Spray shield paint aka graphite - Page 1
Forum section: electronics / projects

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 29, 2020, 06:02:24 pm
content: Does anybody know where a reasonably priced < $20.00 spray shield paint aka graphite is sold?Searches on Amazon are of the most annoying as it does not recognize -words and even a sort by price is useless.I want to do some shielding on a project to keep RF out. I could do the copper tape stickum trick but it gets messy and is wasteful.I see the MG Chemicals can for $40+ and that's just not right.Any ideas on where?

author: madires
author_rank: Super Contributor
timestamp: September 29, 2020, 06:11:41 pm
content: Graphit 33, or better use EMV 35 (more expensive).

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 29, 2020, 06:29:54 pm
content: I'm in the US. Is that a product available here? A search reveals only golf clubs on eBay.I just don't see anything over here...It's all to do withLEAD!!!!!LEAD!!!!!!LEADHow did the world ever get this far without the lead scare.Where's the stuff these folks used back in the day. Probably cost pennies....Quote from: madires onTodayat 03:11:41

author: madires
author_rank: Super Contributor
timestamp: September 29, 2020, 06:43:04 pm
content: Then better change your country to US.https://www.crcindustries.com/where-to-buy/

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 29, 2020, 06:48:49 pm
content: They have no reference to Graphit 33 only lubrication products.

author: hendorog
author_rank: Super Contributor
timestamp: September 29, 2020, 07:04:04 pm
content: Does that approach work?Hard to see a thin layer having very good conductivity compared to copper.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 29, 2020, 07:26:22 pm
content: It gets int every nook and cranny that copper foil would not. It's not about passing current, just an RF shield.

author: ucanel
author_rank: Regular Contributor
timestamp: September 29, 2020, 08:30:32 pm
content: Not the thing that you are looking butthis is a cool way to coat something with metals.https://youtu.be/9OEz_e9C4KMhttps://youtu.be/Cyu7etM-0Kohttps://youtu.be/Cyu7etM-0Ko

author: Bud
author_rank: Super Contributor
timestamp: September 29, 2020, 08:43:25 pm
content: It is cool but totally not practical.

author: eliocor
author_rank: Unknown
timestamp: September 29, 2020, 09:28:53 pm
content: Search for "colloidal graphite" or "aquadag"You can also use:https://electrolube.com/product/nscpnickel-screening-compound-plus/https://www.tme.eu/Document/3a4dc9b13d1c7d13f1a935cd3db9778e/NSC%20%20_en.pdf

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 29, 2020, 09:38:22 pm
content: https://www.amazon.com/ELECTROLUBE-NSCP400H-Conductive-Coating-AEROSOL/dp/B06W548Z9QNSCP400H Only $63.00 per canI'll look for it laterQuote from: eliocor onTodayat 06:28:53https://electrolube.com/product/nscpnickel-screening-compound-plus/https://www.tme.eu/Document/3a4dc9b13d1c7d13f1a935cd3db9778e/NSC%20%20_en.pdf

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 29, 2020, 09:45:49 pm
content: Totally over priced! But as the man said cool.I think Glasslinger did a few sputtering experiments,Quote from: ucanel onTodayat 05:30:32

author: eliocor
author_rank: Unknown
timestamp: September 29, 2020, 09:50:57 pm
content: Yes, NSCP400H is expensive, but its RF shielding properties are much better than colloidal graphite:http://www.acsu.buffalo.edu/~ddlchung/Improving%20colloidal%20graphite%20for%20electromagnetic.pdfhttp://davidlu.net/13869667.pdf

author: amspire
author_rank: Super Contributor
timestamp: September 29, 2020, 10:27:13 pm
content: Black Acrylic artist ink is conductive. The resistance is a bit too high on its own but it can be copper plated after application using a piece of scrap copper and a copper sulphate from the hardware or one of the copperless plating solutions (often a bit of acid like vinegar, salt, sometimes antifreeze). A just did a test and a 1cmx2cm patch of acrylic ink on plastic had a resistance of about 8K.

author: thm_w
author_rank: Super Contributor
timestamp: September 29, 2020, 10:51:50 pm
content: https://www.eevblog.com/forum/projects/emi-spray-experience/https://www.eevblog.com/forum/projects/prototyping-rf-shielding/https://www.eevblog.com/forum/chat/esd-ifying-plastic-containers-with-conductive-paint/https://www.eevblog.com/forum/beginners/emi-shielding-a-plastic-diy-electronics-box-(al-foil)/

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 29, 2020, 11:05:09 pm
content: Interesting links. The ones that are helpful (or not) are the ones that referenced Zinc Copper and Aluminium paint.I don't know how well they would perform though.

