Metal Detectors And Hunting

[+bullionhunter]

I was wondering how many people resort to using a metal detector when not being able to find a benchmark. I want to buy one and was wondering how helpful they can be. I would also use it to search for coins and stuff.

Any suggestions on a brand or model that is of good quality at a reasonable price?

[+Kewaneh & Shark]

There is much to be found by searching the past threads. Here are a few on that topic you might find helpful.

 

Useful metal detector, or just junk?

 

Bench Mark Hunting And Metal Detectors, Locating old relics

 

Need Advice For A Metal Detector For Bm

 

Metal Detector Recommendations

 

Using A Metal Detector, Sometimes the GPS just isn't enough

 

Metal Detectors In Winter, Usage questions

 

- Kewaneh

[2oldfarts (the rockhounders)]

If you decide to get a detector for benchmarking be sure to go to several disks that you have found and learn what they sound like. Different metals will make different sounds (with most detectors) and you can learn to rule out many hits from the sounds. Or buy a really good unit that lets you discriminate out certain metals.

 

John

[+Airmapper]

Now I have a reason to brush the dust off the old radio shack Metal detector I got years ago, shurely it'll pick up a Benchmark.

[lumpynose]

How far down do they detect? I went hunting for this BM this last Sunday and didn't realize until I got there and re-read the description that it's 14 inches below the surface of the ground.

 

http://www.geocaching.com/mark/details.aspx?PID=HT2454

[Gnikhog]

lumpynose,

 

I would generally say that the detection depth is directly proportional to price and the operater's skill. I have a low end BFO-type detector ($65) that has a maximum detection depth in the 8 inch range (based on empirical data). Factors like soil composition and moisture do affect my results. Search coil size, oscillator frequency, and discrimination also differentiate a wide range of detectors. I have heard that PI-type detectors are capable of detecting objects at much greater depths but I have no experience with them.

 

While a metal detector can be a time saver for marks near the surface, there is no subsitiute for careful measurements as per the datasheet for deeply buried marks like the one you mention (HT2454). In fact, recovery of this mark should only require careful measurements from the two RMs and a shovel!

 

/John

[+ddnutzy]

Yesterday I went hunting for 3 bm's with 3 rm's each. I used the metal detector to find 2 of the bm's and 6 of the rm's. MZ1603 and MZ1607. The other one I didn't need it. Without the detector it would have been difficult to find any of the bm's or rm's for those 2 stations.

[+Renegade Knight]

The specialized detectors that I have used can find an iron pin fairly deep. However being specialized they are tuned for iron pins which may or may not have a benchmark disk attached to them. Typically they didn't.

 

I'd flat out ask a local surveyor who uses a metal detector in their job what they use and why. Maybe it's always the specialized metal detector mayby they use another type for disks...

Edited September 21, 2005 by Renegade Knight

[+Kewaneh & Shark]

Most of the surveyors around here, myself included, use a magnetic locator called a Schonstedt. Because they work on the principle of magnetics, they only work on ferromagnetic metals, such as iron and steel. They will not pick up a brass or aluminum benchmark, but do pick up the steel rods and casings that many of them are constructed with. Their FAQ page says that their instruments will locate survey markers up to 9 feet below the surface (depending on the size and material of the object). I've been able to accurately locate property corners to nearly 6 feet down myself. These magnetic locators are not (generally) for the recreational hunter, though. Most are priced between $900-$1000 with a few specialized instruments in the $2500-$3500 range.

 

- Kewaneh

[mloser]

I have enough to schlepp around with a GPS, datasheets, etc, and whatever I add to the mix has to be easy to carry, and small enough that I will want to carry it. In short, it has to fit into my backpack or I will leave it in the car more often than not and regret that decision. (Right now I tend to leave the backpack in the car more often than not, thinking "I will be able to find the mark easily.. it is just on a bridge abutment, on a rock by the road, etc" only to find that it is covered in brush, dirt or something else and I need to return to the backpack to get my tools.

 

My solution, which is far from ideal, is a kids metal detector branded by National Geographic and available on Ebay for about $30 at any given time. It comes with a cheap plastic handle and extender, but I have lost those pieces. I simply carry the "head" in my backpack as it has a handle built in. There is no usable sensitivity setting, no meter, no headphone jack, and it makes only one noise (it squeals out loud) when it finds something metal. The head is about 3 inches around so the search area is small, and so far I have found that it only will pick up a benchmark disk about 2 inches underground.

