GB_Amateur

This is primarily a coin and jewelry hunting topic, I think. Getting more experience with different detectors, I'm wondering if I'm seeing a common (but hopefully not guaranteed) issue. What I'm referring to is called 'wrap-around' and I'm sure it has other names. Basically the low end of the induction balance (IB) ID scale is low conductivity iron and high end is pure silver. But sometimes with iron you get a high ID, usually in conjunction with the low ID. I've had this happen on three detectors but don't remember it on a 4th. The three are: White's DFX-300 w/ 950 concentric coil (least experience), Teknetics Gamma 6000 w/ egg-shaped conc. coil (intermediate experience), and Minelab X-Terra 705 w/ both 7.5 kHz 8.5" round conc. stock coil and Coiltek 3.0 kHz 6" round DD "Digger". I don't remember this problem with my Gold Bug Pro with any coil. I go into detail here with the 705 because I've used it the most in iron infested sites. The lowest ID on the 705 is -8 and the highest is 48. (All even numbers except 0 in between occur but never odd numbers -- by design.) Iron is anything below 0; high conductive coins (Cu and Ag alloys) are above 35 (usually) with silver dollar being highest US coin at 46. (Don't know what a pure silver round would read, maybe 48, but who drops those?? ) In the US Midwest we mostly have moderately low iron content (at least compared to US West) -- may be exceptions in iron mining areas like Minnesota and Michigan Upper Peninsula. I've seen phase auto at 35 with the 7.5kHz coil and 8 or 9 with 3 kHz "Digger" (don't know why the disparity...). I run max tones (~30 of them?) in "Coin and Jewelry" discriminate and alternate between "all metal" and notching Off below 0 and also notching Off 48. Note: this detector has a prospect mode but that operates quite differently and I haven't used it for hunting coins, although I see that some have. Even with the notching described above I get 46's and even 44's on iron targets. In all metal I can hear the jumping between iron ID's and high conductive ID's, but this can (and does!) happen when you're going over a coin near a nail, for example. The hope was that I could listen to tones and not have to look at the screen, but that doesn't seem to work well for me in the iron infested parks I hunt. I'm sure with more experience (and, yes, I've read Randy Horton's "Understanding the X-Terra" multiple times) I'll get better, but I still find myself, even in max tones, having to look down at the screen way more than I would like. So I guess I have a two part question: 1) is this an inherent problem in all coin hunting and multipurpose IB detectors, and if not, which ones are immune to it? 2) Do you have tricks, besides over-notching, to work around this problem? I've found enough old coins that I don't want to notch out halves (ID=44), because I know, although rare, they are out there. Lastly, I'm not interested in modern coins, although those come with the territory. So far I've found old coins at shallow depths (4 inches or less) and none deeper, although I'm sure they are there. I dig lots of pulltabs (square but mostly ring & beavertails) and don't mind that. There are coins in that zone and I'm willing to put up with the Al in order to find them.

Interesting. Where do you set the V-break? Leave at 0? Normally below VID=40 is considered ferrous/iron but of course some non-ferrous (like small gold) will come in below that. Are you saying your trick eliminates all iron or just the worst, lowest conductivity (e.g. below VID=20)? I have some iron infested sites I'd like to try this on (but not the next couple weekends as I'm out-of-town for both )

