What are "Crown Bottle Caps"

I have noticed "crown caps" and various "screw-on caps" are often lumped together under the term bottle caps but they are vastly different from each other.It is my understanding that crown caps are made of thin steel and pressed on bottles while screw cap are generally made of various aluminum alloys with the earliest varieties being made from lead.
Any thoughts on this subject and how various machines handle said targets or better yet how they don't ?

I have dug many steel crown caps that sounded and ID-ed way to good to pass up with F75s and V3s.On the other hand I can count on one hand the number of crown caps that even remotely resembled a good target in over 2 years and several hundred hours on the E-Trac .

Silverhound,
There are 2 numbers that a target has when describing it's makeup .....Conductive and Ferrous .........We'll take a pressed on pointed bottle cap ...( Your discription was correct by the way ) .....The bottle cap is made of iron which has a high conductive number on the E Trac we'lll call it 46 , yet has a number in the 30's in the Ferrous range .....We'll call the ferrous number 34........ So if you were running wide open on the E Trac , your E Trac would read 34/46 .......Again , 34 for the Ferrous, and 46 for the Conductive ....... Now you move to another machine .....A single frequency machine reads only the conductive number ......Lets say this machine has a scale of 0 to 100 .......Lets also say that you run over this bottle cap and it reads 46 .....If you run over a coin like a quarter , it will also read a 46 on the conductive .....So what do you do with the single freqency machine ? ......You can't discriminate the number 46 or you will be discriiminating all the quarters ...... So you basically have to rely on al lthe various tricks that are built into the various single frequency machines ....The AT Pro has an Iron Audio buttone that you hit each time you get into this range, and you check to see if it's a coin or if it's an iron crown cap .......If your area is littered with these crown caps like the parks that I hunt are , you have to stop and check each time you hit this number !!......It's a royal PITA !!!...... Move over to the E Trac now ......You have a matrix system ....When you hit the quarter , your conductive number is 46 , just like the crown cap BUT and a big BUT , it has a conductive number of 12 !!!......The E Trac reads both numbers remember ? .......So now you hit the crown cap and it also has a conductive number of 46, BUT the kicker here is that it has a Ferrous number of 34 !!!.....Same Conductive , but different Ferrous .....When you look at the little square in the matrix on the E Trac that shows the crown cap , it's COMPLETELY DIFFERENT than the one that shows the quarter ...... NOW you can cancel out ( discriminate ) the square the represents the Crown Cap , and you can STILL READ the quarter because the quarter is a different square altogether !!...... THIS Is one of the major reasons that makes the E Trac so much eaiser to use in a trashy park as you don't even have to listen to the crown caps because they are discriminated out ....They are already discriminated out of your pattern !!......Others that don't have this matrix system have to listen to them and deal with them !!....The E Trac users DON'T !!..... Single frequency users will have to stop and investigate the target , while the E Trac user just keeps on walking because it's a non issue .....If you read my thread on " I'm spoiled " it goes into this in detail .... Hope this helps you out .....Jim

That's a good way to hunt with the E-trac. But be careful when you get those deep coin signals because it will cause the ferrous number to rise into the upper numbers in my area at least. That's why I get a kick out of guys who remove the small upper corner line in the stock coins pattern because you can't air test a silver dollar with it in. They also think you can't find multiple big silver in the same hole with this line. I have not found a silver dollar with the E-trac or any other detector I have had in my 15 years of detecting. But I did find a silver coin spill withe the E-trac in the stock coins mode. It was 2 walker halfs,3 silver quarters,and 3 silver dimes in the same hole and it had no trouble hitting because the fact it had been in the ground so long the halo raised the ferrous number out of the range of that small line of discrimination. I imagine it would do the same to a silver dollar that has been in the ground awhile at any kind of depth. I tryed running it with out the small line and it didn't run as smooth in my area so I went back to the stock pattern.

Harold,
If it's the line I think that you are talking about , it's part of the # "1" Ferrous line , on the right hand side ........BIG Silver will hit there all the time ...Right around 1/ 40 or 1/41.. especially Slver Dollars !!..... Jim



Edited 1 time(s). Last edit at 03/27/2011 10:58PM by synthnut.

It will not hit there after it has been in the ground long enough to develop a hallo that will push the numbers past the 1st line. I wouldn't have found that coin spill otherwise!

I disc that first line out; just too much wrap around iron for me.

[www.bullworks.net]

silverhound Wrote:
-------------------------------------------------------
> I have dug many steel crown caps that sounded
> and ID-ed way to good to pass up with F75s and
> V3s.




Silverhound,
It's very easy to ID crown caps and screw caps on the V3 when using 3 frequency. When pin-pointing, the frequency that hits the hardest will tell you which cap it is. If 22.5 kHz hits hardest it is a crown cap, of 7.5 kHz hits hardest it is a screw cap, and if the 2.5 kHz hits hardest it is a quarter. Often times it will VDI at 83 and sound good but this will tell the tale every time. Many a times I have dug coins partially masked by a cap because I would bump the coil 1/4" at a time while in pin-point mode and watch to frequency change from 22.5 kHz to 2.5 kHz... it was a coin adjacent to a cap.