High Performance Corrosion Resistant System for Plastisol Coated Metal Cladding - Issue 1 Surface Preparation & Cleaning Application of Patch Primer to Corroded Areas Application of Primer to Patch Primed & Exposed Metal Areas Finish Coat(s) As required 3M Scotchkote Epoxy Primer MC 135 @ 50µ Theoretical coverage rate at 50µ is 10m²/litre 3M Scotchkote Epoxy Primer MC 135 @ 50µ Theoretical coverage rate at 50µ is 10m²/litre 3M Scotchkote Encapsulation Coating Polynox 136 @ 350µ Theoretical coverage rate at 350µ is 2m²/litre If applied in accordance with this Application Guide, has an expected service life of 10 years. 1
Surface Preparation & Cleaning Heavy deposits of dirt, silt and other contamination should be removed from the surface. All surfaces should be high-pressure detergent washed to remove all dirt, debris, oil, diesel and other contamination. The adhesion of the existing paint system to the substrate should be checked using the V Cut Procedure - Using a sharp knife the coating should be cut through to the substrate making two cuts in the shape of the letter V. The knife should then be inserted at the point of the V and flicked upwards to test the adhesion. If no coating is removed, or the coating splits cohesively, leaving a layer of coating on the surface, then the adhesion of the system can be considered suitable for overcoating. Any areas of loosely adhering coating or loose flaking paint must be scraped away to provide a firm sound surface. Surfaces of the existing coating should then be thoroughly abraded, with edges feathered in, then wiped/ rinsed to remove all dust and abrasive residue. All corroded areas should be thoroughly prepared by wire brushing and/or angle grinding to achieve ISO 8501-1 St3. All prepared corroded areas should then be patch primed with 3M Scotchkote Epoxy Primer MC 135 as described later in this guide. Any white zinc salts should be removed by light abrasion or scouring with 3M Scotchbrite abrasive pads. The use of a proprietary Mordant Solution/T Wash is recommended on Zinc surfaces. When used as directed by the manufacturer s instructions, this will provide a useful indicator of surface cleanliness as well as etching the surface. When used correctly the surface should turn blue/black. If this doesn t occur then the surface should be cleaned again and the Mordant Solution reapplied. 2
Patch Priming Corroded Areas With 3M Scotchkote Epoxy Primer MC 135 Surfaces to be coated should be dry and free from contamination. Scotchkote Epoxy Primer MC 135 is a two component high performance epoxy coating, supplied as a Part A (Base) component and a Part B (Activator) component. The Part A (Base) component should be thoroughly stirred until a uniform colour is produced. The Part B (Activator) component should then be added and thoroughly stirred for at least two minutes, to produce a homogeneous mixture. NOTE: If only part quantities of the Part A (Base) and Part B (Activator) are to be used, care must be taken to maintain the volume mixing ratio of 3:1 respectively, as well as total compliance with the above mixing procedures. Scotchkote Epoxy Primer MC 135 should not be applied when the temperature of the substrate is less than 7 C and/or when the surface to be coated is less than 3 C above the dew point. Scotchkote Epoxy Primer MC 135 should be applied by brush, ensuring the product is worked well into pitted areas, at a wet film thickness of 100 microns, which equates to a dry film thickness of 50 microns on a smooth surface. Theoretical coverage at 50 microns is 10m²/litre. These patch primed areas can be overcoated with the subsequent primer coat after they have achieved a touch dry state, typically a minimum of 4 hours at 20ºC and provided surfaces are clean, the maximum overcoating time is three months. 3
Application of 3M Scotchkote Epoxy Primer MC 135 to Patch Primed Corroded Areas & Exposed Metal Surfaces Areas that have been previously treated with Scotchkote Epoxy Primer MC 135 should be allowed to become at least touch dry before applying the subsequent coat. Non-ferrous metal surfaces need only thorough cleaning and degreasing, no mechanical preparation is normally required. Scotchkote Epoxy Primer MC 135 should be applied by brush, roller or spray, at a wet film thickness of 100 microns, which equates to a dry film thickness of 50 microns, to produce a smooth uniform film. Theoretical coverage at 50 microns is 10m²/litre. Scotchkote Epoxy Primer MC 135 can be overcoated after a minimum of 16 hours at 20 C and provided surfaces are clean, the maximum overcoating time is three months. The following times are given as a guide for minimum overcoating at different temperatures. TEMPERATURE MINIMUM 10 C 32 hours 15 C 24 hours 20 C 16 hours 25 C 12 hours 30 C 8 hours 4
