Magnetic decay of gold verse lead

[Newbie]

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Michael, did you try to detect aluminum foil or aluminum can? Did you start with 1/4" X 1/4" square of the aluminum? If so you should probably start with a 1" X 1" square of the can and work your way down in smaller size squares until you can no longer see them. If you cannot see a 1" X 1' piece of can then try a whole aluminum can. Foil is 3 to 4 times faster and more difficult to see so don't start with the foil.

The number of turns was determined in my coil by winding a coil of more inductance than needed and measured with an inductance meter. Then I took one turn at a time off of the coil testing small gold/aluminum targets as I went and found the that the best performance for my detector and coil was 32 turns. This measures 335uh with the meter. Generally though, about 300uh is used in searching for small gold. That would be about 30 turns on an 8" coil. You can use the coil calculator that QUIOZI has posted as a sticky at the top of this forum to determine how many turns will equal 300uh.

If you want to build the spider coil I use I have documented it extensively in the CHANCE PI COIL thread of the COILS forum. You should read the whole thread if you have not already done so. The exact recipe is there along with photos of the build, test results, and CHANCE PI detector info. That coil should work well with any PI detector and is quite fast. The most difficult part is making the Lexan coil form but it can be done with hand tools and careful attention to fabrication. The use of 600 volt PTFE/Teflon insulated stranded 26awg wire is required for best results. This coil built with enameled solid wire will result in disappointment, trust me I have done it.

Best of luck,

Dan

Hi Dan I went the can cut into 1/4 x 1/4". the surf did not see it but I have made a faster coil that can see the wedding band at 9" on a 6" coil, still can't see 1/4 x1/4" can but heading in right direction. Just wound another coil hopefully a little faster.

Michael

[baum7154]

Hi Dan I went the can cut into 1/4 x 1/4". the surf did not see it but I have made a faster coil that can see the wedding band at 9" on a 6" coil, still can't see 1/4 x1/4" can but heading in right direction. Just wound another coil hopefully a little faster.

Michael

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Good progress Michael. What kind of fast coil did you wind? Is your coil shielded and if so with what material? I would cut some larger pieces of pop can targets. Perhaps a 2" X 2" piece or even a 3" X 3" would give an intermediate size that your detector can see. Were you able to adjust your sample delay to a shorter time? Keep in mind that if you are able to see the small aluminum targets that you will also get more falsing in wet saltwater sand. Also you may need to adjust TX pulse width for optimum target response per BB SAILOR's post above depending on target size and composition.

Dan

[Newbie]

http://youtu.be/deU1nXqYkBg

Just a quick video showing results. I am happy with the out come but there is always room for improvements, I have taken about 6" off the coax since shooting video