The word on coils

Dig24crt wrote:Marco
The missus is sitting here laughing.Has been using the same coil for ten years.
Dig

My info is straight from the manufacturers. Go back over the years and you'll see I've said the same thing before: 4 years premium lifespan on coils if used regularly. I don't doubt that this varies and it doesn't apply to coils that are used occasionally. Which means your wife's coil will still work, just nowhere near as good as it did 10 years ago. They don't simply just stop working. But after 4 years of constant use, they tend to become far less sensitive. There's a technical reason why this happens but I think I've posted it before and could''t be bothered doing so again. Don't worry, we laughed right back at your reply. Wonder how much gold you've missed?

Dig24crt wrote:Hi Jim and Cheryl
Hope you have a great 2012
Yeah still the same story Jim 20 metres or 20 mins whichever comes first.
Cheers Noel

No change there Noel. Have you got Leonora on the books this year
Regards Geof & Carol

nero_design wrote:...... Don't worry, we laughed right back at your reply. Wonder how much gold you've missed?

Wonder how much you've found?

I opened up a coil that was falsing so badly it was next to useless.
It was less than two years old but it was out of warrantee.
The coil falsed from the moment I bought it, but that is another (sad), story.

As I had nothing to lose and I am the curious type, I decided to open the coil up and have a go at fixing it.
I was astounded to see how some of the critical materials had dried out to the point of disintegration.
There was a quarter inch wide strip of masking tape holding the coil wires that are wound around the outside of a foam sheet.
That foam insert was covered on the top with a paper-like sheet sprayed with an "anti-interference" black spray coating.

The masking tape was disintegrating from drying out and the foam was just starting to fall apart.
The anti-interference paper was brittle from drying out and had to be handled very carefully so as not to
have to replace it completely (buying the spray and finding a suitable replacement paper or whatever it was.)

All this to Nero's point of coils not working well after four years or so of continuous use.
I do not think all coils will be in this condition after a couple of years
and I do not think all coils are manufactured this strangely and cheaply.
I do think coils have a limited time where they are optimal in their response although that time may differ from coil to coil.
And no I will not name the coil manufacturer.

btw, I was able to fix the coil and it does not false at all not matter how hard I try.

Happy New Year to everyone.

Gday

I dont doubt that coils do have a service life but I would be reluctant to state what that would be, whether they could become less sensitive over time ? I would not be convinced of that, but from what I have seen occur with coils the only issues seem to be that they either dont work at all or become "touch sensitive" meaning they will produce annoying false signals when rubbed or struck on objects, or even at the end of the swing, usually due to the coil windings or other wiring becoming loose inside the casing or having damage to the wire where it enters the coil case.

I have my original minelab 8" mono coil that I got either with my first sd2000 or s2100, it was a used coil then, and I still use it on the gpx4500, I operated on it a couple of years ago after getting some falsing from it, and found the wiring loose inside, stuck it all back together and its still going strong, I have been reluctant to buy a commander 8" round mono because I dont know if it would work as well as this one does? as I wouldnt even try to guess how much gold this coil has found.

There are many older style coils that are still around that are in perfect condition, but its a case of suck and see, taking the chance on buying them and trying them out on the ground, particularly in the case of the larger sized coils that a lot of people buy but rarely use, as long as they have been stored properly and not abused then they should be fine and not only that if you dont use a big coil very often then why invest so much money in the latest large sized coil, the money is better spent on the sizes of coils you use the most.

There are of course some coils that perform better on one machine model over another, and some that were purpose made to suit a particular model so you have to consider that when shopping about as well, many coils that were still very good coils have been shelved due to the invent of all the super light weight open spoked coils, I am a big fan of the lightweight coils for their ease of use but still believe that in some instances some of the older less sensitive (not sensitive from age but from original design) coils are better to use as they seem to ignore more of the ground mineralisation making it easier to hear the faint deep targets.

cheers

stayyerAU

Its an interesting post Stayyer
Hopefully Marco will give us the details of the people he spoke to in each company and the percentage losses of sensitivity.Because this forum was designed for the betterment of fellow prospectors,this information is invaluable.
Cheers Dig

