|Monthly Tech-Tip |
Being more independent is now cool again. Actually, it is being forced upon us by necessity because of supply chain issues and skyrocketing prices of convenience glazes, bodies, engobes, etc. Independence involves using sieves. True, it is no problem for a potter or lab tech to manually coax a glaze slurry through a small 80# sieve. But real independence is about sieving in volume - clay bodies and casting slips. About making your own porcelains and sieving out agglomerates. The ultimate in independence: Sieving particulates from your own native clay slurries. And doing it at 100, 140 and even 200 mesh. That requires a sieve shaker. This one cost us less than $100 to make. Of course, a Tyler sieve (or similar) is needed, these can be purchased on Ebay or Amazon. And a vibration motor, some metal and hardware and a friend with metal fabrication tools.
Supply chain issues during Covid made it difficult to get posts. I wondered if I could make my own. I have access to the same ceramic materials that post manufacturers use. Firing to the highest temperature they will ever experience should make them dimensionally stable, for me that is cone 10. In the past it was always a hassle to make the extruder die, but not anymore. An ordinary 3D printed PLA template will easily withstand the pressure in a hand extruder (even if printed with infill). The precision tapering possible is amazing. Notice that the floating centre has a tapered bridge to help clay knit together as it flows around it. What about a refractory plastic body? I started with L4543, it is cheap to make and dries quickly with minimal shrinkage. To cut posts to length with a square end I print sleeves to slide them into. I you would like the 3D drawing it is in the Files manager in Insight-live.com, it is parametric and easy to change.
Material prices are sky rocketing. And, the more complex your supplier's supply chain the more likely they won't be able to deliver. How can you adapt to coming disruption, even turn it into a benefit? Learn to create base recipes for your glazes and even clay bodies. Learn now how to substitute frits and other materials in glazes (get the chemistry of frits you use now so you are ready). Even better: Learn to see your glaze as an oxide formula. Then calculate formula-to-batch to use whatever materials you can get. Learn how to adjust glazes for thermal expansion, temperature, surface, color, etc. And your clay bodies? Develop an organized physical testing regimen now to accumulate data on their properties, learn to understand how each material in the recipe contributes to those properties. Armed with that data you will be able to adjust recipes to adapt to changing supplies.
Material prices were sky rocketing (and still are). Prepared glaze manufacturers have complex international supply chains. Now might be the time to start learning how to weigh out the ingredients to make your own. Armed with good base glazes that fit your clay body (without crazing or shivering) you will be more resilient to supply issues. Add stains, opacifiers and variegators to the bases to make anything you want. That being said, ingredients in those recipes may become unavailable! That underscores a need to go to the next step and "understand" glaze ingredients. And even improve and adjust recipes. It is not rocket science, it is just work accompanied by organized record-keeping and good labeling.
Making your own sieve shaker
All you need is an inexpensive vibration motor from Amazon, a five gallon pail, some metal and welding and 3D-printed collars to hold the sieve in place.
Sieves are important in ceramics for removing particulates and agglomerates from glaze, engobe and body slurries.