Mold making and casting has been a huge part of my life for years. It started in the SFX industry, making molds and cleaning up parts for robotic snakes on Snakes on a Plane (really), and has become an even more significant factor with the recent soft robotics project. However, one thing has plagued me this whole time: buckets.
There are lots of elegant methods for prepping a mold, squaring away your shop space, keeping everything all clean and science-y, but no matter how you slice things (unless you’re dealing with 50 gallon drums), pouring out gooey slimy liquid rubber always ends up being a mess. I often end up going through several sets of stirring sticks and dipping disposable cups into my material in the hopes of keeping everything quarantined and safe from contamination. Still I end up feeling like a Dickensian orphan, dipping a ladle into what amounts to $200 of runny goo.
I believe we can do better, and that we have done better. When it comes to sticky viscous consumer products like detergent, syrup, honey, and jelly, the packaging changes to reflect the consistency of the product and the way it’s applied. We’ve got pour spouts to aim detergent into a cup, and a lip/lid interface designed to steer any stray film of fluid back into the bottle. With sheer thinning colloids like ketchup, there are squeeze bottles with shut-off valves molded into their lids.
When it comes to silicone, urethane, or any 2-part RTV liquid casting rubber, the container should also fit the product. When you pour directly from a bucket, you end up with a huge wave front of rubber, sliding down the side of the container, with no way to coalesce it into a small controlled stream. You end up needing one set of hands to hold the bucket, and another to use a stirring stick to guide the flow. It’s equally problematic dipping a cup into the liquid. The cup will hold on to a lot of liquid even if you thoroughly scrape it off. It also offers you the wonderful opportunity to contaminate the entire pot and seize up an entire batch of expensive specialty rubber. There’s also the nature of viscous fluids, which is to form small trailing threads that develop plans and ambitions of their own.
There are a couple of wrinkles that Smooth-On and other manufacturers have to take into account. I can understand why the nonreactive semi-rigid plastic buckets are so universal. They want to keep the packaging as consistent as possible, so as not to spend a fortune on tooling. They’d like to have things be reliable, so they don’t risk having an innovative and expensive new container drastically shorten the shelf life of their product. They want something that fits a huge range of their products and, since so many materials need to be mixed before pouring, they want something with a lot of workspace to get in and dig around with a spatula.
These are all healthy goals, but it misses out on what I consider to be 90% of your interaction with the product as a consumer: messing about with stupid sticky buckets. So, I’m anal. I’ll often set up a work space with drop cloths, prep all my tools, use only disposable mixing equipment, and wipe everything down after use. If I don’t retain this level of anality, things quickly spiral into syrupy madness.
I think I’ve come up with a solution. It’s based off of Victorian mustache protecting ceramic cups, and integrates some of the drip reducing angles from detergent spouts. It still allows people to dip and mix and pour things back into the bucket as well. I believe it can be injection molded simply, and just attached to existing buckets with a heat sealer, requiring no significant change in how stuff gets packaged, filled, or labeled. If you want, you can view it in 3d on i.materialise.
Top photo credit: Herbert Art Museum, Coventry.