It would be interesting to know if any of the coil manufacturers or metal detecting companies do spot checks on their coils (quality control).............ie Subject the coils to the rigours of use that prospectors subject them to (laboratory simulation)....not just doing a continuity test with a multi-meter.
One guy told me he rang up to complain about a faulty coil and was told to send it back and it would be replaced......they said they don't repair them.
What concerns me is that coils are expensive for what they consist of and how they are assembled (from comments of Forum members)......I have always advocated that I don't care how much I have to pay, so long as I get what I pay for !!!........I'm happy to pay an extra amount of $$$$$$ for a "well constructed" coil........(does anyone know where coils are manufactured that we buy in Australia)?

nero_design wrote:

Dig24crt wrote:Marco
The missus is sitting here laughing.Has been using the same coil for ten years.
Dig

My info is straight from the manufacturers. Go back over the years and you'll see I've said the same thing before: 4 years premium lifespan on coils if used regularly. I don't doubt that this varies and it doesn't apply to coils that are used occasionally. Which means your wife's coil will still work, just nowhere near as good as it did 10 years ago. They don't simply just stop working. But after 4 years of constant use, they tend to become far less sensitive. There's a technical reason why this happens but I think I've posted it before and could''t be bothered doing so again. Don't worry, we laughed right back at your reply. Wonder how much gold you've missed?

what a crock i'v never heard this befor i'v talked to a bloke that test the N/F coils and that he's still got the old white N/F coil and works like it's still new. the sd2000 with the orig 11dd coil, a mate still picking up gold at good depths and at all size. if you look after your gear it'll last a longtime. what manufacturers said this to you?
cheers
stoppsy
ps making a comment like that you would wont to be able to back that up and not by typing it.

A friend of mine had been using an 11" supergoldsearch mono for a couple of months that we were detecting last year.He was finding the odd larger nugget but not getting the smaller gold which I was getting regularly.The plug connection went bad so we purchased a new plug to put on.I tested the coil after fixing it but couldn't beleive how noisy it was compared to the new commander.He said he was used to it and it had been getting worse.
He bought himself a brand new commander after this and immediately started finding small gold each day.
Recently myself and 2 other friends have purchased 3 NFA,s.All 3 exibit touch sensitivety to sticks and leaves only.These have the litz sticker on them.
All earlier NFA,s worked perfectly(grey ones)that I have used including 18",16",17x11" and my 2 year old 14x9.They never had this issue.
As this is a minor issue and they work very well at finding gold I have worked around it.But it does raise the question as to whether there is a continued quality control or testing being done during production as these type of issues are very easy to pick up on.
Steve

stoppsy wrote:

nero_design wrote:

Dig24crt wrote:Marco
The missus is sitting here laughing.Has been using the same coil for ten years.
Dig

My info is straight from the manufacturers. Go back over the years and you'll see I've said the same thing before: 4 years premium lifespan on coils if used regularly. I don't doubt that this varies and it doesn't apply to coils that are used occasionally. Which means your wife's coil will still work, just nowhere near as good as it did 10 years ago. They don't simply just stop working. But after 4 years of constant use, they tend to become far less sensitive. There's a technical reason why this happens but I think I've posted it before and could''t be bothered doing so again. Don't worry, we laughed right back at your reply. Wonder how much gold you've missed?

what a crock i'v never heard this befor i'v talked to a bloke that test the N/F coils and that he's still got the old white N/F coil and works like it's still new. the sd2000 with the orig 11dd coil, a mate still picking up gold at good depths and at all size. if you look after your gear it'll last a longtime. what manufacturers said this to you?
cheers
stoppsy
ps making a comment like that you would wont to be able to back that up and not by typing it.

