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Click the links to the left to get information and pricing on our products. Click the "Plainsman Data Sheets" for details information on the use and Plainsman clay bodies and glazes. The blog below is intended to help you with all manner of technical issues in ceramic hobby production, these posts come every few days, so check back often.
Technical Tips Blog
An original container bag of ceramic rutile
The primary use of this material is obvious: For welding rods. However notice the bag bottom is marked "Ceramic Rutile" (with a batch number). This bag is very small, this material is very dense and heavy. Why would a product intended for making welding rods be useful in ceramics? The answer is very interested.
Context: Ceramic Rutile
Monday 18th October 2021
A frit softens over a wide temperature range
Raw materials often have a specific melting temperature (or they melt quickly over a narrow temperature range). We can use the GLFL test to demonstrate the development of melt fluidity between a frit and a raw material. On the left we see five flows of boron Ferro Frit 3195, across 200 degrees F. Its melting pattern is simple and non-volatile: It starts flowing at 1550F (although it began to turn to a glass at 1500F) and is falling off the bottom of the runway by 1750F. The Gerstley Borate (GB), on the other hand, goes from no melting at 1600F to flowing off the bottom by 1625F! But GB has a complex melting pattern, there is more to its story. Notice the flow at 1625F is not transparent, that is because the Ulexite mineral within GB has melted but its Colemanite has not. Later, at 1700F, the Colemanite melts and the glass becomes transparent.
Sunday 17th October 2021
Frit Melt Fluidity Comparison - 1850F
Fired at 350F/hr to 1800F and held for 15 minutes (I already did firings from 1300F-1800F in 50 degree increments, all of them are visible in the parent project). Frit 3110, 3134, 3195, F75 have all flowed all the way down for many previous temps. LA300 and 3124 were just starting at 1800F, look at them now! 524 and F38 have gone from half-way at 1800F to water-falling over the end. Frit 3249 is still not out-of-the-gate but F69 (the Fusion Frits equivalent) is half-way. Note how the melt surface tension is evident by the way in which the melts spread out or hold together. By contrast, Gerstley Borate, the only raw material here, suddenly melted and flowed right over the cliff between 1600 and1650!
Context: Fusion Frit F-524, Fusion Frit F-69, Fusion Frit F-15, Ferro Frit 3602, Fusion Frit F-75, Fusion Frit F-38, Fusion Frit FZ-16, Ferro Frit 3195, Ferro Frit 3134, Ferro Frit 3124, Frit B325, Frit LA-300, Ferro Frit 3249, Ferro Frit 3110, Frit, Comparing the Melt Fluidity of 16 Frits
Monday 11th October 2021
Get ready for supply interruptions
Material prices are sky rocketing. Prepared glaze manufacturers have complex international supply chains. It is only a matter of time until you are affected. We are happy to sell you bottled glazes, if we can get them! But 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 labelling.
Wednesday 6th October 2021
100 years ago, the Plainsman Clays plant would have been a small outbuilding at ACP
Plainsman Clays is built on the site of the former Alberta Clay Products Co. Ltd. The Plainsman plant is overlaid on the lower part of this 100-year-old photo. ACP was North America's second largest brick manufacturer. The plant and high temperature kilns, were all constructed using bricks and firebricks made in a temporary kiln on the same site (using clay mined nearby). No outside brick was purchased. The plant produced a wide range of brick but was most known for its production of vitrified salt-glazed pipe used in sewer and water lines across the west. During the period when this photo was taken the plant had 325 workers. In 1962 the main building burned to the ground! Shortly after, Plainsman Clays began operation in the small building beside the uppermost kiln. And moved to the current site in 1971.
Thursday 16th September 2021
Are you using your expensive kiln like a pop-up toaster?
Put the pots in, select a cone, press start. It is time to rethink that approach! Seriously. The Bartlett Genesis kiln controller is standard equipment on hobby and production electric kilns now. It is not meant to be run like a toaster! Good glazes are about much more than recipes, they are about firing schedules. None of the built-in "toaster schedules" have hold times on any segments, drop-and-hold sequences or controlled cools. Or even fire-to-cone accuracy. Yet such are a must for defect-free glazes, enhancing the effects of reactive glazes that must develop crystallization or variegation or firing accurately. It is easy to program: Tap the blue edit button to edit a program, tap a column of any segment to edit its value. Tap a segment number to delete or duplicate it. Google "bartlett genesis controller" for videos on creating and editing a schedule.
Context: When the cone does this I need to adjust the program, Manually programming a Bartlett V6-CF hobby kiln controller, Bloating on a range of bodies at cone 6: Why is this happening?, Be thankful for the hobby kiln controllers we have in North America, Bartlett Genesis Kiln Controller Programming, Firing Schedule, Kiln Controller
Thursday 16th September 2021
Three rutile blue glazes at cone 6
These are GA6-C Alberta Slip floating blue, AMACO Potter's Choice PC-20 Blue Rutile, GR6-M Ravenscrag floating blue. The clay is M390. The firing is cone 6, the schedule is C6DHSC (drop-and-hold, slow cool). The inside is GA6-B. The two on the left develop the blue color because of the slow-cool, the one on the right works on fast-cool because it contains cobalt (although it will fire somewhat more mottled). The centre one is a bottled commercial product, it was painted on in three coats. The result is quite compelling, this is a good place to start if you want the rutile-blue effect. Remember, these work best on dark-burning bodies.
Saturday 11th September 2021
An Alberta Slip based black passed all the leaching tests
This is the G3914A recipe on Plainsman M340 test tiles. They were fired at cone 04 using the PLC6DS schedule. We tested them in four different caustic liquids (using the GLLE test), there is no sign of leaching on any of them. This recipe contains only 4% black stain, that is enough to stain the base GA6-B glaze to a jet black. The surface has a unique iridescence not found in any other glossy black we have used.
Saturday 11th September 2021
What is the simplest, most practical raku base crackle recipe?
Many people suffer high-percentage Gerstley Borate "bucket-of-jelly" raku recipes they find on line. Don't do this. There is a common Ferro frit that is perfect for this application, frit 3110 (Fusion frit F-75). All it takes is 15% kaolin (e.g. EPK) to produce and easy-to-use recipe that is guaranteed to craze. We have assigned it a code number of L4264, a raku base transparent recipe. We have also catalogued some common recipes that people use and outlined the issues they have: L4264A, L4264B, L4264C, L4264D. Do you need a white? It is a simple matter of adding 10% Zircopax to this.
Saturday 11th September 2021
Are frits partially soluble? Yes, many are.
These 1 mm-sized crystals were found precipitated in a couple of gallons of glaze containing 85% Ferro Frit 3195 (we have seen these with frit 3249 also). They are cubical, hard and insoluble. Why and how to do they form? Many frits are slightly soluble, the degree to which they are is related to the length of time the glaze is in storage, the temperature, the electrolytes and solubles in the water, interactions with other material particles present and the diligence of the manufacturer in mixing, correctly achieving the target chemistry and firing. The solutes interact or saturate to form insoluble species that crystallize and precipitate out as you see here. These crystals can be a wide range of shapes and sizes and come from leaded and unleaded frits. In industry this issue is not generally a problem because glazes are used soon after being made.
Context: Ferro Frit 3195, A glaze slurry precipitates flakes, G2925B glaze can precipitate crystals like this over time, Precipitated crystals from a glaze having 60% lead bisilicate frit, Ooids in Glazes, Precipitation
Friday 10th September 2021