Notifications
Clear all

Why are we still in the dark ages

7 Posts
4 Users
0 Reactions
5 Views
(@nate-the-surveyor)
Posts: 10522
Registered
Topic starter
 

With metal detectors?

I bought a small handheld one, it detects aluminum, and other metals.

Here are some instances where multiple metal would be useful:

Finding aluminum nails In trees, (witness trees, with aluminum nailsl) where the tree has grown over the nails.

Finding aluminum survey marks. Sometimes the magnet in the base is gone.

Some surveyors set non iron survey marks.

I'd like them to detect a broader range of metal. Aluminum, copper, and such.

I recently heard of a surveyor that set loads of aluminum pipes.

It's time to move beyond iron only detection.

N

 
Posted : May 12, 2020 3:02 pm
(@richard-imrie)
Posts: 2207
Registered
 

I thought the cheapest detectors (i.e. the one I have) detected all metals? Hence when we look for a "iron rod" we typical find everything - beer cans, coins, chocolate bar foil wrappers, mobile phones (dug up three so far), the lining inside cigarette packets ...

 
Posted : May 12, 2020 3:12 pm
(@a-harris)
Posts: 8761
 

I have set lightweight aluminum conduit or pipe and stainless steel over rebar set in wetlands for an object that would not rust away and would hold the steel remains inside for a Schonstedth to find later.

0.02

 
Posted : May 12, 2020 3:13 pm
(@bill93)
Posts: 9834
 

Most metal detectors that are not magnetic locators respond to the product of the metal's conductivity and the surface area presented to the detector coil, and inversely with the distance. There are some variations in treasure hunter designs that alter that but only a little, and some have smarts to do a better job of recognizing changes from the soil to a metal object.?ÿ Those generally rely on steady movement of the coil to recognize a sharp change.?ÿ

A pop top may show up as strong as a vertical aluminum pipe if only the end is presented to the coil.

The conductivity of common metals in decreasing order is silver, copper, gold, aluminum, ..., brass, zinc, ..., iron.?ÿ

So with iron so far down the list, you definitely want the magnetic locator for it if the object has any length to it.

If you are looking for a bronze or aluminum cap, a treasure hunter type is quite useful. I wouldn't go hunting one without my detector.

 
Posted : May 12, 2020 3:22 pm
(@richard-imrie)
Posts: 2207
Registered
 

@bill93

So, "pin-finders" of the Schonstedt type, are actually magnetic field detectors?

 
Posted : May 12, 2020 3:50 pm
(@bill93)
Posts: 9834
 
Posted by: @richard-imrie

So, "pin-finders" of the Schonstedt type, are actually magnetic field detectors?

Yes.?ÿ They work on the principle of a magnetometer.?ÿ The Schoenstedt has two sensors spaced 15 or 18 inches apart in the pipe and it reads the difference in magnetic field for those two locations.?ÿ Take a screwdriver or nail and run it up the pipe to see where.

Iron will "suck in" the earth's magnetic field (soft iron effect) and/or have its own permanent field, so the difference grows stronger when nearer the iron.

?ÿ

 
Posted : May 12, 2020 4:01 pm
(@nate-the-surveyor)
Posts: 10522
Registered
Topic starter
 

I can imagine a shonstedt, with a piggy back aluminum, gold, silver detector. Ya never know... Ya might find a pot-o-gold, and retire, if you had more than an iron detector!

 
Posted : May 12, 2020 4:35 pm