I also have a Garrett Carrot (ProPointer AT) and wonder how any coin hunter used to get along without a hand-held pinpointer. I'm pretty sure (from what I've read and also from experience) that the sensitive part of the shaft is about 1/2 inch (~1 cm) up from the tip. In fact it's said to be even more sensitive than the tip! When I get a signal I lay the GC on its side and hunt around the ground with the side of the shaft, assuming 1/2 inch up is the sweetspot, to find the maximum response (if the item is close enough to the surface to give a response). One nice feature of the GC that it took me a long time to realize is that you can desensitize by just keying the switch. I run mine on gain=3 (the highest) and desensitize as I get closer to the target when digging. I agree that when in a hole it's not always easy to know if its the tip or the side that is picking up the target, but by desensitizing I can almost always distinguish which. And sometimes with a really large target (not a coin) I have to change the gain to 1 and then desensitize. But that's pretty rare. Also agree that multiple targets in a hole can lead to confusion, which is one more reason why I (and everyone else that I've read or learned from) assumes that pulling one item out of a hole doesn't mean you're done. Here, though, I use the main detector for a second sweep because often the remaining target (picked up by the pinpointer) is a junk target, and I need the discrimination of the main detector to tell me that. On a lucky day it's the junk I pulled out first and now the desirable object gives a much cleaner signal and VID to finish up on. Found a 1920 Merc after digging a nearby nail out of the ground last week. I've never had another pinpointer so can't compare or contrast. I just know I'd be lost without mine.

Good catch. (And nice find, ...maine.) All but the first year (1859) had the shield and it (along with 1860-1863 and some of the 1864) were Nickel-Copper alloy. I've not found any of the Ni-Cu (the earlier Flying Eagles also were of this alloy) but have one in my test set for determining VID. I've now found three of the standard alloy (95% Cu, remainder tin and zinc) Indian cents and all came out of the ground with that green color. In fact, without seeing either obverse or reverse (which are usually caked in dirt) if I see the green rim I feel like I've got something good. It's interesting that the Wheat cents I've found (only two so far: 1945 and 1953-D) weren't green. They have close to the same alloy -- 95% copper -- but over the years the remaining alloys have been listed as tin and zinc. I don't know if the relative amounts of the two minor alloys have been held to tight tolerance or whether those two vary over the map. So possibly the green color depends upon this. Saying all that, maybe it's the amount of time in the ground, and even the chemical makeup of the dirt and amount of moisture that determine the color. The worst condition copper Memorial I've found came out of a bedrock crack in a creek, so that indicates that water is a contributor. It's currently at ~80% of its birth weight. It actually is colored a mottled (but not pretty) combination of green, reddish-brown, and black. (Note I haven't been talking about the 1982 and later "Stinkin' Zincolns" which deteriorate almost as badly and as quickly as a tossed aside banana peel.)

Add my name to the growing list of small coil lovers. (I don't have an XP/Deus, though.) If you live where there is modest to little trash (for whatever reason) then large coils are great. But when there are tons of nails, etc. I just drive myself crazy hearing all the trash. Most/all detectors are most sensitive to iron, I think because its magnetic (especially) and conductive properties combined. It's very abundant in the earth's crust (3rd most common by weight after Oxygen and Silicon?) meaning its inexpensive, also very strong, and as such has been used for centuries as a building material. There are lots of software (and hardware) tricks to 'ignore' iron, but they cost, sometimes severely, in sensitivity to the metals we want to hear/find. AFAIK, to date the best solution in iron infested locations is to use a small coil to minimize the amount of trash in its zone of influence. If that means extra sweeps of the 'broom', I can live with that. IMO it's worth it. And reducing the overall weight (preferably with an associated adjustment in balance) is a nice perk. In my area I use small coils 90% of the time, and that's not because I don't have intermediate to large ones. It's just what works.

Very impressive finds (139 Wheats, etc.)! All I saw in your post was 'TDI' -- which model? Also, if you don't mind, are you able to reject the old ring-tab (sometimes with beaver tail still attached) or do you end up digging them? Those can be deep since last made in 1975. I find way more of those than steel (beer) bottle caps, the new 'square' tabs, and aluminum screw caps combined. (That's with my VLF's, but I do have a TDI/SPP which I got for hunting native gold in areas with large hot rock populations but I'm not averse to using it in parks, especially after reading about your successes.)

