Monday, March 19, 2012

3/19/12 Report - Tumbaga Bar & Detecting Watches

Written by the Treasureguide for the exclusive use of

10 Pound Tumbaga Bar in Current Sedwick Auction

This bar currently has a bid of over $4000 and the auction has just begun.

In the very early days of Spanish exploration in the New World, Native American artifacts were melted down for transportation back to Spain. The melted materials were often cast into bars that varied widely in the amount of gold and other metals. These melted metals were referred to as Tumbaga.

In a Tumbaga bar there might be as much as 97% gold or there might be as much as 97% copper. Mixtures of gold and copper containing a lot of copper can be very brittle and will easily break.

I still think that IF Spain can claim the treasure of the Nuestra Senora de Las Mercedes after it was recovered by Odyssey, that the native American groups actually have a more just claim.

In my last post I was talking about watches. I mentioned that detectors might have a tough time identifying a watch. Watches come in a lot of varieties and I don't know how you could expect a detector to correctly identify a watch.

I also mention from time to time that it is important to know your detector and how it responds to different situations and different targets.

I decided to do a little experiment.

I took three watches. The first is a small cheap women's watch, like a Timex. It has a non-metallic band.

The second watch is a large men's Seiko.

The Third is a rather typical dive watch.

I chose an Excalibur for the experiment since it is a commonly used detector on the Treasure Coast. I set the Excalibur on discriminate mode. Then I set the discrimination setting on 15.

Then I swept the coil over all three watches. As you might expect the high discrimination setting resulted in a relatively small signal on all of the watches. Using that high discrimination setting you could easily miss all three watches.

In this experiment, the dive watch gave virtually no signal when the detector had this high discrimination setting. The others gave some signal.

These watches are not buried either, and I was sweeping only about four inches over the watches.

Then I moved the discrimination setting back to about 10. As you would expect, the signals were then stronger, but on some watches still weak.

Then I set the discrimination on 1, and as you might guess, the signals were better. You probably would be able to detect all four watches easily with this setting in field conditions.

I had a video of the experiment but was having trouble with the link and took it out.

How the watch lays is also important.

If the coil is angled to detect more of the face of the watch you will generally get a louder signal, but watches generally don't lay flat in the sand unless the band is not present.

If a metallic band more squashed together rather than being in an open circle you will get a signal something more like a spike or some long elongated object.

I highly recommend that you experiment with your detector and different objects under different circumstances. Learn the different sounds and what they are telling you and learn the effect of different detector settings.

If you experiment enough, you can get a good idea of the size and shape and depth of an object from the signal.

The more variations you try and the more you experiment, the better off you will be.

If you come across a nice watch or anything nice, you don't want to be fooled by your detector. A lot of good objects are missed because of too much discrimination or too much reliance on the detector's target ID.

As I've said before, I usually use pinpoint or all-metals mode on the beach no matter what detector I am using.

If you really know your detector, pinpoint mode will generally yield the information you need to determine the size, shape and depth of the object, as well as some information about the composition of the object.

Well, beach detecting conditions on the Treasure Coast remain pretty much the same. I don't see any significant changes coming for the next few days.

The wind is pretty much from the east and the seas running around four or five feet.

Nothing promising.

Happy hunting,