conductive paint

[simonbaker]

Any thoughts about these interesting looking products?

-SB

http://www.action-electronics.com/conductivepaint.htm

Super Shield Conductive Coating-Reduce or Eliminate EMI / RFI Interference
A general purpose EMI / RFI shielding spray for use on plastic electronics enclosures. Consists of a tough, durable acrylic base pigmented with a high purity nickel flake. Approx. 1600 Sq. Inch coverage. Shielding effectivieness: One to two mil coating provides 40dB - 50dB shielding across a frequency range of 5 to 1800MHz. Surface Resistance approx. 0.7 Ohms - Dry time: 10 minutes at room temperature - Recoat time: 5 minutes - Excellent adhesion to most plastics - Available in both liquid and aerosol - Tested as per IEEE Std. 299-1997 - Underwriters Laboratories Recognized File No.: E202609 - Liquid version available for dipping, brushing or spray gun applications. - Thinner is available for adjusting the viscosity - NO CFC 'S, NO HCFC'S, Ozone Friendly
[Restrictions-No Air Freight, No Export] [MSDS MG-841-340G]

841-340G 12 oz. Spray

$29.90

[hobbes_lives]

I just posted about the same stuff in another thread...

http://www.geotech1.com/forums/showp...4&postcount=23

[simonbaker]

I just posted about the same stuff in another thread...

http://www.geotech1.com/forums/showp...4&postcount=23

Hah, coincidence!

Actually, maybe not resistive enough for our best use.

Cheers,

-SB

[B^C]

Hah, coincidence!

Actually, maybe not resistive enough for our best use.

Cheers,

-SB

Gday Simon,

You need at least 100 ohms per sq/in, use "Aquadag" as suggested it's on the money. It goes a long way so it's cheap per coil.

[Tinkerer]

Gday Simon,

You need at least 100 ohms per sq/in, use "Aquadag" as suggested it's on the money. It goes a long way so it's cheap per coil.

This looks indeed like an excellent shielding product
http://en.wikipedia.org/wiki/Aquadag

Tinkerer

[Max]

This looks indeed like an excellent shielding product
http://en.wikipedia.org/wiki/Aquadag

Tinkerer

Hi,
yes, indeed it is. It's old stuff... graphite powder... really fine powder and colloidal suspension in a water solution (with add of particular additives needed). Really it's not so cheap to buy cause it's sold often in large cans (and you need few for coils) and if I remember well there's something 2 or 3 pounds of graphite per gallon of solution... so it's well "loaded" with colloidal graphite particles.

In past it was employed on crt screens too but had a number of applications and one really interesting to us is about shielding of rf apparatus (well before the introduction of nickel spray and similar things).

I'm still looking for a good recipe to make it at home... cause I have pure graphite in good quantity but seems that it isn't any good source of that cause , simply, particular machines and process are required to obtain the colloidal solution. I found that tannic acid help provide colloidal dispersion of it... but last time I try don't get required results....that's furstrating.

Someone tested some laquer and graphite powder with acceptable results but are just cases cause it's not easy obtain always same colloidal solution with commercial laquer base...

It's like with silver : same stuff.... you'll find acetone based laquers with silver.... but all is about colloidal solution not just that silver is in solution.... too big particles are not good there. Same for copper too.

Kind regards,
Max

[B^C]

Hi Guys,

The Aquadag does really go a long way for this application, for coil shielding if you apply it by brush basically the thickness of the coating is to heavy & you have a lot of waste.

Because it is well loaded with Graphite,
One or two "good" coats with a small spray gun is plenty, the coating only has to evenly cover the cardboard with no obvious thin spots.
A coverage of .002" dry is plenty, just make sure you have a good overlap when spraying to avoid the thin spots. Spray one way & then at 90deg to it.

If your suppliers only have gallon tins which would do a couple of hundred coils or more, you can ask them who purchases a lot of it. Once you find this out just contact then & i am sure they would sell you a small amount.

Don't forget most suppliers can get sample tins from the manufacturers.
The first lot i got was a 1ltr tin as a SAMPLE from a supplier, i told them i wanted to test it out to see if it was suitable before purchasing bulk quantities.

[B^C]

I did a bit of a search & it seems that small quantities of Aquadag are available.

http://www.technologysupplies.co.uk/...nt_342144.html

http://www.laddresearch.com/General_...ng_paints.html

[Rov]

any links to Aust.suppliers mate.got a couple of custom made coils done in this from Victoria ,Aust. just gotta get some blank hayes housing for them.an Pot!
But would like to try some home wounds myself,with patience? thanks!

[B^C]

Gday Rov,

No worries, try these guys

http://www.acechem.com.au/A.html

ACE CHEMICAL COMPANY
119A Mooringue Avenue
Camden Park
SA 5038


Phone: 08 8376 0844
Fax: 08 8295 8563
Email: [email protected]

[Rov]

Thanks very much for that Link,yes local same State.
What Quantities should I be requesting of them for a few home built coils,do they do a minimun Quantity?
Doesnt matter will ask them direct,now i have the Link.
Cheers! appreciate!
Rov

[nick_f]

Hi Rov,
If you get some aquadag, please let me know. At the moment I bought some Scotch24 shielding tape, it has yet to arrive. I am also interested to get some housing coils. I find the freight from USA quite expensive when ordering cheap parts (like $15 for parts and $15 or even $30 for shipping). I am in Sydney, maybe we can order some parts together, to split the costs.

Regards,
Nicolae

[Rov]

Hi nick f, I havent got my aquadag,yet.I intend to pick some up on a visit that way later to the SA. supplier,but not just yet.
Have you tried the Scotch adhesive foil tape as used in TV de-Gauss coils that is used by some?
I tried untape/unwind the Foil tape of a late model SanyoCRT Coil to see what it was,an was the same as a roll of scotch Foil,thin an low tack adhesive.an easy to use.
I intend to give this a try on future coil builds as I have a roll of it to try.
But again later,as have too many other m,detector PCB projects on the go with errors!re-the CS6pi project build.
I appreciate your offer tho,for share expenses on parts imports cost.will keep in mind.Thanks!
As to coil housings,eg. as from hayes usa. will ask Pennyweight as he has supplied me some local here in australia,an he is in the know!
Cheers! Rov

[nick_f]

Hi Rov,

I haven't tried the Scotch adhesive foil tape. I just ordered from USA some Scotch24 shielding tape, I hope I will receive it within 2 weeks.
I used adhesive aluminium foil until now, it works, but at this stage I strive to build some fast coils.
At the moment I just measured two coils with teflon, I described the results in http://www.geotech1.com/forums/showthread.php?t=15383

Please check with Pennyweight if he still has some coil shells available.

Regards,
Nicolae

[bklein]

Hah, coincidence!

Actually, maybe not resistive enough for our best use.

Cheers,

-SB

Did anyone actually try this stuff?
I have a bunch in my lab at work.
I did some work on a Minelab coil that caused a few tears in the shield. I applied super glue to join the tears and sprayed a bit of this over the repaired areas. Ok?
We have like 5 cans of this stuff....