Frameless Windows (Bonded Glazing)
Frameless windows are popular these days because they look modern, sleek and alluring on the side of a vessel.
They're also thought to be a cheaper option, because there is no frame... however, there are a few hidden costs and other things to take into consideration when looking at bonded glazing on your vessel.
There are two options for installation of bonded glazing... 1. gluing the glass directly over the window opening and using adhesive/sealant to finish the edges or 2. creating a rebate for the glass to be glued into so it sits flush with the side of the boat... SeaMac strongly recommends the second option.
You might think gluing the glass directly over the window opening is the easiest and cheapest option, and it is, but it comes with high risk. Toughened glass is incredibly strong, but it's weakness is around the edges. If you have 6mm toughened glass, then it is estimated 6mm of the outer edges is not toughened because the toughening process occurs as the glass cools after being heated to more than 600°C, and the edges cool down quickly first. Likewise, 8mm toughened glass has an 8mm weakness around it's edges, 10mm toughened glass has a 10mm weak zone, and so on.
When you frame this glass, as with a SeaMac Fixed or Large Fixed Window, there is no risk as the edges are protected by the frame. However, when you glue glass with exposed edges directly onto the vessel you leave the edges vulnerable to being chipped, which is a safety risk as well as a costly exercise.
SeaMac recommends you prepare a rebate for the glass to sit in so that the finish is flush with the sides of the vessel and the edges are protected. However, this option requires more prep work by the boat builder to prepare and finish a rebate for the glass to be glued into. Most boat builders we talk to say that the extra labour involved in preparing the rebate can negate the cost of the frame.
We also strongly recommend ceramic banding around the edges of the glass, which hides & protects the adhesive from UV damage, and finishes the look by framing the glass. This ceramic band can be made as wide as you need it to be.
So whether you decide to go with bonded glazing or framed windows really comes down to personal preference and desired look, at the end of the day, rather than a cost saving.