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Bottle Cap And Pull Tab Primer


Mr Swing king

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Hey everyone. I've been detecting for a while now, but have for the most part stayed close to home. I noticed some posters call all beer caps crown caps, and some refer to square pull tabs. 

All that trash looks the same in my neck of the woods. Is there a primer on the difference between them?

 

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On the Nox 800 you can basically eliminate most of the pull tabs and bottle caps by setting a high iron bias and discriminating out VDI 11-20 but you will miss good finds including Indian Heads, Nickels and several other desirable relics. It’s a powerful tool but use iron bias and discrimination with caution 

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Discriminating aluminum can result in losing out on gold as they cross over. Crown caps, bottle caps which are steel should give off an iron signal at the tip or tail on most dd coils unless you discriminate iron out too much. The old ring pull style tabs are becoming fewer and far between so worth digging if they sound good, again many gold rings will be in that range too. Square tabs can be all over the place as there are so many styles. They often give off jumpy numbers.

Personally I rarely discriminate out unless in certain circumstances ie cherry picking ranges or when using my analog machine. If I do use discrimination it would be on the very low end of iron to cut back uncessary chatter.

If your fairly new to the machine try using the stock settings and get to know the machine before making too many changes. Takes a while to learn the nuances, of a machine and digging trash is a good lesson. When I use a new machine I will listen careful to the target and dig it to know what that target is. Once I have that foundation and build confidence on the targets responses then I will fiddle with the settings.

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They call them crown caps because they look like a crown when you turn them upside down.

Good luck trying to ID pull tabs and pull rings.  If you don't dig them, you might be passing up a nice gold ring.

If I don't feel like listening to trash signals, I discriminate everything below 20 and cherry pick mostly coins. When I run out of targets, I open up the teens.  Digging the teens is sometimes more work and requires patience.

You can tell I don't detect sites with a lot of modern trash very often.  I'm used to digging every non-ferrous target.  I rarely see a bottle cap or pull tab at the places I detect.

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Yeah, the only thing Im discriminating now is 1 and bellow. I know there's micro gold there, but otherwise I spend all my time digging balls of hershey kiss foil.

I'll have to double check my settings. Some pull tabs sound weak in one direction, but my gold tester ring still sounds really good. 

Also, in all metal mode the pull tabs go back to sounding like the gold ring.

 

As for bottle caps, I've been finding some that ring up 10-11, but like someone here mentioned, switching to 5khz makes them hit at 32 or so

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6 hours ago, kac said:

The old ring pull style tabs are becoming fewer and far between....

You haven't been in my neighborhoods lately.  Last year I discriminated against them and still in 311 hours of detecting I dug over 1200 (mostly tail-only, followed by ring-only and lastly the full ring-and-beavertail).  90+% of those masqueraded as USA nickels.

Some detectorists use the term 'square tab' for all the post R&B style but others reserve that for the early ones which were rather rectangular and use 'modern tab' for the racetrack shaped ones which are still commonly used today.

Regarding cap nomenclature, there isn't a standard but as Badger-NH pointed out, 'crown' are the tradition beer caps which used to require a bottle opener and eventually became scew off as the bottles evolved.  Those tend to dTID in the 20-23 range on the ML Equinox.  They can be made of different combinations of metals so there is no clean target ID.  On the Equinox, there are many tricks to narrow down their identity but there are so many kinds (including rusted versions which TID differently than when they weren't rusted) that one needs to exercise care if you don't want to skip a lot of potentially good targets.  These seem to be a bigger PiTA for beach detectorists because of the Corona generations -- you know, the people that want the effect of beer without the taste.  "Find your beach."  (gag)

The reason 'screw cap' isn't in favor for the older style iron alloy lids is because of the aluminum kind that were used (and still are on some bottles) starting in the 90's (?) on non-returnable glass bottles.  Since plastics have replaced both the bottles and the caps in recent years there aren't nearly as many being discarded but as the originals were aluminum they don't deteriorate easily.  (Wait a couple centuries...)

Here are my nominal digital TID values for the Equinox 800 Park 1, Recovery Speed = 4, Iron Bias F2=0 settings for aluminum pulltabs:

10-13 -- beaver only tabs and some of the smallest unseparated ring-and-beavertail pulltabs.  (Note the overlap with 12-13 of USA nickels.)  Also broken and bent modern (racetrack) pulltabs frequenty hit in the higher part of this range as do severely bent (and broken) ring-only tabs.

13-14 (mostly 14) -- modern (racetrack) pulltabs.

15-17 -- medium sized ring-and-beavertails from 1965-75 drink cans.  Ring only tend to hit in the lower part of this range.

There are various larger pulltabs that come off of Pringles potato chip lids, car fluids containers, etc. which can hit 18 into the low 20's.

And that's just the most common park/school/beach trash in the USA nickel --> Zinc penny region.   Coins are nice in that they are so uniform/consistent in size, shape, weight, composition compared to drink container lids.  Unfortunately in the numbers game the latter have a huge advantage in today's (and yesterday's) selfish & lazy littering society.

 

 

 

 

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