Very nice find. I'm curious about the weight. According to The Redbook when minted this had a mass of 2.5 g. Can you put it on a scale and see how much is left? In my part of Indiana the copper coins get dissolved pretty badly from (I'm guessing) acid in the soil. I didn't expect silver to suffer the same fate. This holds true for Cu pennies caught in creek bedrock cracks. Of course coins wear when in general circulation so the difference from 2.5 g is only going to be an upper limit on how much material was lost in the river.

If you're serious, strongly consider buying these guys' (George Overton and Carl Moreland = Geotech) book titled Inside the Metal Detector ($29 online). I don't like to make superlative statements in general and especially about things I'm not expert in, but if there is a book on the subject that is even close to this one I'll be surprised. There are a handful of do-it-yourself detectors here and they tell you *why* they work on top of it. Even if you're not looking to DIY (I'm not) this book is easily worth more than the online price.

CORS: http://corscoils.com/index.php and NEL: http://nel-coils.com/index.php/en/ also make coils for the X-terra. From my web-searching it appears as though CORS has a much greater selection, including three at 3.0 kHz, six at 7.5 kHz, and four at 18.75 kHz. Having said all that, I don't have any CORS coils (yet) and the only NEL coil I have is the 15"x15" DD Attack, and that one is for my Fisher Gold Bug Pro. (Further, I've only tested it; haven't put it out in the real world yet.) Others here should be able to give good feedback on these brands. As far as not wanting to change coils to change frequencies, I don't see why this would be a big deal, other than the extra weight if you travel far from your vehicle. I change coils in the field quite often. And if you have a high-freq coil for native gold hunting and a mid- or low-freq for coins/jewelry/etc., how often in one day will you want to change frequencies?

Yes, but ironically the coils listed in the manual's specs aren't the coils shown on the manual's cover. I have the 150 mm round Super Pulse coil (as you know since you sold it to me as part of a used SPP package) and I've had it cracked open -- it is a mono coil. And I'm pretty sure the 12 inch open structure coil that also came standard with the Sierra model is mono (The "Aussie Mono") although it just says "Pulse Scan TDI" on the coil housing so maybe not.... Thanks to this thread (no sarcasm intended :) I bought one of the 950 style coils in this Garage Sale. I couldn't pass up the great price, even if it only turns out to be a collectors item for me.

I don't understand this. You imply that the average of the long and short axes represents the performance of a coil sufficiently well so as to be able to claim two different shaped coils are equivalent (or close to equivalent) in perforamance when these derived quantities match. I've never heard this. Or am I misinterpreting what you said?

The 95::5 ratio doesn't surprise me. If you look at a lot of fields of interest I suspect you will find some, even many, with similar numbers to this. Some people have bad memories of school and other learning experiences. Some of us can't get enough (and obviously you are in this second group). I'm surprised at the author's response. I hope (and am pretty confident) that person is the exception. In my experience when I get an answer such as this is that the person is hiding something, and usually it is a lack of knowledge, lack of confidence, and lack of courage to admit such. Since I buy a lot of books too, I'm curious as to who that author was. In reality, without hearing both sides of the story, it's a bit dangerous to draw too strong of a conclusion and I understand why you don't post the name here. (I wouldn't if I were in your shoes.) OTOH, I wouldn't mind if you sent me a message with the name.

Clear Creek which winds its way from the high Rockies (east side of Continental Divide) all the way down through Denver has not only produced profitable gold but also currently has parts where open (i.e. to the public) prospecting is permitted. Here are a couple listed on this (yes, Steve's) site: http://www.ci.wheatridge.co.us/1184/Gold-Panning http://jeffco.us/open-space/activities/gold-prospecting/ In June I visited the Wheatridge site. The creek flow at that time was still fairly strong so I was unable to get to the northside, but that is where the tailings are located. You may be able to ford the creek now, but if you park at the public parking area on the East side of Youngfield you can walk under the I-70 bridges along the north side of the creek and access the main area that way. (It's not an easy traverse if you're carrying a detector in your hands, though. I recommend a walking stick to assist you.) I'm vaguely familiar with the 10 miles further west (second link) but didn't visit there recently. My recollection is that large scale commercial dredging was done there in the past. That alone ought to indicate it's worth checking out if you have time. I was told (by reliable sources) that metal detecting in Wheatridge city parks (first link above) requires a permit. I don't know if this applies to the above gold-panning site. To be on the safe side, if you're doing more than collecting paydirt to pan, you might want to look into that, although it would probably take a letter-of-the-law person to object to someone using one in the placer tailings. These laws are typically written (agree or not) to prevent people from damaging public greenspace (e.g. manicured city parks). Good hunting!

