Instructables
Picture of Conductive Paint
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The goal of this experiment was to try to find an alternative to commercially available conductive paint. It is incredible stuff but expensive. I've read other Instructables like Makerboat's $1 Conductive Ink and IceCats' Paper Electronics. They helped me arrive at my own recipe, which uses only two ingredients but I think my testing is more reliable.

To make the winning recipe you need:

  • Graphite powder*
  • Acrylic paint
  • A jar with an airtight seal

To complete every test you need:

  • Elmer's Glue-All
  • Titebond III Wood Glue
  • Acrylic paint
  • Wire Glue (tm)
  • Graphite powder
  • 4 wooden toothpicks
  • 4 jars with airtight seals
  • Paper
  • Ohmmeter
  • 2 zip ties

*Be careful with graphite powder because inhalation can lead to respiratory problems.

 
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Step 1: Glue-All and Graphite Sample

Picture of Glue-All and Graphite Sample
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For the first recipe graphite powder was mixed with Elmer's Glue-All until the consistency was spreadable. Be careful when adding the glue because squeezing the bottle will shoot a blast of air into the jar and graphite powder will blow everywhere. The third picture illustrates this.

The ratio was:

  • 2 parts Elmer's Glue-All
  • 1 part graphite powder

The result was fluid but very thick. It could still be used as an adhesive.

Two lines were drawn with the toothpick. One thin line and one thick line. The toothpick was wiped off on the side of the jar and allowed to dry next to the lines.

Step 2: Titebond III and Graphite Sample

Picture of Titebond III and Graphite Sample
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The second recipe was Titebond III and graphite powder.

The ratio was :

  • 1 part Titebond III
  • 1 part graphite powder

The result was fluid but not runny.

Two lines were drawn with the toothpick. One thin line and one thick line. The toothpick was wiped off on the side of the jar and allowed to dry next to the lines.

Step 3: Acrylic Paint and Graphite Sample

Picture of Acrylic Paint and Graphite Sample
2014-07-20 21.31.17.jpg

The third recipe was acrylic paint and graphite powder.

The ratio was:

  • 1 part acrylic paint
  • 1 part graphite powder

The result was slightly thicker than paint.

Two lines were drawn with the toothpick. One thin line and one thick line. The toothpick was wiped off on the side of the jar and allowed to dry next to the lines.

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M4n0v3y made it!yesterday

It really works! I used acrylic resin and that glue that shoemakers uses to fix shoes ( I don't know the name of this in English... Glue for footwear). My formula allows to apply a post process of electrolysis for deploy a fine layer of copper over the circuit.

Cola_condutiva-Realce-0004.jpgCola_condutiva-Realce-0001.jpg
24Eng (author)  M4n0v3y22 hours ago

That's awesome!
What kind of consistency does it have? What proportions did you use?
A lot of people will be grateful to see your work.

M4n0v3y 24Eng18 hours ago
Hello!

I am about to publish a flat cable and a flexible circuit project based in this conductive paint. In this publish I will describe the detailed process to produce the tint.

It will be published very soon!
24Eng (author)  M4n0v3y17 hours ago

Awesome. I'm so pleased this could help you make your own project. Be sure to post a link here and you might even be able to put it in the Remix Contest.

lazemaple29 days ago

so can this conductive paint be used for electroforming or electroplating?

Now a person must now just get the formula consistent and then make your own resistors and circuits now how will I be able to solder this!!

24Eng (author)  KROKKENOSTER1 month ago

Agreed. Consistency wasn't the focus here and when my results were clearly in favor of one ingredient it didn't seem important. Now the key will be to fine tune the ingredient proportions like you said to get reliable and predictable results. Soldering isn't necessary, you simply apply the paint over your leads and it holds it like glue.
Metal powder has been discussed a few times in previous comments and I agree, metal is definitely a superior conductor but more dangerous to work with because it can ignite explosively. Aluminum has been shown to do that anyhow. Graphite powder is also available at many hardware stores so it's easy for anyone reading to get a hold of. I like the way you think!

o4orsum1 month ago
Nice to see such a methodical approach
24Eng (author)  o4orsum1 month ago

Thank you. High school science class is where it all started. That was two decades ago!

