To achieve good dimensional accuracy, it seems that I should scale up the model by 13% in all axes, then set the special ceramic resin scale factor to 1.045 (additional 4.5%)
Note: I printed the cube at double scale, so it measures 20mm on an edge.
The egg was printed directly on the base plate with no supports. The calibration cube was printed on supports to avoid measuring the compressed starting layers.
Are these printed model being bisque fired yet? if so, are you following the official firing schedule?
btw, NICE work!
Yes, I should have mentioned that the items shown in my post were fired according to the official recipe (max temp 1260 C). They have not been glazed. It seems the first ramp (going up to 240 C, and holding there is the most critical part. After the resin has been burned away, you can go up faster to the ceramic sintering temperature.
Great work. Also, great videos on YouTube
This is genuinely useful info.
does this ceramic ONLY sinter? Or does it fully vitrify?
My applications would all require a non-porous result.
The firing schedule temperature we’ve included in the user guide (1271°C) will cause the Ceramic material to densify to the point where it does not have interconnected porosity.
You can also “bisque fire” at a somewhat lower temperature (1125°C) to create a (relatively fragile) porous ceramic, and then glaze the part to create a non-porous object.
I glazed these parts with Amaco “Celebration” high-fire glaze. I dipped the egg once in full-strength glaze, and let the excess run-off. The glaze is very thick, and actually closed up the holes in the egg as it was draining off. I used a can of compressed gas duster to open the holes back up.
I brushed the glaze onto the cube with a tiny paintbrush. It applies very easily, and sticks to the surface well. I used a heat gun to dry the glaze in a few minutes.
I fired the pieces until my kiln’s thermocouple reported 1220C. The thermocouple is near the roof of the kiln, and I know this spot is about 25C hotter than the floor where the objects are. The glaze instructions indicated it should be fired to cone 5 (1195*C). However my small kiln rises in temperature very quickly, so the glaze may not have had time to fully melt. I’ll have to try some slower temperature ramps.
I’m pretty happy with the colors (Orangerie and China Blue)! Now, just to get more control / consistency of the gloss level.
Hello! Great looking prints. I’m strongly considering getting into this ceramic workflow. I’m looking at your glazed prints and see what looks like a hint of a rough surface. Is it possible to get a perfectly smooth and shining finish with this stuff?
russena, I’ve done some ceramics in high school, but it’s been a while, and I’m re-learning some of the basics. Once the 3D-printed ceramic piece is fired it should hold glaze like any other hand-thrown piece of porcelain, however the surface tends to have a fine sand-like texture, which is a little different than the finish left by smoothing with a chamois cloth, or soft sponge. This is my first time using high-fire glazes, as well. I added more glaze to the parts, and re-fired. This time, it is all glossy, but the glaze itself is still relatively uneven (photo). Overall, I’m very happy with the progress!
this sounds like it still has some porosity… that is- it does not form a glass, like porcelain?
Not to go too far off topic here, but has anyone notised any residue in your kiln from the initial burnout pgase?
I would be using a friends glass kiln to initially fire parts in, and since he works with glass, he is concerned about particulate contamination and ourgassing from the initial resin burnout.
Anything noticed by anybody?
I haven’t noticed any problem in my little Paragon Firefly. I leave the lid cracked open about .5" during the first ramp and hold (to 240ºC) for ventilation and then close it for the second ramp up to the sintering temperature. Then again, I fire all sorts of stuff in that little kiln (clay, PMC, glass, etc.), and haven’t had any problem with contaminating glass. I just vacuum it out in between firings (mostly to make sure I don’t get any particles of stuff stuck in the coils–especially important for firing kinds of PMC that have to be fired in granulated carbon to produce a reducing atmosphere).
I see. Looks like there will be some technique involved in getting things glossy AND uniform. But still very cool. Can’t wait to see more!
