Ever wondered how ceramic tile is made? It is a remarkable process and the technology behind that process has moved forward in tremendous leaps during the last 15 years. I took all the photos in this post and I asked one of my new best friends, Ryan Fasan with p.a.t.t.i. tile, to help with the technical details. I was listening but instead of taking notes, I was taking pictures. Ryan is a serious expert on all things related to tile and he was gracious enough to agree to fill in the gaps for me.
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Keraben Ceramica was nice enough to give us a guided tour of their production facility in Castellon, about an hour outside of Valencia. The production lines were running full-steam, letting us get a first-hand look at the processes. Thankfully we had their production manager and a couple technicians to help our traveling experts Patti Fasan and Ryan Fasan explain what we were looking at (ooh look …. that’s tile. Look over there, more tile. Is that tile?)
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After walking the entire length of the factory (a few football field’s distance) we started our tour off at the beginning – the presses. Above, you can the recessed and movable die (like a tray) where the atomized clay mixture will be loaded. This clay mixture contains just enough moisture to allow it to keep it’s shape after compaction.
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Once the clay has been set in place, around 10,000 tons of compression comes down and forms the actual tile. The bottom die lifts up and an arm gently pushes all 6 greenware tiles (greenware = non-fired tile) to the conveyor heading off to the glazing lines. In order to keep the delicate greenware tiles from having to be handled much, the entire production line moves the tiles in a straight line from begining to end.
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The first glazing step for all quality tiles is an engobe coating delivered by a bell or waterfall application (this is essentially a primer coat of glaze). Functioning just like a primer paint, engobe glazes give a clean white surface that is easy for the more finicky finishing glazes to adhere.
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Next it was time to actually decorate the surface of the tile. For this collection Keraben uses the Roto-color glaze delivery system with multiple glaze rollers creating nearly limitless variation in their stone reproduction.
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As the tiles pass beneath the rollers, each one gets a different segment of seven different screens which creates a very realistic reproduction of natural stone. Depending on the number of rollers in the production line, an almost infinite amount of variation can occur.
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Here’s a good look at one of the drums actually applying the glaze. The lighter colored stripe in the center of the drum is the screen, which is in constant motion so that each tile gets a different segment of the drum in different areas of the tile.
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Another close-up view of one of the screening drums.In the bottom right hand of this picture, you can see a bucket of glaze. Each one of these rollers applied a different color and screen of glaze creating a deeply varied pattern on the tile. To keep the frits and minerals from settling in the glaze, each glaze bucket is kept in constant motion by a rotating arm (seen attached to the side of the bucket).
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After the tiles have received their glaze, the sides of the tile are gently brushed to ensure grouts can adhere to the body of the tile during installation.
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In this picture, the tile passes under high-heat lamps to help dry off the excess water from the glaze before it gets absorbed into the bisque. This step is so that the tiles don’t deform or explode in the high heat of the kiln.
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Once the tile makes it through the glazing lines they are grouped together and arranged and placed in massive drying cubes. This is to ensure that as much moisture as possible is drawn out of the biscuits prior to firing.
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Before the kilns is a massive amount of these pre-dried tiles waiting to be fired. The kiln is the most sensitive and expensive to run, piece of equipment in the factory. They don’t want it to ever have to shut down or run empty. The recalibration time and resource expense is horrible so a factory will always have a platoons of tile ready to fire to ensure this doesn’t happen… these cubes-o-tile are moved around the facility by robotic forklifts. We did find out they automatically stop for people… on multiple occasions.
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Finally the tiles make it to the roller kiln, a massive natural gas powered furnace that bakes the tiles at temperatures up to 2200 degrees Fahrenheit (1200 degrees Celcius) the white tubes you see there are industrial porcelain rollers from which the kiln gets its name. They are virtually the same material as is used to clad the space shuttles as it is the only thing that will withstand prolonged exposure to the white-hot heat of the kilns.
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This was most people’s favorite part of the tour because it was the only part that had even a little heat to it. Even though it looks like you’re staring into the depths of hell there, the amount of heat given off is so minimal- a testament to the efficiency of a good ceramic kiln. Any heat-loss is wasted energy and Spanish ceramic production prides itself on its efficiency and environmental responsibility.
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I both love and hate Bob for getting this shot. I’ve never been able to get a shot this good of this section of the kiln. I said white-hot and I meant it. This is the sintering point of the kiln, where the feldspar fuses with the sand and clay creating an inert and immutable ceramic tile. Even at this hottest point in production you can touch the ceramic rollers and they are merely warm to the touch… usually. I wouldn’t advise trying it out unless someone at the factory says it’s ok.
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Here’s our amazing Reign in Spain group with our Gracious host Javier from Keraben in the bottom left frame. Ryan is the incredibly happy looking fellow in the upper left hand coner and I am the guy who is obviously trying to look like an architect on the furthest right hand side.
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