If a person can get METAL dust like lead aluminium copper etcetera as the conductor and make this substance so that it is JUST workable and then add a volatile liquid like alcohol laquer thinners or the like and then make your conductor like that. I am just speculating as my knowledge of this is not that hot but they will be better conductors than carbon

thinkpadt301 month ago

Very nice and easy-to-follow 'ible that was nicely laid out like a science experiment. It sure made experimenting with conductive paint a real possibility, and inexpensive, too. For some reason, Instructibles would not allow me to reply to the comment about using aluminum powder. When I was in high school, I used a mixture of aluminum powder and sulfur powder to power a rocket I constructed. It was a pretty powerful propellant. 4 oz of the mixture electrically ignited with 6 volts propelled a 10 oz rocket about 50 yards from about a 30 degree ramp, so I definitely would recommend that if you must try aluminum powder, to use caution, especially working with electricity. Even a shorted AAA battery can generate a fairly intense heat, far more than is needed to ignite the correct mixture of aluminum and sulfur. Sulfur is an ingredient in many common products, and you never know if it can be leached to combine with the aluminum. Just sayin'.

24Eng (author)  thinkpadt301 month ago

I have appreciated how many people with chemistry knowledge have come to this experiment. Chemistry is not my strong suit and more thoughts are always appreciated. It's also great how you are able to relate your experience in rocketry into conductive paint. Thank you for your words of caution as well.

thickmike1 month ago

I used to be a paint chemist. We found that conductivity depends on the fineness of the black pigment and the degree of dispersion. There are special fine pigments used e.g. Ketjen Black (https://www.akzonobel.com/polymeradditives/our_products/superconductive_carbon_blacks/) they have a very high surface area per gramme. Also grinding the pigment will give better results. High shear and wetting agents(surfactants) are needed to wet the pigment out (think more of a pestle and mortar rather than a cocktail stick in a pot). Viscosity can be reduced by adding water to water based paints or a suitable solvent.

G'night.

I was thinking in reduce viscosity - in the case of acrylic paint - some 5% or 10% of acetone.

First find out if your acrylic is water based or solvent based. If it is water based it should say to wash brushes with water after use...in that case reduce viscosity with water.

If your paint is solvent based then read the cleaning instructions and you can use the solvent recommended for brush cleaning.

Acetone is extremely volatile and you might find that it dries too quickly when you apply the paint, but if it's all you have you can give it a go.
24Eng (author)  thickmike1 month ago

Do you think that if the better carbon additive were used the sample would retain its conductivity after being submerged? This formula seems to work fine and dandy when there is nothing acting on the paint but as soon as it's flexed or submerged it all goes pear-shaped. Being able to use more a resilient medium in conjunction could lead to a very useful paint.

I'm glad you came by this page.

thickmike 24Eng1 month ago
Most of the mechanical and chemical properties of the paint will come from the binder (in your case the paint or glue you put the powder into). The main advantage of the special pigment is that it is conductive at much lower loadings (you don't have to put so much stuff in to get the same effect, or you get a lower resistance at the same loading). I guess the first step would be to find a paint that works under the conditions you need, then try the graphite in that paint.

Flexibility is perfectly possible (we were using the paint on polypropylene/EPDM copolymer). Why do you need it to be submerged? Won't that short any circuit you make?
24Eng (author)  thickmike1 month ago

People have asked about the feasibility of using this for electroforming and electroplating. Current solutions are expensive. Maybe you can shed some light on that. Electroplating and electroforming require a very low viscosity paint so that details are not lost. Do you have any ideas that would be watery and waterproof when dry?

thickmike 24Eng1 month ago

in my experience thin films of conductive paint tend to have high resistance (resistance being inversely proportional to film thickness). We were painting films around 10 microns thick and getting a point to point resistance over 5cm of around 20MOhms. This was fine for our application, but sounds very high for things like electroforming and circuits.

Problems you run into are to do with viscosity of the wet paint. To reduce the resistance you need more pigment in the dry film. Higher pigment loa dings increase the viscosity of the paint massively, so you have to add lots of solvent or water depending on your paint type. This makes your paint very low solids content which means it is very hard to get a thick enough film in one coat. Multiple coats would be needed which makes your process slow and less reliable.

For some of the applications discussed here (eg printing circuit boards) I think it will be very difficult to get that balance between resistance, viscosity and solid content.

24Eng (author)  thickmike1 month ago

Thank you for all the great information. Now I see why the commercial coating is expensive. In retrospect I wish I had performed resistivity tests over time as the samples soaked. It's possible they might retain their conductivity long enough to be useful. I've never done electroplating or electroforming so I can't say.

thickmike 24Eng1 month ago

there are resins that are water based, but dry to give a water resistant finish (I wouldn't say waterproof as such). Some of them are crosslinkable 2k coatings that require a hardener to be added just prior to painting. Be careful if you start experimenting with these resins as some of them are dangerous (eg isocyanate curing resins). If I was looking in a DIY store for something suitable (rather than from commercial industrial chemical suppliers like Bayer) I would check out the floor coatings. I know there are plenty of water based coatings for floors that are very water resistant.

