Chance PI coil...

[baum7154]

That would be my guess too Chet.

[Chet]

Hi Dan
Interesting results, maybe the lump shape of the aluminum cylinder keeps the eddy currents circulating a little longer and stronger.
Have a good day,
Chet

[baum7154]

Today I took the latest oval 'racetrack' coil detailed in posts 215 & 216 of this thread out to the yard to do a test of detection distance with the coil laying on clean damp ground. I used three targets to simulate small gold and they are:

0.7 grain aluminum cylinder of 1/8" diameter and .09" long…this simulates a 5 grain piece of gold by volume.

A 1/2" X 1/2" X 0.004 thick square of aluminum soda can.

A 1/4" X 1/4" X 0.004' thick square of aluminum soda can.

All of these were test detected in air before.

The detection results for full repeatable tone lockup of the targets is as follows:

0.7 grain AL cylinder----1.5"---------------Air test distance 1.75"

1/2" X 1/2" AL square----4"----------------Air test distance 5.375"

1/4" X 1/4" AL square----3/4"--------------Air test distance 1.75"

Don't know why the thin flat targets had greater detection distance loss than the 1/8" AL slug.

Regards,

Dan

[kellogs]

Hi solmer2 are you new to this hobby as well i will try to help but all members are really help fully chet and baum7154 are the ones helping me there is a post by buy baum 7154 post 126 in chance pi coils any way this is what i have used lexan plastic .96 mm and used the suggested wire by chet and baum7154 and my coils work great iam now reading up on fine tuning my surf pi if you read through the chance pi coils postings mate you will gain a lot of help if i can help let me know Kindest Regards kellogs

[Sean_Goddard]

Hi thanks for your help,

While searching the web I've found a printable for the ultra fast coil as well as detailed info about building the coil.... now I need to find a suitable material... (cardboard is a bit soft and I don't like to made it of wood so I'll try to get a piece of plastic.....)

Thanks again.

TUFNOL

[Chet]

Hi baum7154 your coil looks great you have done a great job hop it works well for you i went looking for coil housings but have decided to make them my self i have made my vacuum form box not a big one 16''x16'' and am waiting for my form sheeting which is local hear in Aus.Mate i was wondering if you or chet have any ideas about vamping a surf pi i was just wondering any way all ways good having a chat i will have to learn how to attach photos to my posts hope this finds you both well talk later Kindest Regards kellogs.

Hi Kellogs
I haven't had any experience with the Surf PI. I am interested in how the coil forming works out.
Regards,
Chet

[Qiaozhi]

i will have to learn how to attach photos to my posts hope this finds you both well talk later Kindest Regards kellogs.

After you start a new post, click on the "Go Advanced" button. Then scroll down the page, and you'll see "Manage Attachments".

[baum7154]

Hi baum7154 your coil looks great you have done a great job hop it works well for you i went looking for coil housings but have decided to make them my self i have made my vacuum form box not a big one 16''x16'' and am waiting for my form sheeting which is local hear in Aus.Mate i was wondering if you or chet have any ideas about vamping a surf pi i was just wondering any way all ways good having a chat i will have to learn how to attach photos to my posts hope this finds you both well talk later Kindest Regards kellogs.

---------------------

Hi Kellogs,
It is very resourceful of you to make your own vacuum forming rig and I'm sure will use it for all kinds of things for years to come. I have no experience with the Surf PI so I guess I'm not much help to you. Thanks for the kind words on my my new oval coil. There will be ongoing posts on its construction to completion.

Best of luck on your projects.

Dan

[kellogs]

Hi baum7154 your coil looks great you have done a great job hop it works well for you i went looking for coil housings but have decided to make them my self i have made my vacuum form box not a big one 16''x16'' and am waiting for my form sheeting which is local hear in Aus.Mate i was wondering if you or chet have any ideas about vamping a surf pi i was just wondering any way all ways good having a chat i will have to learn how to attach photos to my posts hope this finds you both well talk later Kindest Regards kellogs.

[baum7154]

One more picture of the whole coil.

[baum7154]

Attached is a photo of my oval 4" X 12.5" coil showing the Lexan form with 28 turns of 24 AWG, 600 volt PTFE stranded wire yielding 328 uh and a SRF of 965kHz with 37" of twisted pair feed that is just a continuation of the coil winding and twisted at a rate of 2 to 3 turns per inch. The feed line sheathed with 2 layers of 1/8" shrink tube and the coil end has 2 additional layers of 3/16" shrink as reinforcement to snugly fit into the neoprene cable fitting not yet shown. The exposed wire end with the red heat shrink indicates the innermost wire end that must be tied to the hot or high side of the detector coil connection. More construction photos to follow as the build continues.



Dan

[mickstv]

Hi mickstv sorry mate yes as usual didn't check my typing yes i ment 15cm just imagine if some one came up with a detector to detect 150cm.As i am not a teco but used to do a lot of deep sea fishing over hear and had a lot to do with fish finders and depth sounders why or how the same technology couldn't be used in the design of metal detectors our am i just that silly.any way thanks for your input as well i have watched your post and you help is valuable to all us new members have a great day Regards kellogs.

Hi kellogs, thats ok mate. Imagine trying to dig a hole that deep anyway, it would take days by hand.

[kellogs]

Hi mickstv sorry mate yes as usual didn't check my typing yes i ment 15cm just imagine if some one came up with a detector to detect 150cm.As i am not a teco but used to do a lot of deep sea fishing over hear and had a lot to do with fish finders and depth sounders why or how the same technology couldn't be used in the design of metal detectors our am i just that silly.any way thanks for your input as well i have watched your post and you help is valuable to all us new members have a great day Regards kellogs.

[mickstv]

The reason I asked was, that I find it hard to believe you could detect a dollar coil at 150cm (nearly 6 foot) deep, are you sure you don't mean 15cm ?

[kellogs]

Hi mickstv as i am only new to this hobby chet and baum7154 have been such a great help i have just followed there advice with the original 8'' od 6''id coil with a basket weave the only difference is i wound plumbers tape after every five turns.Wound 40 turns first and removed until i had the best results with alloy foil 1/2x1/2x 1/8 hope this is some help i have 2 more weeks and i am able to star walking on my leg have a great day Kindest Regards kellogs