OK, I guess I don't get it. If the government takes the strong arm approach and says "here's the law..., it's our right..., you are required to comply..." we get up in arms. If they ask our permission we ridicule them.

There is another option which isn't quite as sound but also is easier to reverse: tape. I use Scotch Super 33 vinyl electrical tape (3/4 in width -- far the most common) which is widely available at hardware and big box lumberyards. One key technique to remember when using vinyl tape: don't stretch it! If you do it will find a way to unstretch with time, often costing you your seal. Even when done carefully the tape will eventually wear down, but I've got tens of hours on my Gold Bug Pro 5 inch round and it's still tight. Silicone sealant is great and once you're sure you want to go that direction then I agree. Its biggest problem is that sometimes it's too great, as in being difficult to remove. You can usually break attached parts loose by cutting with a knife, but getting all the old silicone off is a real pain, as in nearly impossible with some surfaces without damaging them. I once asked a GE chemical engineer (GE has a industrial brand called 'RTV' but also supplies the same stuff for home do-it-yourselfers which you also can get at hardware and lumberyards) how to remove RTV. I was specifically looking for a solvent. He said there was none known, but one solution that some have used is to soak in toluene or xylene, which causes it to expand and weaken. I've tried that but you still have to scrape the surface in the end. (You likely know those two compounds need to be handled carefully as they are carcinogens, although probably not so much so with only occasional use in well-ventilated areas. Also a concern is whether they attack the plastic you're trying to clean....) Another issue with silicone is that it doesn't adhere to all plastics. In fact it's not great with some coil housings and covers. (It seems to work well with some plastic compounds used for that purpose, but not all.) So experiment if you can. An even better sealant (IMO) for some coil housings and covers is Rust-oleum's LeakSeal (similar to "as seen on TV" Flex Seal but about half the cost!) because it has a petroleum base, unlike silicone which is, in my experience, either acetic acid or methanol based. That helps by mildly attacking the plastic surface leading to a better seal. Bottom line is that I agree with using sealants if you're making a permanent bond. Otherwise don't trim your fingernails because you'll need them (plus time) to scrape off the cured sealant, preferably during some time-shared task such watching one of the many treasure shows on TV this fall and winter.

Hear yuh there, strick. I've heard and read lots of complaints of people finding ring&beaver-tail pop-tabs. I love 'em, especially when the ratio of those to 'square tabs' (modern pop-tabs) is high. It's strong evidence of one of two things: 1) minimal amount of detecting since mid-late 70's when they fell out of favor in the aluminum can business, or 2) detectorists failing to dig items in their discrimination region. Either way there should be a lot of juicy targets remaining in old sites. Best wishes in your hunts.

You may be onto something. Magnetism and electricity are close allies (look up Maxwell's Equations on Wikipedia) and even a static field is going to cause problems with a dynamically sensitive device -- like a metal detector. Modern coil housings have conductive inner coatings which have two purposes: minimize static buildup and shield the coil from from electromagnetic interference (EMI). If charge can build up between the outer surface of the coil housing and the inner surface of the protective cover one would expect problems. (Would be nice if Carl M. or Dave J. could elaborate, but they're busy building a new First Texas megadetector. )

I've been spoiled here by Steve's detailed and vast list of reviews of metal detectors used specifically for finding gold. Even though (from what I've read and seen) the use of a hand-held pinpointer is much less common among gold hunters than coin hunters, I'm wondering if anyone knows of a website the multiple reviews of those devices for any treasure hunting application. (Did see Steve's Garrett Carrot review in Gold Prospector mag several months ago.) There are quite a few to choose from, most in a common price ballpark (+/-) and it would be nice to see the features listed in a common format.