Hi Marco, unfortunately after about 3 months with no activity some of the threads dissapear into the ether. Could you be a sweety and repost the technical reason? I and I'm sure many members would love to see it.

cheers,

Steve

i realy can't see the manufacturers saying this as it would give them a bad name if the word got out and people would just stop buying the coils. why would they say this to you nero as your nothing to do with the company you only sell there gear nothing to do with there work shop, or are you working for them now?
cheers
stoppsy

i think JP could shed some light on this topic as he's always out detecting and knows what's what and would know about how long they last for. i don't think nero is going to respond to who the maker was who said this to him. i would realy like to know as then i'll mostly stop buying that coil.
cheers
stoppsy

nero_design wrote:My info is straight from the manufacturers. Go back over the years and you'll see I've said the same thing before: 4 years premium lifespan on coils if used regularly. I don't doubt that this varies and it doesn't apply to coils that are used occasionally. Which means your wife's coil will still work, just nowhere near as good as it did 10 years ago. They don't simply just stop working. But after 4 years of constant use, they tend to become far less sensitive. There's a technical reason why this happens but I think I've posted it before and could''t be bothered doing so again. Don't worry, we laughed right back at your reply. Wonder how much gold you've missed?

I contacted two of the "Manufacturers" Minelab and Nugget Finder to check if the above information had any substance. Manufacturers do not put a precise time frame or a use by date on a coils performance.

Thanks

Kim

well there you go so someones wife will be stll laughing then after all. nero if you can back up what you have said i would love to read it.
cheers
stoppsy

kim wrote:

nero_design wrote:My info is straight from the manufacturers. Go back over the years and you'll see I've said the same thing before: 4 years premium lifespan on coils if used regularly. I don't doubt that this varies and it doesn't apply to coils that are used occasionally. Which means your wife's coil will still work, just nowhere near as good as it did 10 years ago. They don't simply just stop working. But after 4 years of constant use, they tend to become far less sensitive. There's a technical reason why this happens but I think I've posted it before and could''t be bothered doing so again. Don't worry, we laughed right back at your reply. Wonder how much gold you've missed?

I contacted two of the "Manufacturers" Minelab and Nugget Finder to check if the above information had any substance. Manufacturers do not put a precise time frame or a use by date on a coils performance.

Thanks

Kim

i don't think they did say anything like this to you nero as you would have commented by now.
cheers
stoppsy

I thought I should add that I will also check with Coiltek when they are back from Holidays.
Thanks
Kim

I am quite involved in Electronics.....

Coils don't "wear out" they simply fail in mechanical terms.
the windings in a coil are when new, very rigid in their construction, which is a must for the box to be able to decipher when a pulse is reflected back from a target.
If the windings are loose , or are damaged electrically etc, the signal or the lack of it will not be interpreted buy the electronics in the box correctly and will either give false readings when nothing is there, or give no signal at all.
Glues and other fastenings will also break down over time and cause the above problems.
Some will have dust leaks that will let irons into the enclosure and null down the performance as well etc etc.... some plastics will get irons "imbedded" in their surface and again dull down the performance.
Coils could be made to last forever, but the weight of the unit would be to heavy to make it a viable proposition to swing all day........ so a compromise is needed....strength against weight.
Manufacturers will not give a lifespan due to the fact that their use will be varied.... some will get knocked around and scrapped badly, while others will have an easy life, so its impossible to tell...... its like how long will a car last.
I would say ALL coils could be fixed when damaged, but sometimes the cost and mucking around is just not worth the trouble.

stoppsy wrote:i don't think they didn't say anything like this to you nero as you would have commented by now.
cheers
stoppsy

Sorry Stoppsy, I was taking the last 3 hours to compose my reply. I'm afraid I've had visitors for the last two days and couldn't reply to threads online until I had sufficient time. You forget that unless I have something else to say, I simply don't have to reply and in most cases I couldn't be bothered... especially when people are going out of their way to provoke a response rather than ask something genuinely constructive:

If I want to quote someone I tend to ask them for permission and then quote them by name. I own and use all the major coils so obviously I don't have a problem with them. They are all very well made these days although earlier coils that are no longer made were the subject of considerable debate. And that's what we're talking about here... an older coil that is no longer made. And my reply was that I personally wouldn't buy an older, discontinued, coil [for use on a GPX]. I've also avoided mentioning brand names because this thread is simply about an older coil which wasn't even named by the original poster.

