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Really Non-Settling Pigment: Nanometer Carbon Black


#1

In a previous posting about 1.5 micron molybdenum disulfide, I alluded to some experiments I had done with 30 nanometer grade carbon black I sourced from Graphene Supermarket.

After numerous attempts at methods to control the flocculation of this pigment, I seem to have something that works. As you get really small, the tendency of particles to stick to each other increases, so while the 1.5 micron MoS2 could simply be dumped into resin in powder form, the nanometer scale carbon black needs to be made into a dispersion with chemicals that will help it disperse evenly and prevent it from clumping up.

I used this pigment mixture last week in some clear photocentric3d resin to print a gear bearing, and the resin’s been sitting in my vat ever since. I examined the resin that’s been in the vat for about 9 days just now, and made a video of the result:

There’s pretty much no noticeable settling, which matches the testing I did earlier with a test sample of MJ G+ in a graduated cylinder after 9 days:

I probably put too much glycol ether in the recipe, since small amounts have started to settle out. Perhaps just half as much would have been sufficient.

After sufficient time, the pigment does settle (graduated cylinder sample is showing slight but noticeable settling after 2 months) so it’s not strictly “non” settling. I also think that your results in resin might vary depending on whether you have the ability to sonicate your resin after mixing with pigment. An ultrasonic batch will ensure that pigment is fully deflocculated and gives the dispersants the best chance to keep things dispersed.

Take a look at the video and see how the results compare to what you’ve seen with other types of pigment in the vat after a few days. If you think that the results look good, I may make some sample amounts available through an Etsy store or something to cover shipping and packing materials.


#2

This is interesting, is this still your preferred method of pigmenting resin? Would you mind sharing details of the deflocculation recipe/procedure?


#3

The problem with this formula is that it uses difficult-to-source materials, in particular DISPERSBYK-2025 and SYNGERGIST, both from BYK. It also does not permanently disperse the pigment (it does flocculate on the months timescale, as I noted in the original post).

The lack of permanent stability is annoying, because when nanoscale particles flocculate, they require sonication to break up. On the other hand, molybdenum disulfide just requires hand-mixing and requires no additional dispersants.

I think it really depends on how much you print, if you print enough that you’re consuming resin at a faster rate than it flocculates, then this nanoscale blend might be an advantage in your workflow. However, if you don’t (and I don’t), moly is way easier to deal with in all regards.


#4

Thanks for the reply. I kind of assumed this would be the case. I have some moly on the way, sounds like it will be the best bet.