M4n0v3y1 month ago

Hei Brian.

About that silicon-graphite mix for conductive purpose, may that works too?

I tried use silicon plus graphite for this purpose in a near past, it doesn't works. Maybe the proportion or the grain of my graphite powder...

24Eng (author)  M4n0v3y1 month ago

I got absolutely no conductivity from my silicone-graphite mix. I held the probes right next to one another and my meter wouldn't register anything. I don't think you did anything wrong, I think it's just the insulation properties of silicone caulk.

M4n0v3y 24Eng1 month ago

Yeap... I agree.

But with a few conductive lanes in a acrylic layer in the core of a silicon sandwich I may have a flat cable... what you think?

( don't need to response... just think about...)

I will post my results very soon!

Txs, regards!

M4n0v3y1 month ago

Hei!

In the table that you presented I see acrylic paint thin line and thick best results than Wire Glue, is that rigth? Okay! ( 60 ohms per inch in a thick line is less than Wire Glue! Good for a flat cable maybe...)

So, I was wandering If we use aluminium powder instead graphite or kind of a blend (40% graphite, 60% aluminium) 60% and acrylic paint 40%.

I am about to make my experiments and I will let you know!

Thank you!

24Eng (author)  M4n0v3y1 month ago

Yes, the paint-graphite sample tested better than Wire Glue(tm). I suspect this is partially due to the high viscosity of the paint-graphite because the sample was thicker.

Someone has reported good luck with Al powder so I hope you can confirm his results. Your results would make a great addition to the community project this has become. Let us know what you find and how you found it.

M4n0v3y 24Eng1 month ago

G'nigth!

I am about to order the raw material for do my essay. As I reach the results I will go to publish here ( a note in this article and a publish in the site - I think will need a help in English language...LOL).

So, wish me luck!

24Eng (author)  M4n0v3y1 month ago

Good luck with your essay and your results!

nevtxjustin1 month ago

I use graphite paint that is conductive.

http://www.vansicklepaint.com/ezslide/

http://www.tractorsupply.com/en/store/ez-slide-gra...

There is a warning on the container that it is electrically conductive.

EZ-Slide Graphite Coatings can be used on farm and
industrial equipment, gravity boxes, corn picker heads, combines, truck
and wagon beds, buckets, blades, garage door tracks, snow blowers, lawn
and garden tools, saw blades, dump bins, solar panel coating, snow plow
blades, and more! EZ-Slide can also be used under lawn mower decks.
EZ-Slide will create a smooth surface that will prevent lawn discharge
from sticking to the underneath of your mower deck.

Trike Lover1 month ago

I like this version. I have experimented with the charcoal version from another Instructable, Makerbot's "$1 DIY Conductive Ink..." I've also experimented with using a small amount of fine aluminum powder (had it in a jar in the workshop - been there for at least 40 years, LOL). It worked quite well, but the optimum ratio (and please bear in mind I did not do systematic testing as you did) seemed to be about 2/3 Al powder to 1/3 acrylic paint by volume. I suspect this is because the particles in my sample were very small, and must touch in order to conduct. I also added a drop of clear "crafter's glue". My intended use is to line the control cavities and pickup rout cavities on my electric guitars. Commercial conductive paint is available, but the price is ridiculous.
I had a small jar of powdered graphite, again something that has been sitting there for ages - about 2 oz by volume. However, when I started checking around to find powdered graphite in quantity, I was appalled at the prices here in Western Canada. On various U.S. sites, I found 16 oz (by weight) jars priced from $14 to $28. However, none would ship to Canada. Here, I found similar prices but for 5-6 gram tubes, designed for squirting into locks. I am sure that powdered graphite must be available in bulk somewhere, but I've yet to find it.

Aluminum powder was commonly available at paint stores when I was 12-14 years old - I remember purchasing a jar to mix with some type of paint, in order to paint the cowl of my soapbox derby racer silver. Worked really well, too. Now, powdered Al seems to be much more difficult to find. It is possible to make your own using a re-purposed food grinder and then a rock tumbler or ball mill, but the process is lengthy. I suspect the same would be true for making copper powder from copper metal pieces, such as copper water line, etc.

