Finally, the numerous holes don’t create much drag, so you can consistently get a perfect hit without being slowed down. Depending on the size of the holes of the perc, water may sit on top, or always fall through just to pull water up through the perc when you hit the piece. As long as water flows through it, it doesn’t matter if water is sitting on top of it or not. Inline percolators are simple slitted tube percs, similar to downstems.
However, unlike downstems they tend to sit flat in the water, whereas downstems typically enter the water at an angle, so they don’t have the problem of some slits being higher than others. This means the only limit to the number of slits is the length of the tube, which is why it’s fairly common for tubes using large inline percolators to be expanded horizontally, like the piece in the image on the left, to accomodate longer inline percs. Although this makes them more effective, the longer the perc, the easier it is to break. Much like showerhead percs, they are often used in stemless pieces as the first minor percolator which then leads to the first main percolator above it. Matrix percolators, sometimes called Birdcage, have become a lot more common lately. I normally wouldn’t give them their own category since they’re essentially the same as stacked showerhead percolators, but their prevalence has earned them their own category. They basically function the exact same way as a stack of showerhead percs. Much like stacked showerheads, the top rows have less resistance and therefore make the lower holes less likely to pull any smoke through. This means that a one-row showerhead with more evenly distributed slits can be more effective than a matrix percolator with far more rows and holes.
Even though they don’t provide any significant functional advantage, their aesthetic makes them desirable, as they appear to provide more percolation than they really do, although they still do an adequate job regardless. Turbine Percolators are another great disc percolator. Similar to honeycombs, their low height makes them easily stackable, and the fact that they are one solid piece makes them incredibly durable, not to mention easy to produce. The percolation power is similar to honeycomb percolators, however with larger and fewer holes, they provide a bit less percolation power. First, if you pull through them at the right speed you get beautiful cyclone effect, as seen on the left. The cyclone effect throws the water up along the edges of the piece rather than up through the middle, making turbine percolators function as effective splash guards, especially if the walls above the perc hit a ceiling where the tube turns into a smaller tube for inhaling the smoke. Sometimes turbine percolators are used exclusively as splash guards and see little water pass through them, although we like to see at least a little bit of water goes through them both for the cyclone effect as well as the percolation power. Fritted Disc Percolators are the kings of percolation power. There’s simply no other percolator that comes close to what a fritted disc can do. The number of bubbles, and therefore surface area of those bubbles, completely dwarfs all other percolators. Additionally, it has the durability and stackability advantages that all disc percolators have. However, there are two significant downsides that come with fritted disc percs. First is that the microscopic holes can be difficult to draw through because they create a lot of drag. Additionally, all those little pores can easily get clogged, meaning you’ll have to do maintenance more often than at least once every couple of weeks if you’re using it often. However if you don’t mind the drag, and you regularly clean your glass anyways, then this could be the perc to end all percs. Coil / Spiral percolators are among the least talked about as well as the least understood. They are simply a coiled tube with a hole at the end, so what exactly makes this any different than a simple downstem? First, the obvious difference is that they are more visually interesting. Glassblowing is an art, so many people look for aesthetics as much as function in their glass. The more useful difference is the length of the tube. Because the tube is coiled, you can coil 10″ / 25cm of tubing into a 2″ / 5cm vertical space. This forces the smoke to travel a longer path, increasing the cooling power of the percolator.
However, when compared to other percs in terms of function, they aren’t nearly as effective.
They may be better at cooling off a hit than most other percs, so if you value that over other features, you may like spiral percs. Or maybe you have 3 honeycombs and a fritted disc and you just want to add something different for your ashcatcher, then having a spiral could make sense. Although they aren’t our favorite percs on their own, they definitely have their place.