Application of 3M Scotchkote Encapsulation Coating Polynox 136 Scotchkote Encapsulation Coating Polynox 136 should not be applied when air and surface temperatures are below 7 C, when rain is falling or when rain is imminent nor when relative humidity exceeds 85% or when the surfaces to be coated are less than 3ºC above the dew point. Prepared surfaces should be clean and dry. Scotchkote Encapsulation Coating Polynox 136 is a single component water based anti-corrosive coating supplied ready for use, only requiring stirring to incorporate any slight separation prior to use and is ideally suited for application by airless spray or air assisted spray. For both methods of spray application a minimum of 32:1 pump ratio should be used ensuring that a spray pressure at the tip of 2500-3000 psi is achieved. Spray tips in the range of 15-19 thou should be used. During application all crevices should be completely penetrated and coated, particularly edges and angles of sectional steel. During application, regular checks should be carried out using wet coating thickness gauges. Scotchkote Encapsulation Coating Polynox 136 should be applied as evenly as possible at a nominal 600 microns wet to produce a minimum dft of 350 microns. Excessive wet film thicknesses should be avoided. The theoretical coverage at 350µ is 2m²/litre. Scotchkote Encapsulation Coating Polynox 136 can also be applied by brush but will require multiple coats to achieve the required minimum dry film thickness. An appropriate drying interval must be left between the coats, dependant upon prevailing temperature and humidity levels. After application the surface should be inspected and any visible areas of uncoated substrate must be coated to the correct film thickness. To maintain the specified thickness at edges and around other sharp protuberances, a stripe coat should be applied to these areas prior to carrying out the overall application. The stripe coat can be applied by brush or spray. In open conditions with good air movement Scotchkote Encapsulation Coating Polynox 136 is touch dry in approximately 60 minutes and hard dry in 24 hours at 20 C. In cold and humid conditions these drying times will be considerably extended. 5
Notes Document References 3M Scotchkote Epoxy Primer MC 135 3M Scotchkote Encapsulation Coating Polynox 136 Product Technical Data Sheet 3M and Scotchkote are trademarks of 3M Company. Important Notice: All statements, technical information and recommendations are based on information believed to be reliable, but the accuracy or completeness is not guaranteed. Before using the 3M Scotchkote Product, you must evaluate it and determine if it is suitable for your intended application. Because conditions of product use are outside of 3M control s and vary widely you assume all risks and liability associated with such use. Any product related statements not contained in current 3M publications, or any contrary statements contained in your purchase order, shall have no force or effect unless expressly agreed to in writing by an authorised officer of 3M. Warranty; Limited Remedy; Limited Liability 3M warrants that the 3M Scotchkote Product will conform to 3M published specifications upon shipment. If the product is proven not to have met the specifications your exclusive remedy within 12 months of sale by 3M of the product and 3M's sole obligation will be, at 3M's option, to replace the Product or to refund the purchase price of the Product. Except where prohibited by law, this warranty is made in lieu of all other warranties, express or implied, including, but not limited to, any implied warranty of suitability or fitness for a particular purpose, or those arising from a course of dealing, custom or usage or trade. 3M has no obligation under this warranty with respect to any product that has failed due to inadequate or improper storage, handling, surface preparation, application, or maintenance; failure to follow product instructions or recommendations or alteration or damage to the Product caused by accident, neglect, or misuse. OTHER THAN IN THE CASE OF DEATH OR PERSONAL INJURY CAUSED BY ITS NEGLIGENCE AND EXCEPT WHERE PROHIBITED BY LAW, IN NO EVENT SHALL 3M BE LIABLE FOR ANY DIRECT, INDIRECT, SPECIAL, INCIDENTAL OR CONSEQUENTIAL LOSS OR DAMAGES (INCLUDING LOST PROFITS) ARISING FROM THIS PRODUCT, REGARDLESS OF THE LEGAL THEORY ASSERTED. Electrical Markets Division (EMD) 3M United Kingdom plc 23 Standard Way Industrial Estate Northallerton North Yorkshire DL6 2XA United Kingdom Phone: +44 (0)1609 780170 www.3m.co.uk/scotchkote Electrical Markets Division (EMD) 3M United Kingdom plc 3M Centre Cain Road, Bracknell Berkshire RG12 8HT Phone: 01344 858000 Fax: 01344 857970 www.3m.co.uk Please recycle. Printed in UK. 3M 2014. All rights reserved. - 03/13 6