Metal Detectors In Winter

[+BilboB]

I have been using my metal detector for some of the trickier finds and it has proved indispensable. Now it has started to snow in Vermont and with the onset of Winter, snow is on the ground and will probably be here till April, making it much more difficult to locate benchmarks.

 

My 3 questions are these:

 

1. Do metal detectors work through snow? about how deep?

2. Do metal detectors work through ice? about how thick?

3. Anyone have problems with their detectors in cold weather?

 

I made some feeble attempts at locating some benchmarks today, but I forgot the detector at home, and the 4 inches of slush everywhere and even deeper by the roadside made me think of these questions.

[+ddnutzy]

I have found quite a few bm's through the snow with my metal detector. The disks on my white are waterproof so the snow has never bothered the unit. Ice has not been a problem either. It has worked at seven below zero with no trouble.

[+PFF]

Batteries are adversely affected by a cold operating environment. Consider keeping the batteries in an inside jacket pocket, warm automobile, or thermal bag until needed.

 

It would be a good practice to avoid leaving the unit in your car overnight, prior to a day of hunting. And when you bring it out of the warm house, keep it inside the car, rather than in the trunk.

 

Ditto for your camera. And not just because of the batteries. Extreme cold can damage LCD displays.

 

Of course, you could simply move South. Did I mention I'm in real estate? Here's my card......

 

-Paul-

(Raleigh, NC)

[+zygote2k]

I use a survey-grade metal detector year round and snow, water, and ice seem to have no effect on detection. It really depends on the quality of your detector.

[+BilboB]

Thanks to all for the good information. My detector is of pretty-good quality, so I am going to put it to the test tomorrow AM when I go out (day off of work, so I have to make some good use of it). I was looking more into specific depths of snow and ice, not just if it works or not. Good info on the batteries in the unit as well. Had not thought of that.

[evenfall]

Bilbo,

 

One of the things I find interesting is that you have likely asked a question that has quite frankly never been tested, and even if tested would likely only apply most specifically to your make and model of detector.

 

I would like to propose a test. I would take an aluminum pop can, a steel soup can, a chunk of steel say of railroad spike size, and perhaps another a little larger, and if you like, add some other interesting items, including say change or other small items you feel would be commonly found when using a detector.

 

Begin this test in your driveway. Just lay them out and see what the distance above the items is when you begin to detect them. What is the signal strength at say 18 inches, a foot, 6 inches, 3 inches, etc. Use the test of nothing as a reference as a start. This will allow you to calibrate for false positives, and take note of the settings you are using. Will some settings work better than others? Be sure to define your frame of reference. Take a notebook and right down your results.

 

Then maybe you go find the snow, and see how the objects test similarly in the snow, on the surface of the ground. You may already know of a Benchmark you have already found and know it to be on the surface of the ground. Go see if you can find it in the snow. Perhaps in addition to the snow, in a flower bed or in the back yard you bury a series of objects of the various types I outlined, and bury one of each at specific depths so that when you have snow, you have your No-snow baseline tests on file in your notebook, and then when you have snow you test and note the snow depth, as it will be a factor. Say you have 6 inches of snow. How do the readings compare with 6 inches of air space. If there is then you may have a density factor based on the thickness, wetness and packed/unpacked density of the snow, and you may even test it based on the age of snow, had the snow hardened? Iced over on top? Been rained on?

 

I know this seems like a lot of doing to do, but in reality your results will really only answer most peoples metal detector questions in a general way. But you will know what your detector is capable of, very specifically in many many different situations. You may learn that there are variables that allow you to tweek your settings and still have a high level of confidence, and you will find that the advice from the others who posted to this thread will also apply. A fully charged battery is an important factor in consisting testing, and a cold battery will not give you the results a warm one will.

 

Good luck and good hunting, I will be in here where it is warm! :-)

 

Rob

[2oldfarts (the rockhounders)]

Will a metal detector work through Ice & Snow? Of course; they work by emitting a signal into the "ground" and then reading the changes in the reflected signal. Since manufactures of metal detectors also make models for "Underwater" use by scuba divers, it is a safe bet they have been tested for signal penetration in many different mediums. These would include water, silt, mud, sand, rocks, etc., etc.

 

The depth of penetration should be very close to what you get in normal use with your unit.

 

John

[+DBC FOR LIFE]

Your standard metal detectors are not actually "metal detectors" at all.... They merely detect changes in density of materials (metal is very dense). A true metal detector, or magnetic locator as they are often called is very expensive, which is what is surveyors use. I think the one we have was ~$1,500.00 or there abouts. Heres an example: Magnetic Locator. These search for iron or other ferrous metals in a vertical position. I have successfully found 2" I.P.'s down 4 feet, which is handy when you are looking for a section corner. Hope that helps,

 

Milan

[Bill93]

I don't think it is density--rock is quite dense also. Most common metal detectors are sensing conductive objects in their field. They emit an elecromagnetic signal that sets up currents in the object and then sense the change in the field.

 

The more conductive the metal, and the bigger it is, the further away they detect it. Thus Aluminum, copper, and gold are very detectable. Iron is close. Lead is not very detectable because its conductvity is way down from those other metals. This is unfortunate, given that it is common to use a lead plug to mark a point in a highway where there is risk of damage with an iron pin being caught by a snowplow.

[+DBC FOR LIFE]

The more conductive the metal, and the bigger it is, the further away they detect it. Thus Aluminum, copper, and gold are very detectable. Iron is close. Lead is not very detectable because its conductvity is way down from those other metals.

 

Actually conductivity has little to do with it. Of the metals you listed, here is the relative conductivity:

Aluminum: 30-45

Copper: 100

Gold: 65

Iron: about 12

 

My point being that real magnetic locators (as opposed to devices coined as "metal detectors") are designed for searching out Iron (usually survey monuments). Iron is almost as low as lead for conductivity but it will pick up iron easily and lead not at all (because it is does not have a magnetic field).

 

However, the magnetic susceptibilities play into it...

Iron: 720

Aluminum: 2.2

Lead: -1.8

Copper: -1.0

Gold: -2.8

 

The other devices transmit a very low frequency and look for this frequency to bounce back or an altered version of it which happens when it contacts a very dense object. (i.e. rock, metal, etc).

[Bill93]

>>Actually conductivity has little to do with it.

 

Conductivity has little to do with the magnetic (ferrous) locators most used by surveyors. Most people don't have magnetic locators.

 

Most people have the "treasure finders" that bounce back an altered signal. For those, conductivity is very important.