Bottle screw caps are my nemesis - Any advice to help ID them ...

[tonym]

Hi Gang:

I seem to be a magnet for screw bottle caps. They often repeat from 2 angles. They usually TID around 12/36-38 for me and sound good to my ear so many times I think I may have an Indian Head. I use GoneHuntings settings. Do you switch to coin mode to verify the screw cap? Do you have a method for id'ing a screw cap as opposed to a diggable target. Does anyone else have problems mistaking a screw cap for a coin? Thanks in advance for any advice you may offer.

 

[sube]

I dug a lot of 12.38s every one has been junk mostly screw caps or other junk I don't dig 38s of course a coin mask by some junk might lower to 38 but I'm not digging 38s no coins on the id chart come in at 38 very rarely as for 36 to 37 yes I dig these I run in ferrous coin combine. You might try deleting those #s out at that place for piece of mine.take several different coins to that spot and see what they read on the ground I bet none will read 38 try it .sube

 

["Dr.Tones"]

Hmmm? I honestly have over 1000 hours on my CTX now and can say I've literally only dug about 5 bottle caps? I wonder if they're made out of something different in your neck of the woods?

 

[chuckciao]

I hear you loud and clear and have the same dilemma not only with bottle tops but a lot of pop tabs and various other junk. I would be careful about dissing out 36-38 co because some Indians fall into that area. As far as ID'ing trash from coins, the key is listening for harmonic differences, and jumping numbers. Easier said than done. Let's hope that some experienced CTX users post some videos on this forum.
HH
Chuck

 

[Bill_S]

It funny you mentioned this. On one of my videos I just did I called the target before I dug it and it was a screw cap. They seem to hit in the 39 range on my 3030. You can see it on the video. It is around the 3:48 mark of the video. I can not post videos on here because they have ads in them so you will have to go to my youtube channel and search for a video called 4-21-13 Hunt with the Minelab CTX3030

 

[chuckciao]

Thanks Bill S,
Enjoyed your video. Hope you can post more on this forum
HH
Chuck

 

["Dr.Tones"]

Yeah be careful about discing that out. I've had indiana keep up in that range and I've also hade some deep warn dimes in that 39 area too.

 

[unearth]

For me, in So. Calif., the screw caps come in at 12-38 thru 12-41 usually. I haven't ever found an Indian penny in all my hunts here, so I don't dig those numbers. Wheat pennies come in at 12-40 usually, but again I find so few, maybe a dozen or so in a year, it really doesn't make sense to spend my time digging those numbers. If I lived in a place where older coins were found consistently, mid-west or east coast, I would be digging any repeatable signal with a good tone.
Good luck in your quest.

 

[JamesM]

I agree with Dr.Tones and chuckciao about not discing that out....I dug a 1902 IH last Saturday that came in at 12/38 at about 8". It was a good two way signal, but wasn't repeatable at 90 degrees. There was lots of iron trash around the target, and that probably explains why it didn't repeat at 90, and maybe why, it was 12/38, but it was good enough that I was confident it wasn't a false.

As for telling the difference in a good 12/38 and a trash 12/38, I'm sure that everyone that has a decent amount of time on the CTX can make an educated guess. As for me, I use depth,....If I get a 12/38 at 2-4", I figure it is a zinc or a screw top...at 6-8", I'm gonna dig it every time. The same thing applies for those 12/44 smashed aluminum cans and a 12/44 dime, but it is simple to tell the difference if you lift the coil a foot or two off the ground. As for switching to the default coin mode...If I recall correctly the default coin mode uses "high trash" separation, and the settings you are using use the "ferrous - coin" separation, so it is entirely possible that you would get different TID's with the different modes, but you are still left with the same dilemma...to dig or not. The more time you put in on the machine, the better you will become at making that "educated" guess.

 

[PowerDetecting]

I always notice a little grunt at the end of the swing. I dig them every once in a while just to see if thats what it is and it always is.

 

[tonym]

Thanks for all the advice guys - as soon as the ground is not concrete I'll try some of these tips out. No rain for about 10-12 days here.

 

[chuckciao]

JamesM,
Thanks for some really great tips that we all can apply.
HH
Chuck

 

[Larry (IL)]

I think you are "spot on" James I still dig some screw caps but I usually am pretty sure what I'm digging when I do. Just hoping I'm wrong thinking it might be a ring or some other goodie and it really doesn't take all that long to pop a shallow screw cap out of the ground.

 

[Des D]

Hi tonym,

There's some sound advice in the replies here.
For example, depth indication can be [ a rough guide]...ID numbers and possibly tones as well.

An interesting theroy is the [regional variance] in screwcaps however this might be more down to different manufacturing tolerances etc.
This I know to be true when several years ago I researched pull tabs and found that to be the case - all pull tabs were not created equal!
The same must also apply to screw caps?

This brings up another important point: for example, say several caps are dug in a row and they ID as 12 38, then the next signal shows 11 39 and when dug it's another cap of the exact same variety.
However, what might have occurred here is a case of [irregularity] The cap might be folded inwards, squished up, flattened or torn in some way?
This would account for the variation in target ID's because the detector interpreted the information and accounted for the irregularity or difference

So, this looks likely to continue as in your words, "my nemesis!"

Good Hunting

Des D

 

[JamesM]

Here is another one for you...On my CTX, a pull tab "usually" comes in at 12/15 or thereabouts. However if you separate the tab part from the pull "ring" part, the ring can hit at 12/10 - 13, and that is in the nickel range. I dig and find lots of nickels, because I listen for and investigate all low conductive tones and TID's, but like Larry said, I usually have a pretty good idea of what it is before I dig it. How do I know....I really can't tell you, but I do. I think it all boils down to familiarity with the machine, and being able to evaluate the site that you are working.
IMHO, if you are finding clad and trash at 2-4" and wheats at 5-6", that should give you more than just a rough guide as to what that next 12/38 at 2" is. There is a park that I often hunt, and I found old silver at 6", and 20' away found a 1965 clad quarter at the same depth. There is 12" of fill dirt in half of that park, and I dig more trash there than most of the other places I hunt, simply because I don't have a good "feel" for what that next target is, but most of the clad and trash is still in the 2-4" range. I would sure like to know where they got that fill, and what is under that 12" of fill .

 

[Des D]

Hey tonym,

Following on from what I posted yesterday, I made a lil' experiment for you to show what can happen with screw caps, in fact a lot of targets really if they become damaged or mishapen in some way.
I took a regular screw cap (one I found) and with CTX motionless on a test bench and the only adjustment was Target Separation High Trash
the cap was passed flat across the coil several times to get a consistent target ID FE 12 CO 39

The cap was then cut once and the test repeated and target ID FE 12 CO 32

It was then cut a second time and the test repeated which showed a target ID FE 12 CO 28

Then I stomped and squished it and the test repeated showed a target ID FE 12 CO 26

Many years ago the same was done with an Explorer XS and a cap flat onto the coil showed 28 and the more I 'damaged or changed the shape' the more the Target ID varied.

Shown below is the screwcap and target values.

I hope this helps.

Des D