I would be really interested to know if anyone has found sources in Canada for either powdered graphite, aluminum powder, or copper powder in quantity (say 16 oz jars) for a reasonable price. I have heard that artists' supply stores sell graphite in bulk, but have yet to actually find any. Even if it came in block form, grinding it to powder should be do-able with a small amount of wetting agent in the blender.

This was a great writeup, and your systematic results were very helpful. I've mixed up all of my remaining graphite powder with acrylic paint, so I have enough to do one guitar, anyhow.

DasBigfoot1 month ago

I like this... Thank You!

I didn't take the time to read all of your discussions, but... In regards to increasing the conductivity of the glue mixture, you might consider adding a fine aluminum dust to the mixture. You could do the same with copper, which is more conductive than aluminum. You could use a chop saw, although that would produce pieces as large as 1/8" (too large to use with this mixture). Maybe some kind of grinding wheel that wouldn't clog up? You would still need to use the graphite. Try experimenting with other glues, checking for their R value. Possibly a silicone or acrylic caulk? Let me know what you come up with.

24Eng (author)  dwilliamson11 month ago

My Dremel has fiber cut-off wheels that would make short work of copper wire for use as copper dust. Aluminum powder scares me due to its explosive nature. I'm sure it would be fine once mixed and for all I know copper powder is just as bad. I have tried silicone as a medium and that creates a wonderful insulation despite mixing with copious amounts of graphite. Which is good to know but not useful as a conductive paint which is disappointing because the flexible properties of the silicone would be really nice.

Copper powder and graphite suspended in an acrylic medium would probably look really neat!

Arandall861 month ago
very cool experiment. have you thought of any applications for it? all I can think of is low voltage "wireless" stuff.
24Eng (author)  Arandall861 month ago

The application I had in mind was for my roommate who is a print artist. She wanted to position white LEDs inside of a picture frame to light her prints in very specific ways. She asked if there was a way to finely position LEDs and I started running through ideas involving breadboards, header pins, solid core wire, and twin brass rails. Then I thought of the Wire Glue(tm), which she got me in the first place, and I ran with the idea of making my own. As I mentioned the Wire Glue(tm) is worthless as glue and more like ink. My idea is to take her finished print, carefully trace two lines of conductive paint around the outside of her print and allow her to place the LEDs as she likes then hold the LEDs in place using some more paint.

What do you have in mind with "wireless" stuff?

For your picture frame, I think you may have a problem with the high
resistance of long lines of conductive paint. Under normal conditions
an LED requires a series resistor to control the current, but careful
measurement of the length, width and thickness of the paint line may
enable you to calculate a suitable value.

(Greater length = greater resistance, greater cross-sectional area = less resistance. http://en.wikipedia.org/wiki/Resistivity#Definiti...

A
possible solution for the picture frame may be two thin lengths of TCW
(tinned copper wire) stretched between nails in concentric rectangles,
then attach SMD LEDs and resistors between the two wires with conductive
glue. (Solder would be stronger but more fiddly.)

24Eng (author)  ElectroFrank1 month ago

Very true. We are clearly thinking alike because the twin brass rails I had in mind were along the same lines as running two copper wires but brass rails would keep themselves straight and as long as I brace them apart I shouldn't have to worry about a short. The most elegant solution may be to bury a thin copper strand under the paint, which would beat ohm's law, and still allow an LED to be stuck in place with the conductive paint.

I'm not sure if my roommate wanted to have the lights attached to the paper or the frame. Putting eight nails into a wooden frame would be the most logical route if that's what she wants to do.

For the current purpose (pun intended), for neatness, for "nails" read "small pins", which if decapitated, could be virtually invisible under a tiny drop of paint. And the wires could be recessed into a groove ruled in with a small spike. Or the LEDs could be mounted on pins put through the board, and the wires connected the other side, to position the lights anywhere in the picture.

Now, a street scene with illuminated car and street lights ? Fireflies ? Flashing fireworks ? Let your mind overflow with possibilities . . .

Pic Frame LEDs.gif
rkrishnan71 month ago

Thank you for a great description. Your efforts at controlled experimentation saves so much time for the rest of tweakers!

I wonder if one can control teh viscosity of teh Acrylic paint by adding some king of thinner - turp, acetone, alcohol or such ?

24Eng (author)  rkrishnan71 month ago

Thank you.

Acrylic paint can be thinned with water. Nothing fancy. If you don't need a thick layer there's no reason you can't dilute the paint a bit.

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