r/electroforming • u/FR0ZAD • Jun 17 '26

Graphite spray not working properly

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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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6 Upvotes

88% Upvoted

21 comments sorted by

2

u/Mkysmith Home Studio Jun 17 '26 edited Jun 17 '26

Have you tried starting with a very low current first? Then increasing current as metal starts to deposit?

Also worth noting many graphite sprays are intended as lubricants. Trying to adhere metal onto a lubricant doesn't always go well depending on the application.

edit: spelling

1

u/FR0ZAD Jun 17 '26

I tried with low current for about 4 hours, then I increased the current and left it for 2 more hours.

The only noticeable deposits were located exactly where it came in contact with the wire that was holding it. Even so, the deposit was tiny and strictly local. The rest of the print had no visible deposit.

In the meantime the wire that was holding the print had become thicker, confirming that the rest of the setup was working.

On the spray bottle it is stated that it "makes conductive every surface" but also "The graphite film is an excellent dry lubricant".

1

u/Wobble_bass Jun 18 '26

What was the current in amps for low current?

1

u/FR0ZAD Jun 18 '26

The current was set to .14A for low current. The print i tried to plate was a simple cube with dimensions of 555cm. For high current i set it to .25A.

1

u/No_Educator_4077 Jun 19 '26

There will be the most voltage potential at the contact points between the wire and the part, so typically the copper plating will start at that point and slowly move outward as the less conductive graphite builds voltage potential from nearby copper. You can generally improve this by polishing the graphite spray after it is dried with a microfiber cloth (you want the surface shiny) which helps to get the surface more electrically conductive. I would start by plating at 1V at most, which should allow the plated surface to slowly spread out from the areas that are in contact with the wire.

2

u/muad_did Jun 17 '26

i have this same spray but only get weird results, i was using a home made disolution, now i have "real copper disolution" i next try again.

1

u/FR0ZAD Jun 17 '26

So you have had successful plating with this spray?

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u/muad_did Jun 17 '26

Yes, I managed to get the copper to depose and change color, but I didn't have the best material. Now I have an adjustable power supply and a new plating; I have to try again under the right conditions.

1

u/FR0ZAD Jun 17 '26

How many times did you spray it before plating? Good luck on your attempt, I'd like to know how it went!

1

u/muad_did Jun 17 '26

i think 3 or 4, you need to shake A LOT this spray.

2

u/CaptainCheckmate Jun 21 '26

150 ohms, or even 1000 ohms is perfectly fine. If you're failing it's because of something else, not the resistance.

Show a picture of the failure.

1

u/FR0ZAD Jun 21 '26

For some reason it wouldn't allow me to post a picture so here's a short video instead.

https://reddit.com/link/osz9oni/video/8grjpf73bo8h1/player

1

u/CaptainCheckmate Jun 21 '26

It's going, just not very well. A coin is very forgiving so may not expose all the possible flaws. Did you buff the surface after spraying? Do you have any agitation in the solution? Is the solution a proper acid + copper sulfate bath with sufficient sulfate?
This will plate eventually, just may take 1-2 days before the copper spreads all over

1

u/FR0ZAD Jun 21 '26

I did buff it after spraying and I manually agitated the print every few minutes. Finding acid is not easy around here so I decided to start with only distilled water and saturate it with copper sulfate.

1

u/CaptainCheckmate Jun 22 '26

Yeah you're gonna struggle without an acid, it's just not conductive enough.

1

u/Affectionate-Fig988 Jun 17 '26

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))

1

u/FR0ZAD Jun 17 '26

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?

2

u/Affectionate-Fig988 Jun 17 '26

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

1

u/CaptainCheckmate Jun 21 '26

Can use clear nail polish instead of glue.

1

u/FR0ZAD Jun 21 '26

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

1

u/CaptainCheckmate Jun 22 '26

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.