XP GMP does 6" buried bolt at 8" still sound like iron?

Hi guys just wondering for those using a XP GMP how does the detector handle these large rusty bolts (about 1/4" thick) buried at about 8" deep.

Will the GMP pick these up as a "normal target like a coin" due to the depth or will it still recognise the rusty bolt and treat it as iron?

Thanks in advance.

Joe

Joe from Aus
CZ3D, G2, Garrett Sea Hunter M2



Edited 3 time(s). Last edit at 06/11/2014 01:05PM by wolfau.

I just tried the test you asked for. I used a three eights by two and half inch bolt somewhat rusty and buried it 8 inches down in my very dry medium mineralized Arizona dirt.

With my 11 inch coil in Deus fast mode I got ID numbers of 97 to 98 - or nothing, with occasional darkening of the horseshoe the upper right-hand or nonferrous corner and a high tone with occasional iron grunts. I did notice that the iron grunts were more common when I swept across the axis of the bolt, when I swept along the axis of the bolt I got only high tones but they were very broken and kind of double quite unlike a coin signal.

I then tried the GM power mode this was quite different. Now I was getting a lot more iron grunt - readouts of 97 to 98 with occasional readouts of 1 or 3 and the horseshoe was darkening in the upper left-hand or ferrous quadrant.

I then went back to the Deus fast mode and reduced the reactivity from 3 to 1 - this way I got approximately the same results I had gotten in the GM power mode.

The same bolt in air testing gave me clear iron readouts in the ID in both modes at the same 8 inch distance.

Hope this helps it sure was hard to dig in that red Arizona dirt with rocks everywhere.

Rick Kempf
Gold Canyon AZ- where there is no gold

HI Rick thank you so much for the test.

MIneralised ground is a bugger to dig through I understand that because I do some prospecting.

Thanks AGain
Joe

Well, I had some help, lizards had some holes in the area and it was a bit less crusty than the usual. I don't think it affected the results however.

Rick Kempf
Gold Canyon AZ- where there is no gold

Take one of your old rusted bolts that you have already found , reburied it in your test garden. I do this with square nails, and other thrash. More realistic then a fresh bolt or fresh nail.

I have a clean test garden and a thrashy test garden.

The bolt I used was a "found object". Stuff doesn't rust very fast here. A hundred year old railroad spike (heavily rusted) showed the same general behavior.

The key finding here is that increasing the reactivity reduced the ability to correctly identify the bolt.

Rick Kempf
Gold Canyon AZ- where there is no gold



Edited 1 time(s). Last edit at 06/12/2014 01:18PM by lytle78.