Broken Ring Test

[harvdog42]

The other day a buddy eyeballed a little gold ring in the sand. (2.2 grams 14K tested) To his surprise his detector would not hit on it. He uses a Whites Surfmaster with one of those huge coils.

He brought the ring over to the house and I noticed the weld was broken. That explained a lot but I thought for sure my Tesoro Sand Shark with the 8" coil would hit it. I was wrong and would have lost that bet.

Then I tried my Cibola and got only the faintest response even at point blank range. Then I broke out my old Fisher 1265 and it sounded off much better than the Cibola which was a surprise but was still a faint signal.

Then we took a tiny bit of foil and completed the "circuit" of the ring at the broken weld. All the detectors hit on that thing easily and from a respectable distance.

Just thought I would throw that out there.

Harvdog

 

[Magicman]

We talked about that in Daytona at the shootout. Tom Dankowski explained why this happens. I did not take detail notes on the the reason why it happens, however I am sure I can find out if you want to know.

 

[JOHNMARKHAM]

its because theres no complete circuit!!

 

[Gulf Hunter]

Hey Harvdog, seen a couple of examples of this recently myself, but on gold earrings. In one instance, I had a penny hit on the Excal and upon digging the penny, there was a 10K gold hoop earring in the scoop, as well. The clasp was open on the earring and I ran it under the coil on the Excal and NOTHING! I closed the clasp and BOOOP! In another recent hunt, got another penny signal and upon digging the penny, noticed that something yellow and shiney was snagged onto some plastic in the lane. I dug the penny and pulled the nice looking morsel loose from it's snag. It was a section of a broken gold hoop earring. I ran it under the coil and NOTHING. That's OK, because I got it and even though it was not stamped, the acid test revealed it to be 10K, so I'm good with it. I have recovered some broken rings though, but they were still attached together, just fractured. It would probably would make us ALL cringe to know what we have passed over out there at one time or another. Perhaps it is best we don't know, LOL!

 

[tvr]

do a search on eddy current and a lot of technical stuff turns up about what things like laminating and slotting or breaking of loops do to affect things.
tvr