Brock Madison Glass | Distinctive Art Glass Fixtures

Riser, what is it? and what does it have to do with my glass vessel sink?

A riser, is a round donut looking thing that is used to elevate a glass bowl above the countertop.  They are usually made of metal, but sometimes glass or even ceramic are used.  The riser elevates the glass sink bowl, thus enables easier cleaning under the glass sink.  Most risers have an integrated rubber ring that cradles and cushions the glass bowl and helps prevent over tightening of the drain assembly.

When it comes to glass sinks, what is the difference between a "Vessel", an "Undermount", and an "Overmount" style glass sink?

A Glass Vessel Sink is a glass bowl that sits on top of a counter top.  Sometimes they are also mounted in a free-standing pedestal and sometimes set into the counter top slightly.

An Undermount Glass Vessel Sink, is a glass sink that mounts on the underside of a counter top.  The glass sink is usually held in place by the sinks glass flange.  A bead of silicon seals the gap between the flange and underside of the counter top to ensure no water can get between. Undermount glass sinks are popular with people that want to under or back light their glass sink, but don't want to see the flange of the glass sink.  Though often times more difficult to install, many people feel that having the glass sink installed under the counter top, creates cleaner lines and lends more sophistication.

An Overmount Glass Sink, is a glass sink that sits on top and flush with the counter tops surface.  The glass sink has a special glass flange that sits atop the counter top and keeps the sink from falling into the hole.  Overmount glass sinks are popular with people that want to under or back light their glass sink.  With this type of mounting, you will see more of the sink.

How to install an overmount glass sink?

If you have a solid slab of some material such as granite, or you are ordering one, you might want to consider having the supplier or a professional granite installer cut the necessary hole needed to insert your glass sink into.  If the glass sink doesn't come with the size of the hole dimensions, or if it is an irregular shape and didn't come with a template for marking the hole, you or your countertop supplier need to measure the glass sink.  
The measurement you want is from the underside of the glass sink flange where it just starts to form into the bowl, minus a 1/4''.
A good way to find the sinks bowl diameter and make a template at the same time, is to carefully set the sink right side up at the exact location that it will be eventually be installed in the countertop.  If the sink does not stand on its own, you'll have to put some sort of stilts under the sinks flange to steady it.  Now find a good way to mark a line on the countertop, like a grease pencil.  Take the pencil and hold it against the bowls outer surface and follow the outer contour of the bowl, scribing the mark onto the countertop.  Now cut along this line with the appropriate tools.  You could also scribe the line onto a piece of paper or cardboard.  Cut these out and use as a template for marking the hole.

Once the hole is cut, it is time to install the glass sink.  
You will want to use good 100% clear silicon. First dry fit the glass sink to make certain it does fit and sits flush with the countertops surface.  If the fit is tight, sand or grind here and there and try the fit again.  If everything looks good, flip the sink upside down onto a soft clean towel near where it is going to be installed.  Now squeeze out a 1/4" even bead around the edge of the glass sink.  Carefully without getting your fingers into the caulk, flip the glass sink over and lower the glass sink into the hole, resting the flange of the glass sink on top of the counter top.  It is helpful to use the drain hole in the sink for a hand hold. Wipe off any excess silicon.  
Immediately after setting the glass sink in place, proceed with installing the drain pipe.   On the underside of the glass sink, using the large nut and washer supplied with the drain, carefully thread these onto the drain pipe, making sure not to cross thread the pipe with the nut.  Continue tightening the nut with your fingers till you see some silicon oozing out from under the flange.  At this point, the nut will start to feel snug, continue to "FINGER TIGHTEN ONLY"  Do not attempt to use a wrench to tighten further, as you may crack the glass sink.  The nut doesn't need to be that tight, it's just a water seal.  Wipe off any excess silicon, then let the silicon cure for 24 hours before using the glass vessel sink

How to install a glass vessel sink

Start by carefully placing the glass vessel upon the counter where it is centered under the faucet, and mark its location by tracing the hole of the drain hole in the bottom of the glass vessel onto the countertop.  Now remove the glass sink and set it aside in a safe place.   Depending on the type of surface of the countertop, will determine what type of drill bit to use to drill the hole.  If it is granite or other hard surface, a good diamond drill bit is the best for drilling.   If you are a home owner and do not feel confident enough to drill though the countertop, relax, you can probably find someone with experience and the right tools to get the job done right the first time.  Many times this might even be less money, because the diamond bits are expensive, and learning to drill may take some practice.  Experienced Plumbers may be able to do the entire glass sink installation including drilling the hole(s).  Find one with experience in installing glass sinks.  

Once the hole has been drilled or cut, it is time to set the glass sink in place.  You will need some good 100% clear silicon caulk, and a level.  
Squeeze a 3/16-1/4'' bead of the clear silicon onto the bevel of the opening.  Carefully lower the glass sink into the hole trying to maintain somewhat level.  Once in, carefully place the level on the bowls rims and proceed to level the bowl left to right, then front to back, each time centering the bubble between the marks.  Once all is level, wipe off any excess silicon that may have oozed out.  Wait 24 hours for the silicon to fully cure.
 
The drain pipe can be installed using the same silicon as the glass sink.  Just squeeze out a bead on the under side of the drains flange and seat it on the bevel of the glass sinks drain hole.  On the underside of the glass sink, using the large nut and washer supplied with the drain, carefully thread these onto the drain pipe, making sure not to cross thread the pipe with the nut.  Continue tightening the nut with your fingers till you see some silicon oozing out from under the flange.  At this point, the nut will start to feel snug, continue to "FINGER TIGHTEN ONLY"  Do not attempt to use a wrench to tighten further, as you may crack the glass sink.  The nut doesn't need to be that tight, it's just a water seal.  Wipe off any excess silicon, then let the silicon cure for 24 hours before using the glass vessel sink.