Duct Hunter

    Quote Originally Posted by Goldenboy View Post
    I have no idea about this but it makes me think about GPS. I wonder how accurate GPS is and if there will come a time where you could fish a real small GPS through the pipe and when you pull it back out it would have tracked the pipe and you could then retrace the steps of the GPS above ground. I guess it's probably just a pipe dream(pun intended) but it seems feasable.
    Well the way technology has come maybe, I suppose. They are almost dead on as far as the ones surveyors use. Seems like I loose GPS every time I go through a tunnel or down the street though, lol.

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    Mke
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    Default Re: Duct Hunter

    my company has a few R8 units from Trimble.... some of the best GPS gear out there. I think GPS will be a player in the locating game soon enough, but not the way you are describing. First off, As expensive as the antennas are... you deffinately don't want to be putting them down any pipes. Second, even with using the GLONASS satellites you have to have a constant radio link with the base stations and the data collector, as well as a connection with the satellites. You still can't get too close to buildings, Trees, Overpasses etc...

    Where GPS will come in....

    When Utility companies realize that most construction utilizes surveyors with GPS equipment that can get to tolerances of .01 of a foot they will start to record all of the new utilities being installed (Like we do) and surveyors will be able to get within that legal tolerances of locates. As of right now, my company GPS's all new utilities, and GPS's all potholes of existing utilities. Soon enough they can design projects without survey locates and start construction and use their onsite surveyors to locate utilities.


    Mke

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