Detector for a Surveyor

[Scratchysack]

Hey everyone,

I'm new to the metal detecting world, so I need some advice. I am a surveyor, and am looking for a detector that can find survey marks that are placed underground efficiently and with little to no metal detecting knowledge.

I'm looking for something that will detect galvanised iron pipes, that are driven into the ground in an upright position. They are around 1" - 40mm in diameter and are usually only 100mm below the surface, but can be 500mm deep at times.

It would also be useful if it could detect bronze and be able to sweep rather than pinpoint. Light and compact are also preferred.

Any thoughts or recommendations?

Thanks,

Mick.

 

[Jaros]

Welcome to P.A.Mick. You might hire a few of the top end Detectors and take your pick.

 

[Balmain Bob]

Hi Mick
I recon a Minelab Go-Find 66 would suit for most of the situations as you state that the targets are generally 100m deep at most. Its a good basic detector, not dificult to use. If your looking to do a bit of relic/ treasure hunting then on of the Equinox machines would suit.
https://go-find.minelab.com/en/products/go-find-66https://www.minelab.com/metal-detectors/equinox-800To detect down to the 500mm mark you are looking at big $$ for a GPZ 7000
If your not going to hunt for gold then a top end detector would be a waste of money
Cheers
Bob

 

[user 4386]

Hi Mick
I recon a Minelab Go-Find 66 would suit for most of the situations as you state that the targets are generally 100m deep at most. Its a good basic detector, not dificult to use. If your looking to do a bit of relic/ treasure hunting then on of the Equinox machines would suit.
https://go-find.minelab.com/en/products/go-find-66https://www.minelab.com/metal-detectors/equinox-800To detect down to the 500mm mark you are looking at big $$ for a GPZ 7000
If your not going to hunt for gold then a top end detector would be a waste of money
Cheers
Bob

I would have thought that if they are 40 mm pipes driven vertically, that is a fair mass of metal even at 500 mm depth, so perhaps not so expensive, So perhaps hire a cheapy and try it.

 

[grubstake]

Metal detectors don't react to target mass, it's surface area that counts for the eddy currents they create in a metal target. A vertical pipe only has a very small surface area at the top, the remainder goes increasingly deeper and may not present much of a target. A big coil would help greatly in this respect.

 

[Jaros]

Are you saying none of your fellow surveyors can assist in your task??

 

[EVIE/BEE]

A good cheap SD2200D would be ideal for this at around $800 to $1000.

 

[aussiefarmer]

Powerlines , phone lines , electric fences, and every metal item will have you sqeaking and sqaurking.
Not saying don't get one just realise they won't be the answer in every location.

What is the go to method for locating them ?
Go to a good prospecting shop , explain the mission and then will more than likely take 2 or 3 machines to the nearest marker for a trial.

 

[Scratchysack]

Hi Mick
I recon a Minelab Go-Find 66 would suit for most of the situations as you state that the targets are generally 100m deep at most. Its a good basic detector, not dificult to use. If your looking to do a bit of relic/ treasure hunting then on of the Equinox machines would suit.
https://go-find.minelab.com/en/products/go-find-66https://www.minelab.com/metal-detectors/equinox-800To detect down to the 500mm mark you are looking at big $$ for a GPZ 7000
If your not going to hunt for gold then a top end detector would be a waste of money
Cheers
Bob

Thanks Bob, this exactly the sort of advice I was looking for.

 

[Scratchysack]

Powerlines , phone lines , electric fences, and every metal item will have you sqeaking and sqaurking.
Not saying don't get one just realise they won't be the answer in every location.

What is the go to method for locating them ?
Go to a good prospecting shop , explain the mission and then will more than likely take 2 or 3 machines to the nearest marker for a trial.

The goto method for locating them is just estimate where they should be based off the plan (with no depth indicated), then just start digging until you choose to give up. It's a time consuming - and often fruitless - exercise.

 

[Scratchysack]

A good cheap SD2200D would be ideal for this at around $800 to $1000.

Thank you Evie

 

[Hawkear]

A lot of the top detectors have a problem with emr interference in built up areas so that would be a problem with the SD, GP series. A VLF may be a better choice.

 

[Redfin]

Yes,. VLF much more suitable, cheaper, lighter and much less bulky.

 

[user 4386]

Metal detectors don't react to target mass, it's surface area that counts for the eddy currents they create in a metal target. A vertical pipe only has a very small surface area at the top, the remainder goes increasingly deeper and may not present much of a target. A big coil would help greatly in this respect.

I assumed that a pipe driven into the ground has a significant plan area (it would not be sheet metal) - so that the magnitude of signal would not be too much of an issue at such depths - and wouldn't the actual diameter of the pipe be a major factor in the area of the secondary field produced in the buried object? It is a long time since I did electrical engineering at uni but I thought the vertical extent of pipe would affect the area of the resulting surface anomaly, making it easier to detect. However I guess it all depends primarily in having a strong enough secondary field to start with, to distort the primary field sufficiently to detect that distortion, but I'm obviously out of my depth (pun). I guess a vertical pipe would produce a horizontal secondary field more parallel to the field doing the induction and producing less vertical component in distorting the field? Whereas a horizontal conductor would produce a greater vertical secondary field component for the detector to detect?????

 

[bicter]

If you're trying to locate your target in benign ground in electrically noisy locations such as urban areas, a good VLF detector would be my choice but once the ground starts to become mineralised then a PI will improve the chances of locating the target, especially if in an electrically quiet area.

 

[Gold1hunter]

Just buy a minelab go find 66 they're only $400 from Anaconda and often have a 20% off sale, get one second hand for around $250. It'll probably do the job and if it doesn't you can always stick it on Gumtree. The 66 folds up very small, won't take up room in the car is light & easy to use. You can even get an app for it & can listen to music via Bluetooth from your phone and target signals will come in over the top.
I don't own one as I went a bit more up market (equinox 800(parks & beaches) and Gpz7000 (gold)) but for what you want the 66 is worth a try.

 

[Phil8303]

Hey everyone,

I'm new to the metal detecting world, so I need some advice. I am a surveyor, and am looking for a detector that can find survey marks that are placed underground efficiently and with little to no metal detecting knowledge.

I'm looking for something that will detect galvanised iron pipes, that are driven into the ground in an upright position. They are around 1" - 40mm in diameter and are usually only 100mm below the surface, but can be 500mm deep at times.

It would also be useful if it could detect bronze and be able to sweep rather than pinpoint. Light and compact are also preferred.

Any thoughts or recommendations?

Thanks,

Mick.

(Not a serious reply, but...) if work is paying get an SDC2300. Then you can use it on weekend trips as well!

 

[Gold1hunter]

Anna

Just buy a minelab go find 66 they're only $400 from Anaconda and often have a 20% off sale, get one second hand for around $250. It'll probably do the job and if it doesn't you can always stick it on Gumtree. The 66 folds up very small, won't take up room in the car is light & easy to use. You can even get an app for it & can listen to music via Bluetooth from your phone and target signals will come in over the top.
I don't own one as I went a bit more up market (equinox 800(parks & beaches) and Gpz7000 (gold)) but for what you want the 66 is worth a try.

Anaconda has Easter sale on detectors now! you can buy one (go find 66) for $319