Would this happen to be the one about searching for the Lost Dutchman Mine? (Maybe I shouldn't ask, since you could have told us more about the show in your post -- I accept and respect that you have your reasons.) I've watched most if not all of these treasure shows. The biggest problem I have is trying to figure out what is real and what is planted/fabricated. The good news is that when you use non-professional subjects (i.e. untrained actors) it's less likely they'll be able to fake you out. The second biggest problem is putting up with all the drama/conflict b.s. Some shows are (far) worse at this than others. Third issue is all the voodoo/supernatural/pseudo-science crap. That is easier for me to ignore, and I guess it brings in audience (=advertiser $) so if that (and a bit of drama) is what it takes to get something decent on the air, I'll put up with it. Anyway, I was disappointed the Lost Dutchman show didn't have a second season. Still not sure about the veracity of all they showed (Jesuit connections, etc.) but the leader of the search team was likeable, seemed knowledgeable, and half his group appeared to know what they were doing. The other half....

It's about time someone spelled it out here. Television is a for-profit enterprise. Have you guys ever watched (or even flipped through) what is out there on cable? Ask yourself "why do they put this crap on?" The answer is pretty simple (and unfortunate/sad) "because that is what the TV audience wants to see." We have several channels whose names (and initial intent) is to educate: History Channel, Animal Planet, Discovery Channel, and National Geographic Channel. (All of them have treasure/gold shows, BTW.) Yet all of them have a plethora of garbage. History has the extraterrestrial alien believers every Friday night, Animal Planet puts on shows about sea monsters and Sasquatch which try to fool you into thinking are real (and 'fool' is a nice word -- they effectively lie to you in some cases). Discovery has "Naked and Afraid". I can't think off hand of what Nat Geo has that is misleading/phony, but I'm sure not interested in all their drug trafficking stuff. Are you? Having said that, what choice do we have? IMO, these are the best channels on mainstream pay cable when it comes to adventure, nature, science, and technology! Remember when 'TLC' meant "The Learning Channel"? A&E was really about (less than brain-dead) Arts and Entertainment? Have you checked them out lately? (Do so on an empty stomach because you'll have one afterwards either way.) Fact is that the four mentioned also have some decent shows -- you just have to filter through a lot of garbage. At the same time you need to watch ANYTHING on TV or the internet (including this site ) with a grain of salt. Anyone with an opinion (and that's everyone) and a keyboard can claim things as if they are based upon decades of scientific evidence, regardless if they were just made up. And TV isn't far behind that. If it sells then the veracity is secondary/unnecessary. But this doesn't stop me from watching, just watching selectively, and with a skeptical eye.

Next time I hear a sight is "hunted out" I'm going to remember this. Thanks for sharing your excitement and reminding us that it's still worth the effort.

This is way cool, for multiple reasons. 1) under the "everything isn't known" category, here are two long ago recognized and studied metals being alloyed to make something completely previously unknown. 2) when one is asked "why is gold so valuable?", even though its inert (non-reactive) qualities have long been recognized and appreciated, the reality is that its rarity (rarest element on earth with a non-radioactive isotope), artistic value, and effectively monetary 'aura' (look up the origin of that word!) are the real reasons. But tulip bulbs come to mind.... 3) although this article emphasizes the medical application, and for good reason, what is to keep this from being a contributor to other metallurgic applications? Titanium is a space age metal because of its low density and high strength/weight ratio. Making it even stronger... Let your imagination take it from there. Bottom line: any new industrial use for gold is going to increase its value. Fire up those detectors.

