Application Guide
Jotamastic 90
Stainless steel
Abrasive blast cleaning
After pre-treatment of welds, sharp edges, removal of weld spatter and other surface contamination the surface
shall be degreased with an alkaline detergent, followed by rinsing using clean fresh water and dry abrasive blast
cleaned to create a sharp and angular surface profile using approved non-metallic abrasive media. As a guide, a
surface profile between 45-75 µm, grade Fine to Medium, Ry5 (ISO 8503-2) should be achieved.
Hand and Power Tool Cleaning
After pre-treatment of welds, sharp edges, removal of weld spatter and other surface contamination the surface
shall be degreased with an alkaline detergent, followed by rinsing using clean fresh water and hand or machine
abraded with non-metallic abrasives or bonded fibre machine or hand abrasive pads to remove all polish and to
impart a scratch pattern to the surface. Do not use high speed rotational sanders.
Concrete
Concrete should be a minimum of 28 days old, applying any coating before this time will greatly increase the
chance of the coating de-bonding. The moisture content of the concrete should be checked prior to the
application of the coating and should not be greater than 5%. Concrete substrates should be mechanically
prepared to leave a clean, sound and dry base on which a coating system can be applied.
Clean – Free of oils, grease, dust, dirt, chemicals, loose coating, curing compounds, form release oils, sealers or
hardeners.
Sound – Concrete that has unsound areas (voids, hollow spots, and friable surface) may have to be removed,
replaced or repaired with materials that are compatible with the selected coating system.
Dry – It is important to address dryness because most coatings require a dry surface for proper adhesion.
Moisture contained within the concrete that moves towards the surface through the pores of the concrete may
prevent adequate coating adhesion.
Dry abrasive blast cleaning to SSPC-SP 13/NACE No. 6. Where the concrete has become contaminated with oils,
grease, or fuels, water emulsifiable degreasers-cleaners may be used to remove these contaminants. It is
important to only clean an area that can be fully washed down after degreasing before any of the cleaner can
dry on the surface.
Ultra high pressure water jetting can be used to remove laitance and reveal blowholes and imperfections.
Ensure concrete is dry before coating application.
Blast cleaning
Dry abrasive blast cleaning to SSPC-SP 13/NACE No. 6. All prepared surfaces should then have all “blow holes”
and other surface defects filled with suitable filler that is compatible with the primer and finish coat system to
ensure that the coating can be applied over a smooth and regular substrate.
Diamond disc grinding
Diamond grind the surface to remove all laitance and expose the aggregates.
Coated surfaces
Verification of existing coatings including primers
When the surface is an existing coating, verify with technical data sheet and application guide of the involved
products, both over coatability and the given maximum over coating interval.
Over coating
High pressure water jetting surface preparation refers to ISO 8501-4, for substrates previously coated either
with a full coating system (surface DC A, DC B, DC C) or shop primer (surface DP I and DP Z). The surface
definition for existing coating (DC) refers to the degree of coating breakdown according to ISO 4628.
It is important before considering water jetting, to ensure that the specified coating system is compatible with
the existing coating system. High pressure water jetting does not remove mill scale or create surface roughness,
and is only useful for surfaces with an initial roughness suitable for the subsequent coat.
Shop primers
Date of issue: 26 August 2019 Page: 4/13
This Application Guide supersedes those previously issued.
The Application Guide (AG) must be read in conjunction with the relevant specification, Technical Data Sheet (TDS) and Safety
Data Sheet (SDS) for all the products used as part of the coating system.
For your nearest local Jotun office, please visit our website at www.jotun.com.
