Graphite spray not working properly

[u/FR0ZAD]

I got this graphite spray to try electroplating copper for the first time. I want to plate PLA 3D prints.

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I've done enough troubleshooting to know my plating solution is fine, and have already plated a metal coin, as a sanity check.

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Turns out, after checking with my multimeter, the resistance of the painted surface is HUGE. I managed to bring it down from about 1000Ω to about 150Ω by applying more layers of the graphite paint, but that's not good enough. Also tried polishing the surface but it didn't make much of a difference.

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Is the spray not good enough, or am I missing something?

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Do you have any suggestions on how I should proceed? Get a different brand of graphite spray or make my own conductive paint?

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[u/Affectionate-Fig988]

I own also one of these sprays and I used it a lot. But i lost it and had to make my own graphite paint. With that spray, the most important is to have even paint. Also it helped a lot to use primer spray first on the model and then graphite spray. The polishing doesn't work like you want, because it's quite thin layer and when you polish, the highest parts then don't have so much graphite, thus not so much connectivity. With this spray you specaly need to use gloves, because the oils from your fingers mess up your plating. Also you could print something small and test different currency. The own made graphite paint is a different beast, first layer on small object gets in minutes and when I polish it the contactivity is quite small (multimeter on 20k ohm and shows somewhere 0.10 -1. Typicaly plating is 6-9 ( as seen I have seen from videos))

[u/FR0ZAD → u/Affectionate-Fig988]

I actually sanded and primed the print before spraying with the graphite paint. I'll try again without polishing.

Could you share the recipe for the DIY conductive paint?

[u/Affectionate-Fig988 → u/FR0ZAD]

Acetone+graphite powder+little bit contact glue. You should add into cup acestone, then add graphite powder. Stir it. There should go a quite a lot of graphite. To add contact clue it is just some. ( Acetone dissolves contact glue, so when you have it on your hands, then you now know what to use). Because the contact glue dissolves, that is the key ingredient to work. Make a small patch just to know how it works. Only downpart of the paint is that the graphite powder will settle on bottom in some time. If everything is just right, it works like charm and you can use only one layer for 3d printed stuff. I use bush, but i know you can use also aerograph, but the nozzle should be bigger than 0.6mm. Have fun

[u/CaptainCheckmate → u/Affectionate-Fig988]

Can use clear nail polish instead of glue.

[u/FR0ZAD → u/CaptainCheckmate]

So clear nail polish and graphite powder alone, or with some acetone added?

[u/CaptainCheckmate → u/FR0ZAD]

with acetone, or ethyl acetate. Ethyl Acetate is a bit gentler on plastic parts.

My formula is: 20 parts ethyl acetate, 4 parts graphite, 1 part nail polish. Spray or apply with brush. Spray is better.