Shielding with sticky aluminium foil

[nick_f]

Hi All,

It seems that I discovered a method for using aluminium foil to shield coils and still to obtain a good sensitivity to small gold (or any other targets with a low Time Constant).
The solution is simple and many of us would be actually aware of it. In order to transform a piece of aluminium foil (for example 1 inch x 5 inches - very easily detectable by a metal detector) in stealth aluminium foil, all we have to do is to divide it into thin slices. I tried with 5mm slices and now my detector can't see it at all. The length of the slice doesn't matter, as long as it is thin.
So, there is no problem to use aluminium foil for shielding, as long as you are patient and use slices 5mm in width (the narrower, the better).

They should be electrically isolated one from the other on their length and joined only at one end, where they are connected to ground.
The capacity of the shield is a different story, and Scotch24 might be better in this respect. Not sure about Aquadag and Nickel spray, I think they would still have higher shield capacitance compared to Scotch24.

Regards,
Nicolae

[simonbaker]

Hi All,

It seems that I discovered a method for using aluminium foil to shield coils and still to obtain a good sensitivity to small gold (or any other targets with a low Time Constant).
The solution is simple and many of us would be actually aware of it. In order to transform a piece of aluminium foil (for example 1 inch x 5 inches - very easily detectable by a metal detector) in stealth aluminium foil, all we have to do is to divide it into thin slices. I tried with 5mm slices and now my detector can't see it at all. The length of the slice doesn't matter, as long as it is thin.
So, there is no problem to use aluminium foil for shielding, as long as you are patient and use slices 5mm in width (the narrower, the better).

They should be electrically isolated one from the other on their length and joined only at one end, where they are connected to ground.
The capacity of the shield is a different story, and Scotch24 might be better in this respect. Not sure about Aquadag and Nickel spray, I think they would still have higher shield capacitance compared to Scotch24.

Regards,
Nicolae

Can you show a picture of what you mean?

Regards,

-SB

[o.mag]

hi
Another possibility for the shield is a survival blanket.
some on the aluminum layer is sufficiently conductive
that I use is olive green color

olivier

[nick_f]

Can you show a picture of what you mean?

Regards,

-SB

Hi Simon,
Sure I can. Please check the photo. You need to cut a strip of aluminium 5mm in width and to spiral it around the circumference of the coil, as neat as possible, leaving a small space between turns, to prevent shorting. Then one end of the shielding has to be connected to the ground, as usual (for long term results, soldered under an oil layer). I haven't tried this method, but I am confident it works. If anybody tries it, please let me know the results.

Olivier's method is very ingenious and it deserves a try. I don't have any survival blanket around to do some testing.

Regards,
Nicolae