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Dead Rebar  

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John Thompson
(@john-thompson)
20+ posts Registered

Found this yesterday.
[MEDIA=youtube]0VkPO6AWoII[/MEDIA]

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Posted : March 18, 2017 7:45 am
flyin solo
(@flyin-solo)
500+ posts Registered

i wouldn't call that "dead." Dying, perhaps, but still sounds like a "dig here" to me.

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Posted : March 18, 2017 7:51 am
Steve Hankins
(@steve-hankins)
5+ posts Registered

John Thompson, post: 419063, member: 9631 wrote: Found this yesterday.
[MEDIA=youtube]0VkPO6AWoII[/MEDIA]

Maybe touch the top portion of the dead rebar with a magnet.

Steve Hankins
Hankins Surveying
Hot Springs, Arkansas

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Posted : March 18, 2017 7:59 am
Nate The Surveyor
(@nate-the-surveyor)
5,000+ posts Registered

It's got a null at the end. Go slow.
Somebody may have pounded the magnetism out of it.
N

Surveying is more than a Job----it is a passion to provide a foundation for future generation, that is beyond reproach.

Nate

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Posted : March 18, 2017 8:04 am
Sergeant Schultz
(@sergeant-schultz)
500+ posts Registered

I've dug at many a null signal and found something, but usually only after pulling in a distance or two to narrow the search radius.

Zwei weitere Biere, bitte

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Posted : March 18, 2017 8:29 am
billvhill
(@billvhill)
250+ posts Registered

The scary thing about this is, it makes you wonder how many times you could have missed something. I worked on a job this week where I had this issue. I searched all morning and was almost convinced that nothing had been set. There was a railroad near by which had a curve about a half mile away. I ended up locating the tracks and calculating the pc and pt. I finally found something and was able to backtrack from there. When I started recovering corners, I almost had to be on top of them to pick them up. The monuments were capped 5/8" rebars about 18" long set in seventies.

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Posted : March 18, 2017 8:57 am
holy cow
(@holy-cow)
10,000+ posts Registered

I don't know about everyone else's case, but when the video is over for me two other potential videos appear to be selected. The one on the right is a banned scene from a Tarzan movie made in 1934. My, oh my !

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Posted : March 18, 2017 8:57 am
holy cow
(@holy-cow)
10,000+ posts Registered

This thread follows directly in line with the story I told here a couple of days ago about dead bars set by the DOT with about two inches of asphalt overlay over them.

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Posted : March 18, 2017 8:59 am
Shawn Billings
(@shawn-billings)
1,000+ posts Registered

Always a good idea to do a little digging before you set a monument (unless you are the original surveyor, in which case it doesn't really matter). I don't want to someday find one of my capped rods to be 0.2' from an original rod that's buried a few inches below grade.

Shawn Billings, RPLS
Owner of Pendulum Surveying in East Texas
I also provide sales, support and training for Javad Triumph-LS RTK Systems

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Posted : March 18, 2017 9:06 am
Mark Mayer
(@mark-mayer)
1,000+ posts Registered

Many a time I have watched a supposedly experienced person use the Scheonny poorly. It's kind of a thing with me. Waving it around too fast, swinging it around such that the height above ground of the sensors is all over the place, not systematically covering an area. Every unit comes with a little instruction booklet which aught to be read, comprehended, and followed. There is a science to the use of the pin finder which few users seem to comprehend. It's almost like a guy should have to get a certificate of competency on the thing before being allowed to use it. (The guy in the video is using the unit reasonably well and, after all, he has found the buried "dead rebar" one way or another)

The geologic history of Oregon has included numerous basaltic lava flows and basalt is a rock with a high iron content. As such a lot of times the pin finder rings for ordinary field rocks around here. That, together with the usual metallic garbage that accumulates around property corners, renders the Sheonstedt only search success rate somewhat lower than 100% even when used correctly.