author: madires
author_rank: Super Contributor
timestamp: September 30, 2020, 08:44:47 am
content: EMV 35 spray is copper and provides shielding >60dB.

author: BravoV
author_rank: Super Contributor
timestamp: September 30, 2020, 09:03:40 am
content: In Europe and Asia, Kontakt Chemie is quite popular, and for that purpose Graphit 33 is enough as I used before at similar purpose, also its really good for repairing silicone membrane switch at remote.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 30, 2020, 09:20:40 am
content: Still no help here in the US

author: Mechatrommer
author_rank: Super Contributor
timestamp: September 30, 2020, 10:29:50 am
content: if you have any idea what i've gone through just to get it, you'll grab the $40 water based MG small bottle from digikey US today... i got one (841WB-150ML) and taxed 100%. initially i was looking for non water based coating since i guess they will stick better, but they are heavy poison grade (thanks to californication) there is no way they can get imported to me... blockage will be on both sending and destination countries, i was very close to get it from a lady individual person in australia but luck is not on my side. the normal bottle size for industry is like $300 and more... ymmv.

author: Fraser
author_rank: Super Contributor
timestamp: September 30, 2020, 10:42:30 am
content: Just to add to the “Graphit 33” recommendations. I use it to re-coat the mica Windows of end sensitive Geiger Muller tubes. It works superbly as that is what was originally used. I bought mine from Farnell UK. I just checked Newark USA and sadly they do not appear to carry that product. I was not aware that spray graphite was prohibited in the USA so hopefully someone can supply it ? There is also spray copper paint that is conductive but I have not used it myself.

author: Fraser
author_rank: Super Contributor
timestamp: September 30, 2020, 10:53:01 am
content: Hmmmmm, interesting, it certainly appears that graphite spray can paint is not common in the USAI note that non spray versions are available so presumably the issue is with the aerosol propellants ?Time to invest in a small Modelling compressor and cheap airbrush maybe ? Spray the graphite paint using the airbrush after adding a thinning agent. My modelling compressor was around £50 for a decent unit and is great for blowing out equipment fans, PCB’s etc so always useful to have around.https://ph.parker.com/us/en/emi-shielding-paints?cm_mmc=Google%20PPC-_-SLG_CHO-_-ppc%20campaign-_-parker%20chomerics&gclid=CjwKCAjw2dD7BRASEiwAWCtCb7LHSxgMH01DqNEU1ikGzi4ir6V4VQ_YNvkmNt4XpTBHPEdaATxzABoCWAkQAvD_BwEFraser

author: madires
author_rank: Super Contributor
timestamp: September 30, 2020, 11:25:29 am
content: Quote from: Fraser on September 30, 2020, 10:53:01 amThat's strange! Graphit 33 is simply an acrylic resin paint with graphite powder. Nothing special, just like any other lacquer spray.PS: Your compressor is cute.

author: Siwastaja
author_rank: Super Contributor
timestamp: September 30, 2020, 02:36:27 pm
content: Quote from: amspire on September 29, 2020, 10:27:13 pmI wouldn't think so, having measured a few different.Are you sure you aren't measuring it while still wet/moist? They are water-based and seem a bit "conductive" for many hours until the solvent (water) completely evaporates.You can mix fine graphite powder in acrylic paint/ink however, this is what I have successfully tried for through hole activation before electroplating. It needs to be very fine powder, though.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 30, 2020, 04:36:06 pm
content: I don't know about spray cans since they might be difficult to ship due to regulations about hazardous materials.If you don't really need a spray can, you can buy conductive graphite paint in small bottles.Apparently musicians use it to shield the inside of guitars and bass guitars etc to reduce hum.https://www.ebay.ca/itm/Military-Grade-Conductive-Shielding-Paint-for-Strat-Tele-Style-Guitar-Bass/303498722926?hash=item46a9eefe6e:g:jO8AAOSw8q9eVTWAI use it to repair keyboard membranes on my 8 bit junk.

author: Gregg
author_rank: Super Contributor
timestamp: September 30, 2020, 06:11:27 pm
content: Dry graphite in a spray can should be readily available. Tryhttps://www.amazon.com/CRC-Graphite-Lube-Aerosol-Black/dp/B007I9XUD0/ref=pd_lpo_263_t_0/147-5277979-5868239an d as always, Amazon will show a multitude of related and mostly unrelated items.Here is more information on graphite suitable for coating:https://streettechmag.com/2015/06/18/ten-shades-of-gray-ten-uses-for-spray-graphite-lubrication-and-how-it-works/

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: September 30, 2020, 07:07:36 pm
content: Slip Plate is a temporary bond and will not adhere permanently.The eBay guy has to show the same 5 pictures of a bottle of "military grade" goo. Not at all inspiring confidence. Besides it's a brush on where it wastes the product.Still no sources in the US of what can be found in the EUquite readily.But keep the suggestions coming.I found out the "gitar" guys' secret formula. Carbon Black in suspension......in water.I guess I have to find out what the conductivity of Kingsford charcoal briquettes are.Grind them up, and dump it in some water and a binder such as corn starch, and spray it with my gun.I don't barbecue, anybody have a charcoal lump they would like to put an ohm meter to?

