Making Glass Opaque: Frit, Silicone  
Still Spandrel Products of Choice  
lass is the primary building very cold to very hot in a single day; uct used on a particular project typically  
product for accommodating [and] humidity can as well.”  
views inside and out. It is also While the frit and silicone coatings quests. In larger projects, one or the  
capable of blocking those views—with a serve similar purposes,they are applied other is usually already specified.  
little help from an opacifier.An opacifier by different processes. With frit, ce- “If they don’t specify,a lot of it comes  
is a substance added to a material, such ramic enamels are “fired” onto a glass down to the application, the process  
as glass,to make the system opaque. substrate and fused to the glass during that it’s going through or what color  
When architects want to hide fea- the tempering process. Silicone coat- they’re trying to match,” says Carlson.  
tures between floors of a building, they ings, on the other hand, are applied For instance, in a structural applica-  
depends on what the customer re-  
often specify spandrel glass, which is after tempering either via ambient cur- tion, ceramic frit may be the default be-  
fabricated to be opaque thanks to the ing or in low-temperature infrared and cause it doesn’t require edge deleting  
application of ceramic frit or silicone convection ovens.  
prior to the application of sealants or  
Catoosa, Okla.-based Tristar Glass adhesives. Silicone does.  
However, if a designer is looking to  
coatings. ICD High Performance Coat-  
ings in Vancouver,Wash., is a company has the capabilities to do both, as do  
that produces a silicone product. Ac- many glass fabricators. Rob Carlson, match an extremely vibrant color, sili-  
cording to ICD CEO Kris Vockler, sili- the company’s mechanical engineer, cone may be preferred.  
cone and frit are the only products says having a blend of the two “really  
In a standard spandrel job, it’s not  
designed for spandrel that will last“the  
wild micro-climate” that is created in  
the spandrel cavity.  
gives us the best of ideal for the two to be used together.“If  
both worlds. It gives we use one, we stick to that one. We  
us the versatility to don’t mix and match,” says Carlson.  
service our cus- “Even if the colors are very close, that  
tomers accord- color discrepancy is not worth the risk  
ing to whatever of checker-boarding the building.”  
“Organic coatings (such as latex  
paints), for example, are not a  
good choice for spandrels  
due to the micro-cli-  
mate changes in a  
they’re trying  
to do.”  
Jeff Nixon, general manager of Glass  
Coatings and Concepts in Monroe,Ohio,  
day,” she says.  
C a r l s o n which manufactures a ceramic enamel  
says that product, says durability is a key charac-  
the prod- teristic with frit.“The glass in the enamel,  
and the ceramic pigments contained  
therein,are completely lightfast,and that  
is true for every color,” he says. “They  
won’t fade, blister, peel or otherwise de-  
grade with exposure to the sun.”  
“Heat buildup  
can go from  
Vockler says one interesting aspect of  
silicone is its elasticity. “At 13 applied  
mils, the ability to pass fallout protec-  
tion testing is inherently in the coating,”  
she says.  
Carlson points out that from a fabrica-  
tor’s perspective,“it’s nice to have both.”  
They both service very well,” says  
Carlson.“Our roll coater can handle them  
equally, and switching between the two  
Ceramic frit and silicone coatings are still the prominent products used to doesn’t cause any problems or issues.”  
make spandrel glass opaque.  
—Nick St. Denis s  
USGlass, Metal & Glazing | May 2016