Sherwin-Williams Mordant Wash L703 (formerly known as Leighs L703/Transgard TG155) is a blue mordant solution for application onto galvanized surfaces as a chemical pre-treatment to improve the adhesion of subsequent paint systems.
When applied, this solution turns bright zinc surfaces black and this colour change can be used as an indicator that the chemical reaction has taken place and the surface is suitable for overcoating.
Endorsements
Highways Agency Item No.155.
Recommended Primers/Topcoats
Macropoxy K267 MIO Finish
Topcoats must be applied within a maximum of 2 days after application of L703
Surface Preparation
Degrease in accordance with SSPC-SP1 solvent cleaning using Degreaser W500. Weathered galvanizing should be abraded to remove the passivated surface. Where galvanizing has been exposed and zinc salt formation has occurred, the surface should be washed down with clean, fresh water to remove any soluble salts, then allowed to dry before application of this product.
Additional Notes
Drying times should be considered as a guide only.
The successful painting of galvanized surfaces is a specialised area and the choice of painting system over the mordant pre-treatment is critical. Please consult Technical Team for advice on the most appropriate paint systems for specific use.
Numerical values quoted for physical data may vary slightly from batch to batch.
