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• So Many Empty Containers

  technoplastique • 06/17/2022 at 15:46 • 0 comments

  One of the challenges with this project is how many empty plastic paint cans (or other containers) it generates. They are very sturdy and well sealed containers, so there's a lot that can be done with them. I've found a few solutions so far:

  - The brand I'm working with now is made of #5 plastic, which is polypropylene. Because I'm rinsing them out, I'm making them clean enough to recycle, and that kind of plastic is accepted for recycling in my city and many other places. That said, I know that recycling still has limits and whenever possible, reuse is a better option.
  

  
  - When making acrylics or oils I could just use them as containers for the new paint.
  

  - I'm using them to store all the components of the paint I'm making now. The gum arabic/honey/glycerin mixture is all suspended in water and needs to be stored sealed. Empty cans are great for this. I'm also using them for dried pigment while I accumulate it before making a batch of paint.

  - Polypropylene can be made into printer filament, and could potentially be made into paint pans for watercolors. The downside to this is that my containers are black, and white pans are preferred to show the color more clearly.

  - Metal cans are much easier to recycle in many areas, so for systems that use metal cans they could simply be taken to a metal collection facility.
  

  - Clean empty containers could just be listed on craigslist or facebook marketplace for others to collect and use!
  

• Dehydrated Pigments and Milling Machines

  technoplastique • 06/11/2022 at 21:59 • 0 comments

  All of the paint store pigments I know about at this point are blended into some kind of liquid, most often water, though that’s not the case for pigments used in oil based paint tinting. For now I’m focusing only on pigments for water based paint tinting (latex, acrylic, etc.).
  
  

  My current process is to dehydrate the pigment, and then rehydrate it. There are a few reasons:

  - Dehydrated pigment takes up so much less space. The space needed to store nearly empty quarts adds up quickly. For efficiency I like to accumulate quite a few of a given pigment before mixing it with binder, and I'm still in my prototyping phase. The neighborhood hardware store I’m working with easily generates 10-20 “empties” per week. My metro area of about 170,000 people has 8 stores that I could be collecting from, most of which are bigger. If I was seriously making paint I could be picking up hundreds of empty quarts/containers a week (hopefully with the help of a like-minded team.)
  

  - If I’m dehydrating, I can rinse the cans out onto my sheet, instead of meticulously hand scraping. This is a huge time saver, and eliminates a really tedious task.

  - It’s easier to create reproducible recipes with dry pigment. Working with weights instead of volumes is significantly easier and more accurate. It also opens up the potential for blending pigments to create other colors.

  - If I want to use pigments to make oils or encaustics I’ll need them to be nearly moisture free.

  - When making watercolor pans, the usual process is to fill part of the way, let it dry, fill more, let dry, and so on. Most watercolor pans have 3-5 layers in them. Adding binder that’s dispersed in water to pigment that’s dispersed in water makes a paint with really high moisture content. This would result in either lots of fill layers, and/or really long dry times.

  - Dry pigment is much more resistant to mold when being stored. For short term work mold isn’t a big concern, but if you allow hydrated pigment to sit for a while before processing it would become a concern.

  I received a very helpful comment from pmaitrot saying, among other things, that the three roll mill is overkill for pre-dispersed pigments. I totally see where they're coming from. My choice to go with this option has a few layers.

  First, I've tried to hand process dried pigment with hydrated watercolor binder, and I was able to do it but it was *work*. It took a while and a lot of physical effort to get to a paint I really wanted to use. They recommend trying a dissolver disc, and that's something I will be experimenting with.

  They also suggest looking for a used milling machine. In Germany they found a used one for about 50€ which is fantastic, but in my searches I'm rarely able to find one in the US for less than $1000, the cheapest on eBay right now is $929. And even if I was able to score a cheap machine, that still doesn't address my intention to make this into an easily reproducible system. There's a huge amount of pigment being thrown away every day, and there's probably an even larger amount of underfunded arts programs that could benefit from this. Lots of localized processing means less wasted time and transport, and more community ownership.

  The other reason I'm thinking of going all in with a milling machine is a really about human nature. Sure, people will start with my instructions and recycling prepared pigment. But then someone will think how holographic glitter or iridescent resin pigment dust would make a really cool paint. Someone else will have some dried turmeric that's such a pretty color, and could that be paint? A dissolving disc probably wouldn't be enough to get all of those things made into paint.

  And finally, a machine built by the owner is also maintainable by the owner. If something goes wrong, they aren't trying to figure out how to repair or replace an obscure piece of lab equipment, they can just go buy a new dc motor to swap out with the bad one.

  At this point...

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• Sourcing Components for The Milling Machine

  technoplastique • 06/11/2022 at 05:50 • 0 comments

  While a three roll mill is a fairly straightforward concept, to function well they have to made to pretty specific technical specifications.

  Each roller turns in the opposite direction of the one before it, and at variable speeds.

  The gaps between the rollers must be very small - almost touching, and adjustable. Ideally the material is run through the mill, then the roller gaps are tightened, and the material is run again, as many as 5 times.

  For most mills the gap between the rollers helps to break down the pigment into smaller pieces. In this case the pigments are already milled small enough that this won’t be a major concern. We’re primarily turning a chunky and inconsistent mix into a smooth and consistent one.
  

  I’ve added for myself the challenge of trying to build this on the lowest reasonable budget. My first prototype will be built using a raspberry pi pico, a motor shield, power supply, and dc motors. A pico seems capable of controlling 4 motors, and this will only require three. This leaves a motor slot left over for controlling the gap adjustment. I have a variety of ideas on how to do that, but they will require testing. I’m sure that will evolve over a number of attempts.

  The biggest sourcing concern for me is to find stainless steel rollers that are readily available for anyone building a milling machine, mountable for precise turning and adjustment, and not impossibly expensive. I have two options I’m considering at the moment. The first is steel rolling pins (the kind for cooking). They’re readily available, but may be difficult to mount without drilling additional holes. The second is stainless steel pipe couplings. The advantage to couplings is that they are threaded on the inside in standard pipe thread, allowing for a variety of ways to mount them. The disadvantage is that they are most commonly available 1-2” long, which is too short for my needs.

  So for now my first move is to get a functional prototype working, so that I have something to build on and improve.

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