Opened my tesoro widescan coil

[cristiano.sar]

Today I opened the bottom of my Tesoro Widescan 11"x8" coil
I removed a layer of a rubber like material (I'm not sure if its resin, but if it is, it is a little flexible) and between this layer and the other (the harder one that contains the coils), there is a thin layer of a carbon like material (maybe graphite), with a resistance of about 9.5k, between a distance of 1.5cm.




I will try to dissect the rest of the coil to see the wiring.

[kt315]

ok. we see some cover, plastic cover, at center of the coil. WHAT IS IT? i answer - ENDED PHASE of nulling process.
after epoxy filling you need still to NULL to 'ideal' coil state. SLIGHTLY yet.
open the cover... look... learn something new guys for yourself...

[kt315]

the plastic cover in a coil. Tesoro tech.

[cristiano.sar]

Thanks! Very interesting.
I opened the cover now, and theer is the final nulling loop.

An interesting thing is that in my coil the loop wire was not glued (it was loose inside the plastic cover), so may be the reason why this coil was beeping on certain movements or simply by touching it.

[kt315]

coil graphite layer somewhere touched a ground, grass or etc. and you get the beeping. you have to shield also a housing (with pcb and batt) inside.

[dbanner]

Yes, check to see if the rx is grounded at the coil end(shield), and put a longstanding question( beeping on wet grass)to rest.

[cristiano.sar]

coil graphite layer somewhere touched a ground, grass or etc. and you get the beeping. you have to shield also a housing (with pcb and batt) inside.

One doubt about graphite shielding, when making our own graphite shielding, do you recommend using commercial graphite paints or making your own?
If making your own, do you have some tutorial of it?
Thanks.

[kt315]

my english does not give me possibility to do tutorials. i write here. yes, i use graphite aerosol but with adding of graphite powder.
this way gives significal economy because the balloon price is expensive (for me). instead 2-3 layers i put just one.
also one layer is cracking after drying.
if you do your own, seek silver powder or make the powder from silver. add it in graphite.

[cristiano.sar]

my english does not give me possibility to do tutorials. i write here. yes, i use graphite aerosol but with adding of graphite powder.
this way gives significal economy because the balloon price is expensive (for me). instead 2-3 layers i put just one.
also one layer is cracking after drying.
if you do your own, seek solver powder or make the powder from silver. add it in graphite.

Thank you so much!

[kt315]

welcome!

[waltr]

One doubt about graphite shielding, when making our own graphite shielding, do you recommend using commercial graphite paints or making your own?
If making your own, do you have some tutorial of it?
Thanks.

I made my own graphite paint.
Used powered graphite mixed into clear polyurethane wood finish. I did a number of different paint products with different amounts of graphite powder.
Painted onto a piece of cardboard and choose the one that gave a consistent resistance measurement. I think it was about 1-5kOhm at 1 cm with DMM probes.

Used this on the DD coils for a TGSL. Each coil wound then wrapped with electrical tape. A very fine wire then spiral wrapped on each coil and not connected as a loop.
Painted over with the graphite mixture. After drying wrapped with another layer of electrical tape. This keeps the shield lay on each coil from touching. The thin 'drain' wire then connects to the coil cable to the TGSL's ground.

I have read that Guitar shield paint works well but it is pricey.

[cristiano.sar]

I made my own graphite paint.
Used powered graphite mixed into clear polyurethane wood finish. I did a number of different paint products with different amounts of graphite powder.
Painted onto a piece of cardboard and choose the one that gave a consistent resistance measurement. I think it was about 1-5kOhm at 1 cm with DMM probes.

Used this on the DD coils for a TGSL. Each coil wound then wrapped with electrical tape. A very fine wire then spiral wrapped on each coil and not connected as a loop.
Painted over with the graphite mixture. After drying wrapped with another layer of electrical tape. This keeps the shield lay on each coil from touching. The thin 'drain' wire then connects to the coil cable to the TGSL's ground.

I have read that Guitar shield paint works well but it is pricey.

Thanks! I will try that mix.

[dfbowers]

I purchase "guitar shielding paint" from ebay.
It's a water-based carbon paint that is cheap and very conductive. It's also thick enough to attach wires to the paint.

[kt315]

do not run for low resistance of the carbon layer. you have to get only some ability to discharge of accumulating surface charges sufficiently fast.
also, measuring of the resistance is not correct be cause acting voltage reaches a value in 10000+ V (10kV +) while you use a tester with just 9V battery.

.

[cristiano.sar]

I purchase "guitar shielding paint" from ebay.
It's a water-based carbon paint that is cheap and very conductive. It's also thick enough to attach wires to the paint.

Nice coil.
One doubt, the strip that is not painted is really needed? Even if I use a DD coil? I'm asking that because I can't see that strip for example in a Minelab commander DD coil.
Thanks.