To the others reading this thread: ever take a look at an older coil? Ever wonder why some of those early black coils are no longer made in that color? Why did those white coils change in the sun to a yellowish tone? ... and why did the old plastic mounting brackets on some coils splinter and shatter? Some of those coils that did splinter were so highly regarded that many serious prospectors in WA and the NT would happily shell out for more than one and would replace them as soon as they shattered or broke. They were hard on their coils too. But this was years ago... Those folks that ended up taping their shattered coils to a stick did do with good reason: The coil worked a treat but they'd managed to shatter it against rocks or simply because they were very hard on their equipment. But we're not talking about the quality control or type of materials used here, are we? Because coils have generally been made to good standards over the years and all manufacturers have gone through changes since those series of coils were first made. Prospectors have been discussing this for years but i believe I was the only one with the initiative to speak to manufacturers and ask them directly. If anyone did so before me they remained silent on the matter. Since the effect will vary from coil to coil based on so many other factors (battery type/voltage/coil size/coil shape/length of use etc) ... it's not going to be something that they would likely discuss or publish because the results would vary from person to person. Just as they won't give precise depths for any coil or any machine. Since they don't offer depth assurances of coils or detectors, shall I therefore conclude that by your reasoning that there is no estimate on depth or capability? Those figures come from personal use and by testimonials of people using them. I guess you need to keep phoning people up. My conversation with them is still fresh in my mind and i have more than one theory why this is the case. It was discussed on this forum in much greater detail about two years ago. My theory as to why a coil could break down over time is that the energy emitted by the coil could eventually etch away the insulation around the inner wiring, resulting in a loss of field. On certain coils, you can actually hear a very high pitched whine emitting from the coil if you power it up and hold it near your head. Anything capable of producing an audible sound like that directly from a coil is also going to be emitting enough energy to affect the wire's coating over time, which would possibly/probably lead to the decay of the very effect of the coil. Just a theory, mind you. You would know that Litz wire (for example) has multiple strands, each with minute individual insulation which results in an expanding effect of the field. And I didn't claim the coils stopped working, just that I have heard they became less effective and less sensitive over time (years). I also note that this was not the case for all coils just those subjected to certain prerequisites.

Of course, if you are talking about early coils, it was VERY common knowledge that some would shatter after a certain amount of time in the field. Why is that? Well, I was told that this was partly because of a lack of UV resistant chemicals used in the manufacturing process and also because of the material used to form the coils. Even more recent coils have undergone changes to their resin brackets to replace them with what appears to be polycarbonate fittings at the weakest point where the mounting bracket is.

Anyone can use an old coil for decades and be pleasantly happy with the results ....assuming they weren't using that coil on a daily basis for years on end.

And Stoppsy, if you don't like the idea that some older coils once splintered or even became less sensitive over time, you should realize that these were some of the most popular coils ever made. They were VERY successful and were preferred over others by those who used them. Their equivalents today are manufactured differently to make them tougher and more resistant to the elements. As for the effects of high frequency energy pulsed through coil strands... it's entirely logical to conclude that this should likely result in changes to the effects of the coil's potency over time with constant use.

Of course, if none of the manufacturers you spoke to wish comment on the matter, you can believe whatever you want to believe. I think you can read between the lines if that was the official response. I also believe this is a forum thread discussing other people's thoughts. Those are mine. If your thoughts differ, so be it. In my opinion, a coil should last a great many years or decades if used intermittently. There are coils out there that must be pushing 50 years by companies like Metrotch and they still work today... but they've most likely spent the last 5 decades in storage. However, that's not what this thread is about, is it? And the response to my short reply is now turning into a finger-pointing exercise by people who are not only apparently unfamiliar with this previously discussed matter, but who ought to know better by now.

Marco
Nice deflection
Once again you are telling this forum that you have contacted all manufactures Trevor (or John) Ian and Rohan and you are telling Me and this forum
that because of information received directly from them ,Coils made by them used regularly lose their sensitivity after 4 years.
Dig

Dig24crt wrote:
....Coils made by them used regularly lose their sensitivity after 4 years.

