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GRAV is proud to be part of the scientific glass community and a tradition of glassblowing that is centuries old and still evolving. We encourage everyone to be curious and eager to learn. Our glossary helps to clarify some of the terms we use most often to talk about our products. If you'd like to better understand an aspect of glass blowing that isn't featured here, support@grav.com is ready to help.
  • Venturi Chamber

    A Venturi chamber is a glass structure that spins, cools, and aerates smoke. The chamber is shaped like a broad funnel with three evenly spaced holes pushed into the widest point of the curve. Smoke enters from the wide end of the chamber and travels toward the opening at the tip of the funnel. As smoke is pulled into the chamber, air is also pulled through the three holes. Because the air-intake holes are pushed into the wall of the chamber at an angle, they direct the smoke and air into a spinning column resembling a helix. Venturi chambers are the signature feature of all Helix products. As air is added to the smoke stream in a Helix pipe, it cools the smoke, making a smoother hit. Because hits from a Helix have a higher ratio of air to smoke compared to other pipes, they're easier for our lungs to absorb, meaning less plant matter is used per smoking session.



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  • Straight Base

    A straight base is a classic water pipe silhouette composed of a glass tube fixed to a broad glass foot. A smaller, L-shaped piece of tubing is welded to the main tube just above the foot, and bends upward at a right angle. The smaller tube is capped with a ground joint, and usually features a glass bridge connecting the joint to the main tube. The main tube extends all the way to the mouthpiece, usually with some kind of restriction, perc, or ice catcher halfway up the pipe. Straight based water pipes hold less water than beakers or round bases, but they don't require a downstem, making them easier to clean and use and simpler to pair with accessories.



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  • Showerhead

    A showerhead is a very simple type of perc consisting of a hollow glass sphere with evenly spaced openings. The perc resembles a typical showerhead, much like what you'd see on a watering can. The openings in a showerhead perc can be either slits cut into the glass while it's cold or holes pushed into the glass while it's hot. Showerhead percs break up the smoke stream and prevent large pieces of plant debris from getting further into the pipe. Because they're relatively simple, showerhead percs can scale across a range of sizes and are often used to cap downstems or in conjunction with other percs (such as in the coil showerhead water pipe).



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  • Round Base

    A round base is a classic water pipe silhouette composed of a dome of glass sitting on a flat bottom with a cylindrical mouthpiece extending from its top. The joint on a round base is set into the side of the dome, usually at a 45° angle to the pipe's bottom. Round bases can hold a large amount of water and are relatively sturdy, making them a reliable design for new and veteran smokers alike.



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  • Roll Stop

    A roll stop is a small marble of glass on the outside of an otherwise cylindrical tube of glass that prevents the tube from rolling off a flat surface between uses. Roll stops are common features on small hand pipes, such as tasters and chillums.



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  • Perc

    Perc is an abbreviation of the word percolator. Percolators use water to filter smoke by breaking up the smoke stream, removing tar from the smoke, and forcing the water and smoke into close quarters. Percs come in a variety of sizes and styles. Some percs are better for screening tar and ash. Some percs are better for cooling the smoke before it reaches the mouthpiece, but the fundamental mechanics of all percs are largely the same.



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  • Octobowl

    The octobowl is a style of GRAV® component bowl that features a glass screen across its restriction. Contrary to its name, the glass screen has six (not eight) arms branching out from a central axis. The glass screen is inserted after the rest of the bowl is finished, and then gently heated to weld it in place. The screen prevents ash and plant debris from entering the pipe. Octobowls have a glass handle extending from one side so they can be lifted safely even while hot. Octobowls are available with both male and female joints in 14mm and 19mm. They're considered an upgrade to the traditional cup and funnel bowls, and so they're paired with some of GRAV® higher-end pieces, such as Turbine and Upline water pipes.



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  • Nail

    A nail is a glass accessory used for vaporizing plant extract. All nails feature a long, thin stem capped with a flat dish. Vapor is produced by superheating the nail with a torch and applying plant extract to the top of the dish. First generation nail designs fit inside standardized female joints and require a glass dome to prevent the vapor from escaping. GRAV® nails are domeless and feature a hollow center and a raised lip around the dish. GRAV® nails are made from quartz, the purest silicate type of glass and one of the few types more heat-tolerant than borosilicate. Quartz allows the nails to be heated to the extreme temperatures needed to vaporize plant extract on contact.



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  • Mouthpiece

    A mouthpiece is the end of a pipe from which the smoker inhales. Most mouthpieces involve a hollow tube with an opening at one end, much like a straw. GRAV® mouthpieces come in a variety of forms - from the Helix Venturi chamber mouthpiece that spins and cools smoke as it exits the pipe, to the ergonomic Upline mouthpieces that are pinched to fit between a smoker's lips for greater comfort and a better seal.



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  • Lip Wrap

    A lip wrap is the outer rim of a mouthpiece and forms a seal with the smoker's mouth as they inhale. Many GRAV® lip wraps are tooled, creating a more comfortable seal and a stronger silhouette for the pipe.



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  • Ladder Perc

    The ladder perc was created by Micah Evans, a senior designer on GRAV® product development team, and is one of the signature features of the Upline collection. The perc consists of a series of stacked bubbler chambers, separated by extra-thick restrictions. Water from the lowermost chamber is pulled up with the smoke stream when the pipe is smoked, literally climbing the pipe like a ladder. Each chamber can only hold so much water, referring any excess farther up the pipe. This turns each chamber into a small bubbler, powerfully washing the smoke as it ascends. Due to its small size, relative simplicity, and the ability to incorporate it into most pipe formats, the ladder perc is one of the most efficient glass percs available.



