bp-COR Xtrem

This is a water-based product, designed to stop the oxidation resulting from using our act-COR or act-COR Gel oxide activator. This emulsion, which has a milky look, leaves a whitish appearance on the surface after application, which in turn will become transparent once it has dried. After about 45 minutes, the surface will be dry to the touch, although it will take approximately 24 hours for it to dry completely. Unlike our bp-COR product, using bp-COR Xtrem to treat the COR-TEN © steel means varnishes should not be subsequently used, as bp-COR Xtrem is designed to be the final coat of the treatment process for Cor-Ten steel © (apply 2-3 coats). Compared to bp-COR, the product offers greater elasticity and greater durability, hence acting as a final protective coat.

bp-COR Xtrem will protect against atmospheric agents, but not against other “accidents” such as scrapes, falling objects, spray paint, graffiti, etc. that can easily leave permanent damage to the Cor-Ten © steel. If additional protection is needed, a different treatment must be applied, using the appropriate varnish for each case.

This product is especially recommended when you need to treat large surface areas, thanks to its ease of application and the considerable savings that result, especially in large projects, as well as its low maintenance cost.

The name “stop bath” derives from the product’s original use; the pieces of COR-TEN steel, having been oxidized and in order to stop the oxidation process, were submerged in a bucket filled with the product hence “giving baths” to them, and then they were taken outside to dry. Later, the product was reformulated to facilitate its use with different application techniques such as rollers and spray guns (with compressor or turbine), etc.

VERY IMPORTANT: Please ensure to carefully read the Technical Data Sheet and Safety Data Sheet of the product to understand its correct use, both in terms of application technique to obtain the desired results, and to comply with the safety and environmental protection regulations.


No, it’s a water-based product.

bp-COR is similar to a water-based varnish, but has different application characteristics, a different drying speed and when used with corten steel, delivers improved sealing characteristics.

No, if the product is applied undiluted, it has greater hardness and durability, especially if you are going to apply stop-bath as the final layer.

This is not its intended usage; bp-COR is a water-based product and because of this, can leave small oxide particles during the drying and sealing processes.

Using stop bath as a finishing product (i.e. the final layer) can allow the treated metal to be installed in areas exposed to rain and temperature ranges of between 40-50° C and it will still be in good condition five years later.

Yes, there are different application techniques, either using a roller, a gun (turbine) or a sponge. There are courses available that provide instructions on how to apply the products. Specifically, training on how to correctly apply bp-COR, is among the most recommended.

Depending on whether the steel you are treating is located outside or inside, applying varnishes gives an “extra” to the final finish. In interior applications, varnishes will produce a finish with different shades; outdoors, the varnishes will add hardness to the stop-bath layer.

Yes, it can make a big difference. This is due to the fact on vertical surfaces, the rain drops will leave marks and, more importantly, once dry, will results in areas with rust entrainment and be more exposed. It is not advisable to apply bp-COR if rain is likely during its application. The metal to be treated must be completely dry and remain free from moisture.

This action should always be done by opening the pores of the product already applied, by sanding the surface using a fine grain abrasive and applying the product, if possible, diluted with water (50%).

It is difficult to give a precise answer, as it would be necessary to carry out multiple tests with the various products that are available. We focus on making these tests between our own products. Therefore we do not recommend using other manufacturer’s products in combination with our own.