MG Chemicals 838AR-P Total Ground Carbon Conductive Pen, 4g

I'm very glad this product exists. Saved me hundreds of dollars!The material flows pretty well once you get the hang of it. It's similar to a paint pen, but with nickel in solvent. Let it dry! It wont conduct until the metal settles and the solvent dries. It was fun to use a multimeter and watch the resistance drop as the fluid cured.I used this to repair a laminated keypad ribbon cable in a microwave that somehow got a melty trace. I also used it to repair the damage I did trying to fix the problem before i knew this product existed. It will now and forever be a part of my electronics kit. Perfect for membrane trace repair!Adhesion is good on plastic. The output width is about 2mm. It's a fluid but not super runny, especially after the solvent flashes off. Build up a couple of coats for best conduction.It takes a minute to get used to dispensing the material. The pen uses a plunger valve tip that has to be pushed against the surface before flow will start. You control the flow with how hard the tube is squeezed. Wiping the tip after every lift-up makes things go smoother.

I've been using these to repair the plastic membrane sheets of my IBM and Unicomp Model M mechanical keyboards for several years and have gone through at least three so far. The silver pens are expensive, but I read somewhere that it's best to keep using the same metals throughout, so I buy those.They're not the most intuitive to use, so you should make sure to try it out on a piece of scrap paper or something you're not afraid to ruin to get the hang of it. Always make sure to give it a good shake first (like a paint marker) and squeeze the body while laying the ink down. And if you mess up, even after it dries, it's easy to scrape away with something like a screwdriver or an exacto knife, at least on smooth plastic.My picture is of some traces I repaired on a Model M membrane. I accidentally scraped them off while cleaning away a nasty stain and fixed it using this pen.

Very Nice I would buy again.

Worthless. Regarding carbon conductive ink gets puked on and produces this 2mm thick trace that is far too messy for delicate traces. But that almost doesn’t matter because it doesn’t conduct. There is not in fact any current coming through and most of the time, the multimeter shows infinite resistance. Even after shaking the pen like a maniac, i get at best 190 ohms at 10mm long and 2mm thick trace. The Mylar keyboard membrane I was trying to repair is now ruined.

I was working on a Turbo Express system with non-functional buttons. The capacitor on the controller board had leaked and dissolved the carbon traces for the buttons, so I purchased this carbon ink to see if I could use it for a more 'authentic' repair rather than jumping the traces or replacing the board in its entirety.After practicing drawing a bit on some regular paper, I cleaned the traces thoroughly, took a bit extra off the damaged sections and contact points and carefully applied the carbon ink. Most went on pretty easily (follow the instructions, they are helpful) however there were a couple spots where I flowed a bit too much and had to clean / reapply. Overall, it took maybe 15~20 minutes to read the instructions, practice a bit and perform the repair / get it how I wanted it (this being my first time using conductive ink, so next time it shouldn't take as long). My repair is barely noticeable!Most importantly... I let it dry for 10 minutes and tested everything out, and all buttons worked perfectly!This stuff is a God send. Follow the instructions and it really isn't difficult to properly apply... Make sure you thoroughly clean any surfaces you plan to write on, and remove a bit extra from damaged sections and contact points of existing traces, squeeze the pen firmly but not excessively while applying pressure to the ball point and use deliberate motion...Great product!

If you really need one of these, they will work fine if they haven't expired. It seems the units that come from Amazon might be past their shelf life. Consider alternative sources that will provide in-date units.

Wonderful product

My car's touchscreen was broken, and this made it an easier fix. The screen has a ribbon cable glued to one side it, which connects to copper tracks printed between two panes of glass. The connection between the ribbon cable and the copper tracks on the glass screen had broken. I don't have any experience soldering, but I don't think I could solder onto glass. So I picked up this conductive pen, put four dollops to complete the four connections. Let it dry for about thirty minutes. Then I tested and saw reasonable resistance values. So I put the screen and my car back together, and to everyone's surprise the touch screen was actually working!I will say, the pen smells. I would only use it in a well ventilated place, and leave the area while it's drying. That said, I did use it indoors and didn't die either.It doesn't write smoothly like a ballpoint pen. The lines it makes are maybe a millimeter thick, and I think you would have to go over the lines at least once while still wet to get a smooth, connected line.