That is a FALSE statement and you should know better.

The comments made to me was that "older coils that have been used every day, year in and year out were [sometimes] prone to losing some sensitivity over time after years of use". When I asked if there was a specific lifetime/lifespan of use before this was likely to be observed, I was told "about 4 years or so" but he reiterated that this was only for coils used every day for years at a time. It also referred to OLDER coils. Coils that are no longer made. Thus this would only apply to a handful of coils still being circulated because we know that there's few prospectors using their coils every day for years on end (assuming we were to take the comment literally). The impression I was given is that this can apply to all detector coils, not just those we were discussing. So if you feel that your coils are only used every weekend, every year ... I'd say your coil could run indefinitely with no way to guage the lifespan accurately. But I would also say that if you were in WA using your coil every day for years on end, your coil will lose some sensitivity over time. And I would NOT want to buy that coil second-hand if there was a chance that is was less sensitive. This is why I often recommend people check their second hand detector coils carefully when they buy from a friend or a stranger.

This is ALSO why you will never get specific depth comparisons .... other than a visual reference on an old SD 2100 brochure and a depth chart that shows up in Doug Stone's large hardcover Prospecting Australia books. There are too many factors in place. I would suggest that metal detectors are one of the very few electronic products that no manufacture will provide specific measured depth capabilities for. There are good reasons for this but that's another matter altogether. If I buy a car, I can find out how many miles to the gallon I will get from it... or I will know how many km before a full service is required. But cars and their lifespans are varied depending on use.

The same would have to apply to other electronic devices. I had an old AM-FM radio that I just replaced last week with a Digital Radio. Why? Because the signal was cutting in and out. The benefit of my new radio? Crystal Clear clarity. Sounds just like my old one when it was new. Did the components wear out over the years? You betcha.

[quote="nero_design"]

Dig24crt wrote:Marco
The missus is sitting here laughing.Has been using the same coil for ten years.
Dig

My info is straight from the manufacturers. Go back over the years and you'll see I've said the same thing before: 4 years premium lifespan on coils if used regularly. I don't doubt that this varies and it doesn't apply to coils that are used occasionally. Which means your wife's coil will still work, just nowhere near as good as it did 10 years ago. They don't simply just stop working. But after 4 years of constant use, they tend to become far less sensitive. There's a technical reason why this happens but I think I've posted it before and could''t be bothered doing so again. Don't worry, we laughed right back at your reply. Wonder how much gold you've missed?[/quote

You said it My info is STRAIGHT FROM THE MANUFACTURES.YOU MENTIONED 4 YEARS
ONCE AGAIN STOP DEFLECTING AND ANSWER MY POST RE CONTACTING MANUFACTURES

I've a hand built Aquacell Monoloop coil here that is 25" round, built for me in 1996 to be used with the SD2100 (pre Coiltek as we know it today) that still works very well. I also have a 24" Coiltek DD coil made way back in 2001 that still works very well even after finding hundreds of ounces of gold and being used for years in hostile places like the Pilbara and other such nasty places in WA as well as here in QLD.

Probably the biggest consideration with older coils with newer technology is if the coils inner shielding has deteriorated over time (heavy use) or as is the case with a lot of older coils, they do not match the specs well enough to work efficiently with the new Smooth type timings now available on the GPX series.

JP

" in hostile places like the Pilbara and other such nasty places in WA". Shame on you JP. The Pilbara nasty?.
Cheers Dave

Jonathan can you clear up a couple of Questions here that really have not been answered. (1) Do coil manufactors have any quality control on coils these days or do they just wait to see if they start getting back coils with a problem and then try and fix it. (2) and do the Manufactors do field reseach on new coils and older coils to see if they break down under field and weather conditions, example:- rough treatment against rocks, braches, dust penertration, hot temperatures of WA, NT, & Qld, Cold Temp. Vic, SA, NSW. Do ML have that system in place, or any other coil manafacture that you know of ??

