EMI Shield Spray for Search coils?

[Nupi]

I used regularly water resistant sandpaper grit 600 painted with diluted blackboard paint.

The links contain very interesting details, thanks.

[Chet]

Some more information on shielding;

http://www.geotech1.com/forums/showt...793#post195793

Have a good day,
Chet

[6666]

I used regularly water resistant sandpaper grit 600 painted with diluted blackboard paint.

The links contain very interesting details, thanks.

Hi Nupi are you useing the 600 grit sandpaper to lightly sand the surface of the blackboard paint ?

[6666]

Some more information on shielding;

http://www.geotech1.com/forums/showt...793#post195793

Have a good day,
Chet

Thanks for digging up that thread, forgot about that one.

[Nupi]

Hi Nupi are you useing the 600 grit sandpaper to lightly sand the surface of the blackboard paint ?

I use the sandpaper as a base for the paint.

[Point]

Thanks Don and Point, just found a possible supplier of 8GS,here in Australia, it will probably be $100 a can by the time the USA to Aus dollar conversion and the "Australia" tax is added
just sent them an email, be interesting to see what they say. Probably have to buy it by the box full.

Point from pictures I've seen of Cat7, it has heavy internal shielding, be interested in how it works for you.

ok first test finish...
10% leser noise again cat7 without graphite. arround 40% lesser without any shield still testing with breadboard and it make alot noise... i will replay how its them after soldering on plate. But right now 555 goldring outer radius 20mm strenge 0.6mm 13cm true detection on 160mm coil its still not much but better thats my first one who dont ever have detect the goldring
oh btw. my frequency is right now really low 2.2khz ~ 400-500us loops. and the software are still on alpha status

[6666]

Just doing a chalkboard paint test, waiting for it to dry 4-6 hrs, did not dilute it just painted on to thick cardboard, ground wire included.

[6666]

Well the first test with the black chalk board paint is a failure not conductive at all.

[Nupi]

Well the first test with the black chalk board paint is a failure not conductive at all.

I do not know what some sort paint you used. Polyurethane acrylate, Latex,....?
Dry in 4-6 hrs is fast!
The paint that I use dries in 24 hours at 20 degrees Celsius.
A known gave me the tip of chalkboard paint. It is also used as anti-reflection paint in optical systems under a different product name and price !! It would contain carbon and graphite.
On the PDF from the product says, Based on alkyd resin and slate flour?!?!
But of course, the manufacturer do not give his recipe away.
I've tried it and it works great. For me, better than graphite paint.

I use it on all my coils (including prototypes).

flexa-schoolbordenverf.pdf

[SVEN1]

I decided to try something different as a coil shield. So far it appears to work.
Referencing back to my first post.
The DD coil rec'd was first sprayed with carbon shield paint, the coil was placed into position, nulled and tack glued in place.
One wire from the coil shield... was ground to the shell itself, tacked in place a 2" piece was left straight up.
I proceeded to do the first pour of epoxy. Let it semi cure. Bought some thin carbon fibre tape, epoxied it in place over the first pour using 5 minute epoxy.
a few inches at a time.
The carbon tape does not touch the coil shell sides but goes around the inside perimeter of the coil. The ends do not touch, left a gap.
The wire sticking up from the coil shell bottom is then grounded to the carbon tape and secured with a very small piece of copper foil tape with conductive adhesive.
Pressed down securely to make sure full contact with the carbon fiber tape. A dab of 5 minute epoxy to seal it from the topside.
Finally I made the final pour. This now encapsulates the the carbon fiber tape within two layers of potting epoxy. Will not be worrying about the two layers of epoxy separating
in the future.

This was an experiment, right now a quick bench test shows the coil works great.

[IMG][IMG][/IMG]
[IMG][/IMG]

[6666]

I do not know what some sort paint you used. Polyurethane acrylate, Latex,....?
Dry in 4-6 hrs is fast!
The paint that I use dries in 24 hours at 20 degrees Celsius.
A known gave me the tip of chalkboard paint. It is also used as anti-reflection paint in optical systems under a different product name and price !! It would contain carbon and graphite.
On the PDF from the product says, Based on alkyd resin and slate flour?!?!
But of course, the manufacturer do not give his recipe away.
I've tried it and it works great. For me, better than graphite paint.

I use it on all my coils (including prototypes).

[ATTACH]35887[/ATTACH]

Hi Nupi, thanks for that info I tried this paint very disappointed it did not work must be different recipe
http://www.bunnings.com.au/white-kni...paint_p1566487

[Nupi]

Hi Nupi, thanks for that info I tried this paint very disappointed it did not work must be different recipe
http://www.bunnings.com.au/white-kni...paint_p1566487

Hi 6666,
I am sorry for you that you can not use the paint.
It is clear that my paint has a different composition than yours.

[6666]

Hi 6666,
I am sorry for you that you can not use the paint.
It is clear that my paint has a different composition than yours.

Hi Nupi its not your fault, just different manufacture, there is one more brand in my town that I could try, I tried looking for your brand, but it looks like they do not export outside Europe.

[kt315]

thank you graphite spray is expensive or do you know where buy it cheap?
have you tried the poor mans sheilding?
the inside of a carbon battery mixed with paint?

[6666]

thank you graphite spray is expensive or do you know where buy it cheap?
have you tried the poor mans sheilding?
the inside of a carbon battery mixed with paint?

Hi KT315, I have made good graphite paint useing powdered graphite used for locks bought from a hardware store, and wood varnish
also I have some manganese dioxide from the inside of a heavy duty zinc carbon d cell, but I have not tried it yet