Vitrium™ Bolted Glass-Fused-to-Steel with New Edgecoat II™ Technology


    Glass Fused To Steel Bolted Storage Tanks  – Never Need Painting

    Glass-fused-to-steel (porcelain enamel) is a single source strong, integrated porcelain enamel and steel material fused together at over 1500° F, creating a hard inert, inorganic coating that NEVER needs painting.  CST’s glass-fused-to-steel is the premium technology in the tank market.  The interior of all glass-fused-to-steel tanks feature VITRIUM™ coating technology enhanced with titanium dioxide (Ti02) for the toughest glass available. 

    CST’s VITRIUM coating is the world’s leading glass-fused-to-steel process for bolted storage tanks and has been field proven for more than 69 years.  Along with VITRIUM coating, CST now offers EDGECOAT® II, the continuous innovative EDGECOAT technology and the ONLY process in the world that provides optimum glass encapsulation on all (4) sides of the sheet edges.  VITRIUM coating features and benefits include:

    • Tough Ti02 glass formulations provides longer life
    • White interior is easier to inspect than darker coatings
    • Factory certified holiday-free sheets
    • Designed for use in both cold and hot climates
    • Designed, fabricated, shipped and supported within the USA

    EDGECOAT II is a result of CST’s commitment to an ongoing product development and improvement program.  This continuous innovative EDGECOAT technology is the ONLY process in the world that provides optimum glass encapsulation on all (4) four sides of the sheet edges.  CST took the best EDGECOAT technology in the world and made it better with EDGECOAT II.

    Following Porcelain Enameling Institute guidelines (PEI-101), EDGECOAT II sheets are mechanically rounded to specific radii that provides maximum glass adhesion to steel.  The combination delivers the maximum corrosion resistance of VITRIUM glass coating with the greatest protection on every sheet.

    • Highest quality finish
    • Glass is applied on all (4) sides of the sheet offering the greatest protection
    • No sharp edges on tank sheets, eliminating safety hazards
    • Edges are engineered to ensure optimum radii for each individual gauge of steel providing the maximum and consistent glass edge
    • 5 mils of glass encapsulation on every sheet edge

    Download Edgecoat II Technical Data Sheet

    VITRIUM is our proprietary titanium Dioxide (TiO2) glassing process applied in a 3-coat, 1-fire (3c1f) process procedure. VITRIUM coating is also produced in a 3-coat, 2-fire (3c2f) process primarily when special colors are requested or thicker layers of glass are required.

    The CST proprietary VITRIUM glass-fused-to-steel process provides:

    • Longer tank life
    • Base coat of glass frit containing nickel oxide ensures consistent quality
    • Maximum coating effectiveness without requiring excess coating thickness in order to provide the needed durability at competitive pricing
    • Unique process technologies and voltage testing on all interior side wall sheets provide a factory certified 100% holiday free surface.

    The combination of glass quality and glass thickness provide the assurance that over 69 years of experience and over 100,000 structures successfully installed around the world will continue with each and every new structure installed.

    Titanium Dioxide (TiO2)

    In 1998 CST, formerly Engineered Storage Products, launched an R&D project to develop a process for the direct application of our proprietary Titanium Dioxide (TiO2) Glass.  The result is a totally new, patented “3-coat, 1-fire” (3c1f) process for applying TiO2 Glass.

    TiO2 is a very common ingredient used by many coating manufacturers for various reasons:

    • titanium-oxide glass-fused-to-steel
      • It is considered inert and at high level in porcelain enamel, gives unique properties.
      • In the case of the interior VITRIUM coating, with its higher percentage of TiO2 in the final white layer, allows CST to provide an exceptional enamel surface.
      • During firing, the white layer’s higher viscosity has the effect of controlling bubble structure in addition to making the top TiO2 rich layer harder, more chemical resistant and the bubble structure finer.  This high TiO2 content is unique to AQUASTORE® and provides exceptional properties to fit colder conditions common to the North American market.

    As a result of using higher amounts of TiO2 in the final white layer, a unique visual marker on the glass known as “VITRIUM threading” becomes apparent.  This is caused by thicker areas of the top white layer interspersed with thinner areas allowing the underlying bluecoat to show through opaquely.  This immediately identifies the coating as VITRIUM.