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  • Joint

    A joint connects two separate pieces of glass. Every joint has a male and a female component that fit together, one inside the other. Joints are measured by their diameter, and the standard for the pipe industry is 14mm. 10mm and 19mm joints are also common alternatives. Standardized joints allow accessories like bowls, nails, and ash catchers to be purchased, customized, replaced, and cleaned separately. Most joints are ground, giving them a texture that creates friction between the two joint components so that they can't pull apart accidentally. Because of this texture, most ground joints have a matte, almost opaque appearance. GRAV® has begun flame polishing our joints. After they're ground, our glass artists use a torch to polish down the rough edges, keeping the useful texture but eliminating the cloudy finish. Ground joints are usually secure enough to prevent components from slipping, but joint clamps (available from GRAV® in all three standard sizes in either plastic or stainless steel) can be used for additional stability and peace of mind. Joint clamps fit around the two sides of a joint like a belt, locking them in place.



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  • Ice Catcher

    An ice catcher is a structure that holds ice in place at a critical point in a pipe, usually near the mouthpiece, where the smoke stream is about to be inhaled. GRAV® has developed an entirely new form of ice catcher: the geometric ice pinch. The pinch is made by pressing a trapezoidal tool into the outer wall of a water pipe between the base and the mouthpiece while the glass is still hot. The pinch creates a shelf that's big enough to hold ice cubes but small enough not to obstruct the smoke stream. Its sloped edges allow water to flow back into the base of the pipe, doubling as a splash guard.



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  • Honeycomb Disc

    A honeycomb disc is a very simple style of perc, found exclusively in water pipes. The disc is a round, flat piece of glass with several holes pushed through it using a tungsten rod. Because the holes are made while the glass is hot, their edges are smooth and unlikely to accumulate tar or clog easily. Honeycomb discs break the smoke stream into several smaller streams and force each of them into close quarters with the pipe's water, filtering the smoke and removing plant debris.



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  • Foot

    A foot is a glass structure welded to the bottom of a pipe to stabilize the piece between uses. While every pipe has a bottom, not every pipe has a foot. For instance, the GRAV® beaker water pipes have a flattened base, but no additional glass that would qualify as a foot. Some pipes have a single foot, usually in the form of a thick glass disc that's been flared out using a paddle tool. Other, smaller pipes have two feet, usually in the form of small glass marbles welded to the base of the pipe. This style of feet has the added function of preventing the pipe from rolling on a flat surface.



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  • Fission

    Fission is the process of splitting something into smaller parts. In the context of pipes, it usually means splitting the main smoke stream into several smaller smoke streams. The smaller a smoke stream, the cooler it becomes. Smaller smoke streams also expose a greater percentage of their volume to the internal surface area of the pipe, leaving behind more tar and ash. In pipes, fission is accomplished using percs that force a single smoke stream through multiple openings.



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  • Downstem

    A downstem is a tube that carries smoke or vapor from the bowl of a water pipe or bubbler into the water itself. Some downstems are fixed inside the pipe to prevent damage. Others are made with standardized joints and can be removed for easy cleaning. Most downstems feature some kind of cut or perc at their water end, designed to enhance diffusion of the smoke or vapor through water.



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  • Dewar Seal

    A Dewar seal is a kind of weld that positions a ground joint flush with the surface of glass to which it's connected. This positioning allows components to sit half in and half out of a pipe, increasing their stability and creating iconic silhouettes, such as the GRAV® Cup Bubbler.



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  • Carb

    A carb is a hole in a hand pipe or bubbler that regulates airflow inside the pipe. Typically, a smoker covers the carb with a finger while lighting the plant matter. Then the carb is uncovered as the smoker inhales to pull fresh air into the pipe and clear it of smoke. Larger bubblers and water pipes don't require traditional carbs. Instead of covering and uncovering a carb, the component bowl in these pipes can be removed after lighting the plant matter in order to introduce fresh air.



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  • Bowl

    A bowl is the structure that holds plant matter. Smoke is produced by lighting a bowl's contents with a flame. Some bowls are built into a pipe, like the push bowl on a GRAV® Steamroller. Push bowls are indentations in a pipe formed by pushing a tool into the glass while it's soft. Other bowls are separate components with standardized joint sizes intended to fit a variety of water pipes. Component bowls can be removed while smoking in order to clear the water pipe with fresh air. They can also be more easily cleaned and replaced when broken. Component bowls are known elsewhere as "slides", due to the fact that they're slid in and out of a water pipe during use. A bowl is also a unit of measurement, referring to one bowl's capacity for plant matter (as in "hand pipes should be cleaned after every tenth bowl smoked").



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  • Beaker Base

    A beaker base is a classic water pipe silhouette composed of a cone of glass leading from a flat bottom to a cylindrical mouthpiece. The joint on a beaker base is set into the side of the cone, usually at a 45° angle to the pipe's bottom. Beakers can hold a large amount of water and are relatively sturdy, making them a reliable design for new and veteran smokers alike.



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  • Banger

    Bangers are glass dishes attached to a small arm with a standardized male joint. They're designed for vaporizing plant extract. After a banger is heated with a torch, plant extract is applied to the dish where it instantly vaporizes. GRAV® bangers are made from quartz, which has one of the highest melting points of all glass types and can withstand very high temperatures without breaking.



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  • Ash Catcher

    An ash catcher is a structure that removes ash from the smoke stream before it reaches the mouthpiece. Some ash catchers are built into a piece, like the inverted ash catcher mouthpiece on many GRAV® hand pipes. Most ash catchers are separate accessories, like the GRAV® phoenix ash catcher, which can be paired with water pipes. Accessory ash catchers screen out ash and tar before they enter the water pipe, and have the added benefit of being easily cleaned.



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