Most survey crew members seem to think of waving the pin finder around as the beginning and end of a pin search. I tell guys that before they even turn the thing on they should go through a checklist in their minds. Occupation lines? Bits of flagging or old lath? Evidence of digging by surveyors past? Location of previously found irons relative to road and curb lines? Look first, really look. This is the "art" part of the pin search. Then, and only then, go to buzzing. After you are done buzzing look again before abandoning the search.

Then you really can't declare a point lost until it's been staked out and the position dug regardless of whether it buzzes or not. Sometimes bars don't ring.

EDUCATION, n. That which discloses to the wise and disguises from the foolish their lack of understanding.

EXPERIENCE, n. The wisdom that enables us to recognize as an undesirable old acquaintance the folly that we have already embraced.

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Posted : March 18, 2017 9:21 am
Tyler Parsons
(@tyler-parsons)
500+ posts Registered

I have one of the indicating Schoenstedts GA-72. Most in-place monuments show indication to the right side. When I buy new rebar, I test each with the pin finder to see if they have a strong mag field. If not, I touch a very strong magnet to one end and usually give them a hammar tap at the same time. I paint the end that gives a right indication red and that gets set for the top.

I usually throw my 60d coontrol spikes in a bin with the same magnet for a while. It makes them much easier to find weeks or years later.

Also, waving the strong magnet over the area you are searching can sometimes induce enough magnetism to make the monument visible to the pinfinder. Doesn't go too deep though.

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Posted : March 18, 2017 9:30 am
Mark Mayer
(@mark-mayer)
1,000+ posts Registered

Holy Cow, post: 419072, member: 50 wrote: I don't know about everyone else's case, but when the video is over for me two other potential videos appear to be selected. The one on the right is a banned scene from a Tarzan movie made in 1934. My, oh my !

TMI. Those are personalized based on your Youtube viewing habits. My, oh my indeed.

EDUCATION, n. That which discloses to the wise and disguises from the foolish their lack of understanding.

EXPERIENCE, n. The wisdom that enables us to recognize as an undesirable old acquaintance the folly that we have already embraced.

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Posted : March 18, 2017 9:31 am
Shawn Billings
(@shawn-billings)
1,000+ posts Registered

Mark Mayer, post: 419077, member: 424 wrote: Look first, really look. This is the "art" part of the pin search.

I don't know how often this happens by percentages, but it's a lot. I turn on the locator and start sweeping. I'm looking where I'm sweeping and I see the stake, or evidence of the stake, before I pick up a signal, because at the same time I'm sweeping with the locator, I'm also sweeping very intently with my eyes ("really looking"). The stake itself, some bit of color from old ribbon, a piece of an old wood stake, a depression from previous excavation, etc.

Shawn Billings, RPLS
Owner of Pendulum Surveying in East Texas
I also provide sales, support and training for Javad Triumph-LS RTK Systems

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Posted : March 18, 2017 9:32 am
Mark Mayer
(@mark-mayer)
1,000+ posts Registered

Shawn Billings, post: 419075, member: 6521 wrote: Always a good idea to do a little digging before you set a monument. I don't want to someday find one of my capped rods to be 0.2' from an original rod that's buried a few inches below grade.

For me that comes under the heading of staking the point out and digging, regardless of pin finder response, before declaring the corner lost.

EDUCATION, n. That which discloses to the wise and disguises from the foolish their lack of understanding.

EXPERIENCE, n. The wisdom that enables us to recognize as an undesirable old acquaintance the folly that we have already embraced.

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Posted : March 18, 2017 9:35 am
Shawn Billings
(@shawn-billings)
1,000+ posts Registered

If the guy in the video slowed down a bit over the dead rod, he probably would have noticed that the locator buzzes a little when off the rebar and goes almost silent when over the rebar. It still gives a tonal notice that there is a "disturbance in the force", just not the squeal one would normally expect.

Shawn Billings, RPLS
Owner of Pendulum Surveying in East Texas
I also provide sales, support and training for Javad Triumph-LS RTK Systems

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Posted : March 18, 2017 9:36 am
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