 

Am I happy with it? Yeah, since the alternative is to have nothing at all or a bulky unit I would have to grown a third hand to carry (was well as feeling a bit foolish carrying it with me at some times). Would I recommend it? Not really, unless your criteria for carrying things limits you, like me, to a backpack and what you can hold in your hands. Has it been successful? For the most part, yes. Obviously I haven't done any large area sweeps with it, but when I have measured as well as I can measure and can't see a disk, it has helped me finish the job.

 

I am keeping my eye on Ebay for a better unit at a low price that I won't feel bad about altering. My plan is to remove any extraneous extensions that are meant to make the unit more comfortable to use such as handles, length of tubing between the head and the coil, etc. The key is "low price" as I couldn't bring myself to mutilate a $250 detector.

 

BTW, I HAVE tried the handheld units used at airports and concerts. I worked at a job with a security department and they had a number of them, so I grabbed a couple different ones and tried them. The detection was about as good as my "toy" one--2 to 3 inches, and they are fairly expensive, so I didn't feel they would be worth the money at all, despite their small size.

 

One thing I haven't tried is one of the "pinpointer" detectors. Does anyone have any experience with them? My guess is that while they can detect deep, their spread is (intentionally) near zero. They are meant to be used as a follow up to a regular metal detector to help you determine how deep the item is, not as a primary detector. Their size is tempting though!

[+bicknell]

I have to say I'm disappointed in my metal detector success in the end. We bought one a while back, and have tried it on about two dozen occasions. To date I have a single find, and that was a disk which was visable on the surface and simply covered with cut grass.

 

In the end I'm not sure if it's operator error, or that simply we're looking for benchmarks that are gone. I'm going to keep trying with it, but I'm a bit more down on them than my initial success indicated.

[Bill93]

I have a middle-model RatShack detector. It is sensitive to all metals, with a "discriminator" control whose effect is not clear-cut. The thing I like most about it is that instead of either beeping or not beeping, it can be adjusted so you hear subtle changes in the tone characteristics and strength, and you can learn to interpret these with practice. Its meter is useless.

 

Headphones are important when around traffic or it is windy.

 

Be aware that near any present or former railroad you will find enormous quantities of discarded hardware and if you are unlucky iron-bearing slag used as ballast.

[+ddnutzy]

I have to say I'm disappointed in my metal detector success in the end.  We bought one a while back, and have tried it on about two dozen occasions.  To date I have a single find, and that was a disk which was visable on the surface and simply covered with cut grass.

 

In the end I'm not sure if it's operator error, or that simply we're looking for benchmarks that are gone.  I'm going to keep trying with it, but I'm a bit more down on them than my initial success indicated.

Bicknell,

I don't know what kind of detector you have but I have a cheap radio shack detector that isn't much good over 6 inches and even that is suspect. I also have a whites classic 3 that is invaluable to me. I've probable found half of my finds with it up to 15-18 inches deep. It's heavy but worth it to me. Hell, my pack weighs about 15 pounds.

 

Dave

[Difficult Run]

I have a White's Spectrum which does a fantastic job on any type of buried metal. It can easily detect a benchmark at 2 feet. I've even found an 1853 quarter at 12".

 

A friend of mine has a White's Classic II, which for some reason has better sensitivity to brass and copper. For price and simplicity, this would be the detector I'd use for BM hunting.

 

Bicknell, I believe your detector is a Garrett GT250, if my memory serves me correctly. That's a nice detector. The important thing when detecting is knowing what the detector is telling you. With proper adjustment, ground balance and practice you should be able to find a benchmark even in a field of beer cans.

 

- Mitch -

[lumpynose]

lumpynose,

...

While a metal detector can be a time saver for marks near the surface, there is no subsitiute for careful measurements as per the datasheet for deeply buried marks like the one you mention (HT2454).  In fact, recovery of this mark should only require careful measurements from the two RMs and a shovel!

 

/John

Ok, thanks for the feedback John.

 

(I couldn't find the 2 reference marks for HT2454; both are by power poles but the utility company or city is plowing the land under the power lines, probably to reduce fire hazard due to the dry brown weeds. I suspect that the reference marks have been destroyed.)

[+bicknell]

Bicknell, I believe your detector is a Garrett GT250, if my memory serves me correctly. That's a nice detector. The important thing when detecting is knowing what the detector is telling you. With proper adjustment, ground balance and practice you should be able to find a benchmark even in a field of beer cans.

Yep, it's the Garrett. It picks up all sorts of stuff (I've found a kitchen knife, pop top lids, small metal fragements, rocks that appear to have metal in them, etc). Benchmarks (when I've gone over ones where I know where they are) tend to make loud, long, low tone.

 

Part of the problem may be oversensitivity. After all this thing is supposed to be able to pick up a penny a foot down. I think a benchmark is easy relative to that.