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: September 30, 2020, 10:12:28 pm
content: Fair enough, you do need more than water... Attached is my stuff.https://www.ebay.ca/itm/CONDUCTIVE-GRAPHITE-SHIELD-SHIELDING-PAINT-REDUCES-GUITAR-HUM-BUZZ/171335822312?hash=item27e4692be8:g:PNQAAOxykUZTexs~I'd look into little airbrush kit with the canned air and see if that would work. IDK...

author: madires
author_rank: Super Contributor
timestamp: October 01, 2020, 09:20:56 am
content: ... or get a can of clear acrylic lacquer and some graphite powder (for example: graphite lubricant). Mix the graphite into the lacquer and be happy.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: October 01, 2020, 05:42:34 pm
content: Ahhh lacquer.... That's a whole nother can that needs not opening. You see it's still quite humid here and..... anyone who knows what happens in humidity and lacquer. This fall will make my third attempt when the weather calms down to spray a cabinet. This time for sure. I've had plenty of time to sand it again...Quote from: madires onYesterdayat 18:20:56

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: October 03, 2020, 01:44:33 pm
content: I have a busy and have a messy workbench. When I finished a very large footprint repair item it was time for cleanup as I do after every project completion.That's when I discovered my 2" wide roll of copper tape I ordered some time ago.I was going to use it to build shielded capacitors as required to replace the original German types in may of the repairs that I do.Not suitable for what I was asking about earlier, but I forgot about my FY6900 and the garbage that the SMPS spews forth even in the standby mode.I have to hit the main power switch just to listen to the AM BC and SW bands because it is so noisy.So I opened it up and did the following:

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: October 03, 2020, 01:51:40 pm
content: The garbage level went down to almost an imperceptible level.I use the unit to do RF alignments and the level had to be turned up to 2V just to perform the alignment.I bonded the individual pieces of tape with solder blobs and bond wires.Be careful not to let the copper tape get too high on the plastic mount pieces.Burnish all the tape down.Don't let it creep up on the mounting posts.Do cut short ALL PC board leads to keep anything from shorting out.If I had the magic woo shield spray that costs so much, I could have done a better job, but this method works just fine.I'll put a fan in it as soon as I find my 12+ full box of new fans that is somewhere...I don't know where. All hiding since the move a few years ago.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 03, 2020, 02:13:57 pm
content: The good thing about copper foil is a pretty good shelf life, maybe decades. The conductive paint eventually dries out.

author: Quarlo Klobrigney
author_rank: Super Contributor
timestamp: October 03, 2020, 02:24:56 pm
content: It'll probably hold up longer than the Feeltech!

author: amspire
author_rank: Super Contributor
timestamp: October 04, 2020, 10:46:29 am
content: Quote from: Siwastaja on September 30, 2020, 02:36:27 pmI had dried my test patch in an oven, so it was pretty dry. Just tested it 4 days later and it has gone down from 8K to 6.6K.Sure you are not thinking of acrylic paint? People use black acrylic ink for making DIY plated through holes on PCBs.

author: Siwastaja
author_rank: Super Contributor
timestamp: October 04, 2020, 11:35:44 am
content: Quote from: amspire on October 04, 2020, 10:46:29 amWell, obviously it depends on if the pigment used is conductive or not. I would expect carbon black to be conductive. If the label doesn't say, then it needs to be tested.I did the hole activation for through-hole plating first using my own mixture of conductive ink, then moved to the conductive ink by Think&Tinker Ltd,https://www.thinktink.com/stack/volumes/voli/store/inksup.htm, which worked better, finally achieving an acceptable yield (typically no defective or iffy vias in a PCB of about 200 vias). This is freaking expensive, though.

author: amspire
author_rank: Super Contributor
timestamp: October 04, 2020, 12:07:32 pm
content: Quote from: Siwastaja on October 04, 2020, 11:35:44 amThis the brand I am using. Colour is No 028 Black.https://www.daler-rowney.com/fw-acrylic-ink/The instructions say to shake it which I didn't do, so I probably could have got a lower resistance.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: October 05, 2020, 07:05:05 am
content: Quote from: Quarlo Klobrigney on October 03, 2020, 02:24:56 pmLOL certainly longer than mine. I got the Feeltech function generator, it worked for about a week, then it died!