I can confirm that. "Can slaw" (pieces of aluminum cans that have been shredded by lawn mowers) give strong signals. Typically this is in the 60 --> 70 ID range on the GB Pro's discrimination scale. But aluminum foil can envelop a wider range, since the conductivity can be low (for small pieces) and high for large chunks, especially flat chunks. Gum wrappers, cigarette packs, and thicker foil used in grilling food can cover the spectrum from low 50's into even the 80's in my experience. And large pieces of aluminum cans are very conductive, also. Thanks for the tip. I'm going to put the 11 inch DD on this weekend and see if I can go deeper. I'm gaining confidence that the sites I'm searching are virgin (i.e. not recently searched by detectors) so deep is where the old coins are likely to be. That's the treasure I seek.

Well, I'm far from an expert, but I also use the Gold Bug Pro with the 5 inch coil. You probably are aware that US 5c pieces ("nickels") hit in the high 50's, typically 57 or 58. The old "ring + beaver tail" pulltabs also hit here, but since those went out in 1975 you shouldn't get too many, unless it's a park that hasn't been searched in which case it's worth digging them, IMO. Also, I mentioned in another thread that I found an Indian Head Penny last Saturday and it showed ~74 on the ID, right about where you often find the dreaded zinc pennies! One thing I've been speculating recently is that corrosion/deterioration affects the ID of US pennies of all types. Yes, a clean copper should hit at 82, but how about one that's been sitting in the ground a long time? I don't know. I have books and web articles that claim that Indian heads hit at four different ID's on some White's IB's and Minelab X-terras. But there were only two different composition Indian Heads: 1859-64 cupro-nickel and 1864-1909 95% copper, 5% (zinc + tin). So how do you get four ID's with that? My current theory: corrosion. As far as the spread on ID's, in my limited experience you can see this with coins that don't sit horizontally. Ideally a coin sits horizontally and you get a clean eddy current and tight ID, but get them off horizontal (especially vertical) and the variation is larger. How large? I'm not sure. Also I wonder about near neighbor trash. But one thing that helps is to rotate your body (and detector) 90% and scan the target again. Things that are asymmetric (e.g. nails and modern pulltabs = "square tabs") will give significantly different readings depending upon the orientation of the sweep with respect to the orientation of the object. As far as jewelry, I can't help you there but there are many here who can. I wish you well in your hunts!

Yes, but success is few and far between. The last time I found a silver coin was a dime I got in change at a Northeast Illinois toll booth about 10 years ago. (Value almost paid the toll. ) Theft and younger people cleaning out deceased parents/grandparents nick-nack drawers are likely the only way they get there today, and they wont stay back in circulation very long. I recall finding a Wheatie within the last month, but not particularly old and of no numismatic value. Jefferson 5c gives one a better chance because you have to read the date (until recently) to tell the oldest (first minted in 1938) from the new ones, unlike Wheaties where any nincompoop can cull out the older ones (pre-1959) by looking at the reverse. Saturday while MD'ing I dug up a 1904 Indian Head (bad shape due to our caustic soils) and it brought back memories. I started coin collecting in 1959 and never found an Indian Head, whether in change (my parents' back then) or going through bank rolls which I did quite a bit. So 50 years was enough time to clean out pretty much all of the Indian Heads. But you could find Buffalo nickels (last year 1938), Mercury dimes (1945), Standing Liberty quarters (1930) and Walking Liberty halves (1947) in the 60's, until the silver cleanout that left us with nothing but dull (in more ways than one) clad by about 1970. Thus 20-30 years and you still have (or had...) plenty of the previous designs in circulation but by 50 years they are gone. Wheaties more/less confirm this (58 years now). Believe it or not (I can't, or won't), we've had those p-o-s zinc pennies for 35 years now. "Those were the days, my friends. We wished they'd never end...."