Handling and Cleaning Decorative Glass

Above: Example of handling a decorative glass lite during installation. Photo courtesy of Window Creations and Vibrantz Technologies. 

This Glass Informational Bulletin is excerpted from NGA Glass Technical Paper FB19-25 Guidelines for Handling and Cleaning Decorative Glass. Download the complete document for free at glass.org/store. 

The following general guidelines are intended to help preserve the quality and integrity of decorative glass products and to help ensure their long-term performance. It is also imperative to consult the glass manufacturer for product specific recommendations. 

Transportation and receiving 

First, confirm that the handling equipment is adequate for the weight and size of incoming glass cases. Check shipments on arrival and document any potential quality issues (such as moisture being present) on the bill of lading prior to the driver leaving. If moisture is present, unpack the lites immediately and allow them to dry using an appropriate separating technique. Do not allow lites to remain in contact with wet protective pads. Using fans or forced cooling may be helpful in this effort. Finally, unpack lites as soon as possible to allow moisture caused by condensation to dissipate, especially if the lites have been subject to temperature changes during shipment. 

Storage 

Be sure that storage areas are dry, adequately ventilated spaces. Do not store lites in areas of high humidity, exposed to chemical fumes, or near high heat such as steam or water pipes. These conditions can promote staining and deterioration of any coatings on the glass.  

Also, store lites vertically. Do not lay lites flat. Even minor movements in a flat stack can cause surface abrasion and potentially glass breakage. Finally, when removing lites from the case, separate them from the pack one at a time before removal—do not slide lites when removing. Handle lites of glass one at a time. 

Cutting and fabrication 

Optical sensors, such as those used on automated cutting and fabrication lines, may have difficulty detecting some decorative glass substrates. To avoid risk of personal injury or damage to equipment, care must be taken first to test any optical sensors with a piece of the glass to be processed, prior to operating the equipment. 

Use clean gloves when handling decorative glass products. When handling lites with suction cups, apply cups to the flat, untreated surface. If this is not possible, extra care should be taken to ensure that proper vacuum is achieved. Keep suction cups clean and free of dust. 

Regularly vacuum or sweep cutting tables with a stiff brush to control dust and to minimize any glass grit and particles which could scratch the glass. Glass lites are cut most easily by scoring the flat, untreated side. If that is not possible, increased cutting pressure may be required. 

Individual glass lites should be washed after cutting to reduce the chance of staining from cutting oil. Porous glass surfaces (i.e., sandblasted, acid-etched, etc.) may be susceptible to marking during machine-edging. For best results: 

• Ensure that the machine’s gripping pads have been scrubbed clean. 
• Verify that the speeds of the front and back conveyors are identical. 
• Check the glass thickness with a micrometer and adjust gripping pressure accordingly. 
• Wet the glass before fabrication. 
• Wash the glass immediately after fabrication. 

Never allow coolant or cerium oxide to dry on the glass, as it may become a permanent stain on a porous surface. Decorative glass may be machine-washed or cleaned using lint-free cloths for washing and drying. Non-abrasive, mild detergents or glass cleaners that will not be harmful to the glass should be used, provided that all residue is removed and the glass is thoroughly dried. Consult glass component manufacturers for recommended washing procedures. 

Cleaning and maintenance 

As dirt and residue appear, decorative glass surfaces should be thoroughly cleaned by professional window cleaners according to the manufacturer’s guidelines. If the glass is extremely dirty, for example, because of recent construction activity, soak the glass surfaces with clean water and mild soap solution to loosen dirt and debris. Apply a mild, non-abrasive solution uniformly to the glass surfaces with a soft, non-abrasive applicator (e.g., thick cloth or sponge). Immediately dry the glass surface with a lint-free cloth. 

When the surface to be cleaned is a treated or decorative surface, special care and attention is required. 

• Follow the glass supplier’s specific cleaning recommendations. 
• Clean a small area of the glass first to verify the procedures have not caused any damage. 
• Do not use razor blades or scrapers for cleaning decorative glass. 
• Do not allow dirt and residue to remain on glass for an extended time. 
• Do not allow metal parts of cleaning equipment to contact the glass. 

If adhesives or markers are required temporarily on porous glass surfaces (i.e., sandblasted, acid-etched, etc.), test to ensure removal is possible without damaging the glass surface. Products such as silicone adhesives, mastics, felt markers, wax markers, oil and grease may result in removal issues. 

To clean glass products coated with non-ceramic paints and inks, use a soft, clean cloth, soft paper towel, or clean synthetic sponge. Use a soft cloth or squeegee for drying the surface. Do not use razor blades, scrapers, abrasive materials or chemically incompatible cleaning chemicals. Protect the glass from airborne debris during storage and inspect glass prior to field installation. Follow the manufacturers’ cleaning guidelines.