Weathering Steel

GemThane offers a unique alternative when coating weathering steel in the field (the red structural steel often known by the trade mark “Corten”).

Historically, this type of steel must be aggressively blasted in order for coatings to adhere properly. This is no longer necessary. When GemThane protective coating researchers were developing the No-Blast GemBond® technology for field coatings of galvanized structures, it was discovered that the same new coating product gives equally outstanding results on weathering steel. Simply applying GemBond Surface Conditioner, followed by one of several GemThane coatings, will produce adhesion in the 1,500 to 1,800 p.s.i. range. The system is suitable for heavy duty and severe service, not just routine atmospheric exposure.

The one step GemBond process (spray on, wash off) provides a far more uniform and predictable result than blasting (with its many variables) at a dramatically lower cost. GemBond dissolves oxidation, removes contaminants and deposits a layer of Madison’s unique AP-50 Adhesion Promoter, all in one easy step. This simple process will provide results comparable to a commerical metal blast with abrasives.

If you prefer to blast for some reason (e.g. required by specification or to remove an extremely heavy layer of corrosion product), the use of GemBond subsequent to blasting will increase adhesion by 50% or more, especially where the blasting equipment, media and other factors are not optimal.

Think then of GemThane GemBond in two ways, as a way of cutting back on the blast and as a way of eliminating it altogether when doing field repair/coating jobs.

The GemThane product line includes paint-like Mix-and-Apply aromatic corrosion coatings, similar format of aliphatic (color stable) coatings and Liquid Metal product. We also have two component aromatic products. GP II Repair is a solvent free high build one coat system and CorroCote II Classic Slow Set is a solvent-based medium build aromatic system used to repair the embedded area and/or to repair damaged coating below grade.

GemThane Aromatic and Aliphatic topcoats are self priming and are typically used as one-coat systems. GemThane Liquid Metal can be used on its own or top-coated with a Mix-and-Apply finish coating such as OverCote, or 1:4 Aliphatic coating such as PC Aliphatic.

Note: Areas of heavy rust build-up need to be mechanically removed either by abrasive blast, or by power tools, prior to using GemBond.