NewsAnalysis: BACKPAINTED GLASS  
Match-Making: Adhesive Compatibility,  
Critical For Backpainted Glass  
he re-work of a backpainted glass  
installationduetoadhesivesincom-  
patibility can be time-consuming  
and costly. And adhesive incompatibility  
itself is a major safety issue.  
That’s why decorative glass fabrica-  
tors, adhesive manufacturers and coat-  
ings companies stress that installers  
use the right adhesive with any given  
glass product.  
T
“If something goes wrong, the knee-  
jerk reaction is that the coating failed,”  
says Mandy Marxen of Gardner Glass.  
But it’s not always as simple as that.  
There’s a lot of chemistry involved.”  
Jeff Nicholson, technical service  
manager of ICD Coatings, says ad-  
hesion loss and staining are the two  
most common issues that occur when  
adhesives are incompatible with back-  
painted glass coatings.This is true with  
a wide range of glazing materials.  
“Staining is primarily an aesthetic  
defect that may appear in a variety of  
ways on the glass, coatings, sealants,  
adhesives and other materials,”he says,  
noting that this could come in the form  
of streaks, lines, blotches, rings or gen-  
eral discoloration. “Adhesion loss may  
also occur between any points of con-  
tact where incompatible materials are  
in direct contact with one another or  
coexist in proximity to one another.”  
He says incompatibility of coatings  
and adhesives, or any other combination  
of glazing components,is caused or influ-  
enced by chemical reactions between the  
materials and/or environmental factors.  
These reactions may be noticeable  
immediately or they may appear over  
time in the presence of water,UV expo-  
sure and oxygen,” he says, adding that  
Coatings manufacturers, decorative glass fabricators and adhesive companies temperature and humidity can have a  
stress the importance of proper adhesive compatibility when installing significant effect on curing and may  
backpainted glass.  
contribute to other reactions.  
34  
USGlass, Metal & Glazing | August 2016  
www.usglassmag.com  
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“Backpainting is kind of a misun-  
derstood application because it covers  
such a broad array of coating types,”  
adds Jon Kimberlain, senior applica-  
tion specialist at Dow Corning.  
He says it is crucial for fabricators,  
contractors and anyone working with  
backpainted glass to maintain dialogue  
with coatings manufacturers,who usu-  
ally test for compatibility.  
ICD,forexample,conductssingle-com-  
ponent compatibility tests between a  
component and one of its coating prod-  
ucts. These tests are in accordance with  
ASTM C1087 Standard Test Method  
for Determining Compatibility of Liq-  
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This test produces a ‘yes’ or ‘no’ re-  
sult determining whether or not that  
single component is compatible with  
our coating,” says Nicholson.“It is im-  
portant to note that this test does not  
determine compatibility where more  
than one material is mixed or used in  
proximity with others—therefore, it  
is absolutely necessary for fabricators  
and glaziers to consult with the man-  
ufacturers of each individual compo-  
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Along with conf rming component  
compatibility, Nicholson says glaziers  
He also notes that his company does move. For backpainted glass specif -  
should comply with provided instruc- its due diligence when getting involved cally, read-through is a key variable.  
tions to ensure successful installations. with projects calling for a specif c coat-  
“Even though you may have a coating  
And even when using a compatible ing it hasn’t worked with in the past,“or on a piece of glass that looks opaque, if  
adhesive,it is important to pay attention if we see a coating that claims it can do light can transmit through that coat-  
to the prescribed size and spacing of the things we haven’t seen before. There’s ing, that means color can, too,” he says.  
dabs,the manufacturer’s recommended no hesitation to make a call to the coating  
cure times and conditions, etc.,”he says. supplier to f nd out where that claim is testing and material compatibility with  
Improper cure conditions may result in coming from and to fully understand it.” its customers.  
immediately noticeable failures.”  
Kimberlain says factors to consider  
“Some we approve, and some we say,  
Marxen says her company shares  
Kimberlain says one red f ag from with adhesives include the effect of ‘don’t use this,’” she says. “But when  
his perspective is when he sees re- short-term high windloads, as well as people get into the f eld and use them  
quests for a unique application that the potential of a smaller but constant anyway, that’s going to be a problem.”  
doesn’t include structural engineering. load over time to cause the material to  
—Nick St. Denis s  
www.usglassmag.com  
August 2016 | USGlass, Metal & Glazing  
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