Stompbox friendly RF shield materials, methods?

[Earthscum]

I was curious if anyone had any ideas on different materials that provide the RF blocking, or methods, for the purpose of opening some new ideas in true DIY tradition.

Of course we all know about Aluminum and Steel and Zinc boxes... a couple brass and copper ones out there, as well. What about other box materials?

One idea I've tossed around is laminated composites with a screen mesh embedded. This would provide an additional matrix for support, as well as providing the RF shielding... BUT, I don't know if a mesh will work well enough, or what size mesh would work.

Another idea, using metallic powders in a casting process, but without a proper supporting matrix, this would become brittle. With a matrix, such as fiberglass, I don't think enough powder could me introduced to have a proper effect.

There's this stuff they have at Electronic Goldmine: Ultraperm

What have you used? Do you have any methods for shielding your circuits from the outside world for the purpose of using ABS or Wood boxes? Came across any ideas online that may be worth investigating?

Sometimes I have no problem throwing down a good chunk of cash to make something unique... even if I only make the one. That's the best part of DIY, imagination to reality with your own hands. Lets get some brain juices flowing. I know there are quite a few unique builds on these forums already... if you want to link to those, please do.

[amptramp]

I don't know if it would be available to the DIY market, but a number of display and terminal manufacturers used a spray-on conductive paint loaded with carbon, similar to the aquadag used on CRT's.  Copper foil is expensive but aluminum foil is cheap.  Adhesive copper or aluminum tape is expensive and I remember using a lot of it during EMC (electromagnetic compatibility) testing for aircraft product development and test.  The problem with embedding a mesh screen in fibreglass or any other plastic is that you have to maintain contact at every junction and if the junctions become partially conductive, you may end up with a rectifying junction that could produce intermodulation between RF sources that could upset the circuitry even if it cannot be heard.

[theundeadelvis]

Somewhere there's an article about using magnetic spray paint for shielding. You can buy it at any home center.

[theundeadelvis]

Found it, short and sweet: http://www.muzique.com/lab/magpaint.htm

An example: http://www.amazon.com/Krylon-K03151000-Magnetic-Aerosol-13-Ounce/dp/B000P9BAHI/ref=sr_1_4?ie=UTF8&qid=1313900981&sr=8-4

[Earthscum]

Ok, that's an awesome trick... I don't know how I missed that in so many nights thumbing through that site. Thanks, Ahren. (is that pronounced the same as Erin or Aaron?)

The screen mesh idea would be best done as a single piece. It's not that hard to conform to an odd shape, and you can leave a tab hanging out from an inside corner to ground it out. If making sure all the pieces are touching, that's possibly an option for making your own REALLY odd shaped enclosure. But, how fine of a mesh would you need? Hobby/Craft/Art stores carry an expanded aluminum mesh for making standing forms. Hobby Lobby   Dick Blick (also have copper)

I'm digging that magnetic spray idea.

Are there any machinable composites that have RF shielding ability? I found this site: http://www.eacshielding.com/shielding_composite_products.html, which looks well outside of our price range (haven't checked, though), but still pretty neat.

Also, this abstract was interesting (also interesting that it makes sense to me, lol... 3 years ago I would've been lost and not cared, but now... geek fodder!)

[Earthscum]

Holy crap... check this stuff out! http://www.lessemf.com/fabric.html

[arawn]

real al duct tape available at any walmart for approx. $8. It's amazing how far that stuff will go and the adhesive is conductive so no soldering.

[head_spaz]

Check out some of the ebay items on carbon fiber - woven into fabric

THE SHIT!

[Earthscum]

carbon fiber mats are used the same way that fiberglass matting is. A lot of the CF mats actually have resin embedded in them, so you just have to apply it to the mold and bake it. That's the problem with the stuff, though... you have to cure it. It's a pain in the arse, or else you would see a lot more CF pedal cases.

Now, there are CF panels that could be useful for top plates and such. They are already cured, ready for machining.

I saw that tape. I thought it was a polyester, not real Al, so I always pass it up.

[arawn]

the real stuff is super shiny and smooth

[theundeadelvis]

(is that pronounced the same as Erin or Aaron?)

It's pronounced just like Erin or Aaron. I just happened to named after a firetruck, so I got a funky spelling.   

[iccaros]

Holy crap... check this stuff out! http://www.lessemf.com/fabric.html

We use the "Clear" stuff for windows at work, then we mount  a speaker playing white noise against the glass to block laser.. IT works well, for your needs I am not sure..