Coatings for Carbon Steel
Over the course of our thirty-five year history, steel has been our most common substrate. Our polyurethane, epoxy, acrylic and polyurea coatings have been used on literally every possible Mission Critical steel rehab application.
Typical end uses include: above and below ground field repair/rehab applications such as power poles, towers, condensers, tanks, process equipment, pipelines, transformers, exterior cladding, roofs, doors, and railings. Service conditions cover a broad range of applications from atmospheric to embedded and immersion.
Atmospheric Service
For atmospheric service, a number of formats and systems are used, depending on the industry and the anticipated service conditions.
For many applications, a Mix-and-Apply direct-to-metal aliphatic polyurethane will provide the desired service life. For longer service life in a moderately corrosive environment, use a barrier type primer such as GemThane Aluminized Primer, followed with one of the GemThane aliphatic topcoats listed at right. For more hostile environments, use our metal filled, surface tolerant GemThane Liquid Metal, either on its own (two coats) or topcoated.
For fast curing time, consider one of our single component plus catalyst products, such as Gemthane “S” or Liquid Metal; if UV stability is a priority, finish with an aliphatic topcoat like GemThane Overcote or 1:4 Aliphatic.
Gemthane now offers waterborne products as well. These low odor, low VOC, user friendly products are ideal for light to medium duty. Check out our Aquatech family of polyurethanes and acrylics.
Embedded and Immersion Service
For embedded and immersion service, there is a wide range of choice. Check out the various Mix-and-Apply products, such as CorroCote ‘S’ and Liquid Metal which are paint-like polyurethanes. Our solvent-free MG series of epoxies and our high-build GP II Field repair polyurethane product offer ease of use with zero VOC’s and outstanding performance.
Application and Performance Advantages
GemThane’s product range is very broad and, as such, offers a wide array of choices in terms of both application characteristics and performance attributes.
Some of the leading edge handling characteristics you can expect include¹:
Important performance advantages include:
¹Not all of these features apply to every product.
Surface Preparation – Traditional
Traditional surface prep has been the norm and is still the most widely accepted. The level of preparation for GemThane products is comparable to other generically-similar products. This ranges from a commercial blast to a white metal blast to power and hand tools.(SP-2 and SP-3). When blasting, the preferred blast media are traditional, with garnet, steel grit and sand being excellent choices. Steel shot and slag-based grit are discouraged. The amount of surface preparation is discussed in specific Technical Data Sheets, Application Instruction Brochures, and project specifications.
Surface Preparation – Breakthrough
The coating of previously uncoated steel and other metallic structures in the field is now faster and easier than ever before, thanks to GemThane’s industry-leading surface preparation technology. GemThane’s No-Blast chemistry offers an inexpensive, non-invasive, easy-to-use alternative to traditional abrasive blasting for the vast majority of industrial and commercial applications. Surface preparation consists simply of spraying GemThane GemBond Surface Conditioner over the surface, leaving it for 45 minutes and power washing it off with ordinary water. Gembond is a completely non-hazardous, soap-like compound that looks like car wash foam. Upon contact with metals, it immediately goes to work, literally dissolving corrosion products and oxidation, while removing contaminants and depositing a layer of Gemthane’s proprietary AP-50 Adhesion Promoter, all in a single step. When the surface is then coated with a GemThane primer or coating containing the same AP-50 Adhesion Promoter, the synergy between Gembond and the topcoat provides adhesion comparable to a commercial abrasive blast. Note that painted surfaces must be abraded before applying Gembond.
Everyday Mission Critical Maintenance Applications
The actual topcoat for a particular application is chosen based on the intended service and the desired life expectancy of the coating system. For routine exposure to normal commercial and industrial environments, GemThane’s Aquatech series offers easy to use, waterborne coatings that handle and apply similarly to latex paints. Aquatech Primer is fortified with AP-50 Adhesion Promoter. It is topped with one of two available finishing coats, Aquatech TC (acrylic-based) and Aquatech TC Ultra (polyurethane based).
A high-build, paint-like, one coat solution for routine applications is Gemthane Overcote, a solvent-dispersed self-priming aliphatic/acrylic polyurethane. This quick curing, robust product is ideal for field repair situations.
Heavy Mission Critical Maintenance Applications
For heavy duty maintenance applications, including embedded, underground, and immersion service, abrasive blasting is still the best choice. However, our new technology will still provide a performance advantage. Any GemThane base coat or topcoat containing AP-50 will achieve adhesion values about 50% higher than one would normally expect compared to a coating not containing this unique additive.
Consider starting with Liquid Metal, which contains AP-50 Adhesion Promoter, as a basecoat. Follow this with either a second coat of Liquid Metal, or use one of the following topcoats: 1:4 Aliphatic, Overcote, or GemThane ‘S’. For direct-to-metal, heavy build applications, use GP II Field Repair or two coats of CorroCote II Classic Slow Set. We’ll help you choose the right coating system based on the anticipated service conditions.