    Manufacturing Excellence

    CST’s DeKalb facility is ISO 9001:2015 quality system certified.  Engineers design tanks for a wide range of standards including AWWA D103 Standard for Bolted Steel Water Storage Tanks, AISC, FM codes and NFPA Standard 22.  Additionally, glass coatings meet ANSI/NSF Standard 61 requirements for indirect additives, making AQUASTORE®, HARVESTORE® and SLURRYSTORE® tanks ideal for liquid, feed, manure storage and digesters processes.  Most importantly, extreme pride is taken in craftsmanship for a tank that endures the test of time.

    From the automated manufacturing processes through the stage-by-stage inspection and even down to careful inspection of the glass. Our glass-fused-to-steel quality is the best in the industry.  The best proof of the precision of CST’s manufacturing procedures can be seen in the thousands of tank installations around the world.

    Glass-Fused-To-Steel Process

    Glass-fused-to-steel is the premium technology in the tank market.  The factory-applied silica glass coating on AQUASTORE, HARVESTORE, SLURRYSTORE and NUTRISTORE tanks forms a hard, inert barrier for both the interior and exterior tank surfaces to guard against weather and corrosion.  Glass-fused-to-steel is impermeable to liquids and vapors, controls undercutting caused by corrosion and offers excellent impact and abrasion resistance.  The color won’t fade or chalk and most graffiti can easily be removed.  It NEVER needs painting!

    • blast-furnace glass fused to steel

      • Fabricated sheets are grit blasted to a uniform, near-white surface
      • Proprietary formulations of borosilicate, minerals, water and clays are blended into a sprayable slurry called “slip”
      • After inspection, the slurry is fused to the steel sheets at temperatures above 1,500° F to produce the distinctive glossy Aquastore finish
      • The molten glass reacts with the profiled steel surface to form an inert, inorganic chemical and mechanical bond

    VITRIUM Coating Glass Finish

    New process technology has resulted in the development of CST’s newest glass innovation – VITRIUM coating.  This coating combines the outstanding chemical and physical resistant properties of Titanium Dioxide (TiO2) saturated glass with a highly engineered ultra-fine glass structure surface to create a high-performance glass-fused-to-steel technology.  VITRIUM coating features and benefits include:

    • Tough TiO2 glass formulations provide longer life
    • Electrostatic base coat application ensures consistent quality
    • Maximum coating effectiveness without requiring increased coating thickness
    • Unique process technologies provide factory certified “holiday free” sheets
    • Process efficiencies lead to competitive pricing
    • Ideal for both cold and hot climates

    Color Options

    AQUASTORE glass coatings are available in standard cobalt blue or four other premium exterior colors.  Forest green, sky blue, desert tan or white premium colors are available at an additional cost. Inquire for custom colors.

    color-options_Glass fused to steel_CST

    History of Glass-Fused-To-Steel

    CST (formerly A.O. Smith) first discovered the methodology of controlling corrosion by fusing glass to steel in the 1930s.  The technology was initially used in the brewing and hot water heater industries.  While other uses for glass-fused-to-steel were explored, the first glass-fused-to-steel tank went into service in 1949 as a HARVESTORE silo.  This agricultural use to store feed while retaining quality has been widely used for almost 69 years.

    In the 1970s, our Municipal and Industrial Division was formed and we subsequently launched AQUASTORE tanks for water, wastewater and other industrial liquid uses.  Since 1930, more than 100,000 AQUASTORE, HARVESTORE, SLURRYSTORE and NUSTRISTORE glass-fused-to-steel tanks have been installed in over 70 countries around the world.


    Tanks with a VITRIUM glass-fused-to-steel coating are ideal for the following applications:

    Process Water

    Tanks with VITRIUM coating are specified when potential contamination of the liquid from rust is as much a concern as durability.  For the long lasting coatings, only a VITRIUM coating will do. 

    Potable Water

    AQUASTORE is the top choice in rural water potable water tanks and quickly becoming the choice for urban water applications as well with capacities from 100,000 gallons to over 6,000,000.

    BioEnergy/Anaerobic Digesters

    With over 30 years of experience and field-tested results, tanks with VITRIUM glass-fused-to-steel coatings have proven that they can provide the desired characteristics of stainless but at a lower cost.


    When durability and total life cycle cost are the driving factors in wastewater tank selection, VITRIUM coating on tanks are the choice from clarifiers and SBRs to aeration and leveling tanks.

    Composite Elevated

    The only thing worse than having to come up with the funds to repaint a tank is having to do it to a tank 100 plus feet in the air. An AQUASTORE is not painted and never needs repainting.


    With a proven track record of over 20 years in service without degradation to the interior of the tank, VITRIUM coated tanks can withstand the rigorous environment of landfill leachate storage applications at a fraction of the cost of stainless steel.



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