Wombat

david wrote:" in hostile places like the Pilbara and other such nasty places in WA". Shame on you JP. The Pilbara nasty?.
Cheers Dave

The last thing I want for people to think is that the Pilbara is 'easy'!!! I have fallen down cliffs, nearly been burnt to death, blown away by powerful winds and driven absolutely nuts by flies and Black bees, not to mention being bogged, roads closed, near frozen solid, nearly trod on and been bitten by snakes as well as sharks, pricked and tripped by spinifex, driven hundreds of kilometers cross country to only end up 10 k away from where I originally started then to find someone had already beaten me to it, the list goes on and on........ yet I would go back there in a heart beat, the scenic views, the potential, the risk, the rewards and of course the people all makes the trials and tribulations of the Pilbara well and truly worth while. Like I said 'Nasty Places'

JP

sounds like fun mate, just like on the gp3000 dvd when you fell into the hole and smacked your knee on a big rock that would bloody hurt.
cheers
stoppsy

A mate still has and uses the original black 11 inch DD Minelab coil he got with his GP3000. He has worn through a heap of skid plates,and even through the bottom of the coil because he got too lazy to replace the skid plate. Most likely its full of dirt He repaired it with silicon and still gives the rest of us a hiding on numbers of nuggets.
Either its a great coil or he is on fire

kim wrote:

nero_design wrote:My info is straight from the manufacturers. Go back over the years and you'll see I've said the same thing before: 4 years premium lifespan on coils if used regularly. I don't doubt that this varies and it doesn't apply to coils that are used occasionally. Which means your wife's coil will still work, just nowhere near as good as it did 10 years ago. They don't simply just stop working. But after 4 years of constant use, they tend to become far less sensitive. There's a technical reason why this happens but I think I've posted it before and could''t be bothered doing so again. Don't worry, we laughed right back at your reply. Wonder how much gold you've missed?

I contacted two of the "Manufacturers" Minelab and Nugget Finder to check if the above information had any substance. Manufacturers do not put a precise time frame or a use by date on a coils performance.

Thanks

Kim

Contacted Coiltek this morning. The same response, Manufacturers do not put a precise time frame or a use by date on a coils performance.

Kim

You forgot to mention the bl--dy ticks.
DaveM.

david wrote:You forgot to mention the bl--dy ticks.
DaveM.

Now your talking about the real 'Outback' the Kimberley, that is something I like to keep very close to my chest..... mums the word on the Kimberley OK?

As for coils, depends on how you treat them, I tend to swap out my large monos every other season, mainly for peace of mind but also because I give them a flogging, in the scheme of things they are reasonably cheap relative to the return, but this is my perspective based on a professional approach. I still have a few old faithfuls laying about, 24" Coiltek DD, 18" Minelab Black DD, 25" Aquacells, 20" Nugget Finder XP DD coil, 16" XP Nugget Finder, 10" Joey (had that one for years), my original Coiltek Pinpoint probe coil given to me by John Kah (would not swap that coil for all the tea in china), couple of original Super Super light fiberglass 20" Nugget Finders, couple of Minelab 18" green mono's, all these coils have had their fair share of action over the years, some of them have scored many hundreds of ounces and all of them still work well (new technology taken into account of course).

I also own a Nissan Patrol common rail ute, the mines bugger these vehicles in less than 40 000 K whereas they don't seem to break the Landcruisers so much, yet I have over 70K on my Nissan most of which is off road and its still going strong. It all depends on how you treat them, rough em through the bush and they will break, treat them nice and they will give you reliable service for many many years.

Things to look out for when a coil gets a few swing miles on the clock; 1. Touch sensitivity 2. Scuffing through the coil housing 3. Damaged leads especially at the coil ingress point but also the coil lead end and other points of contact/wear throughout the lead 4. Loose foam inserts which causes chaffing and the failure of the faraday shield (more common with the old Green Minelab fiberglass coils) 5. Broken or stretched coil web/shaft mount points (pretty common in all the older coils from every manufacturer) 6. Cracks which allow moisture laden air to enter then condense on the the windings over night causing the coil to become very noisy and erratic as the moisture burns off the next day (this is a common problem in the tropics such as Nth QLD)

JP