Surface Preparation (Sanding)

User Rating:  / 1
PoorBest 

The performance and durability of any paint coating are significantly affected by the surface preparation carried out. This is even more important in the case of steel structures, where the selection of the method of surface preparation is crucial in any corrosion treatment.

Different types of surface preparation can be selected depending upon the condition of the substrate, the paint system selected, the exposure and required durability of the coating, economic and environmental considerations etc.

Some of the more common methods used on carbon steel with or without coating, galvanised steel, aluminium and light alloys, namely, dry blast cleaning, hand and power tool cleaning, water jetting, degreasing.

The practical performance of the paint coatings is significantly affected by the condition of the surface prior to painting. The main relevant factors are:

  1. Presence of rust and mill scale
  2. Presence of contaminants: salts, dust, oil and grease
  3. Surface profile

ISO 8501 provides a method of making a visual assessment of the cleanliness of surfaces and is commonly used to determine paint systems. This standard is divided into 4 parts.

  • ISO 8501-1:2007 – Rust grades and preparation of uncoated steel substrates and steel substrates after overall removal of previous coatings.
  • ISO 8501-2:2001 – Preparation grades of previously coated steel substrates after localised removal of previous coatings.
  • ISO 8501-3:2007 – Preparation grades of welds, edges and other areas with surface imperfections.
  • ISO 8501-4:2006 – Initial surface conditions, preparation grades and flash rust grades in connection with high pressure water jetting.

Preparation by Blast Cleaning

  • Sa 1: Light blast cleaning. Loose mill scale, rust and foreign matter must be removed. The appearance shall correspond to the prints designated Sa 1.
  • Sa 2: Thorough blast cleaning. Almost all mill scale, rust and foreign matter must be removed. Finally the surface is cleaned with a vacuum cleaner, clean dry compressed air or a clean dry brush. It must then correspond is appearance to the prints designated Sa 2.
  • Sa 2½: Very thorough blast cleaning. Mill scale, rust and foreign matter must be removed to the extent that the only traces remaining are slight stains in the form of spots or stripes. Finally the surface is cleaned with a vacuum cleaner, clean dry compressed air, or a clean dry brush. It must then correspond in appearance to the prints designated Sa 2½.
  • Sa 3: Blast cleaning to pure metal. Mill scale, rust and foreign matter must be removed completely. Finally the surface is cleaned with a vacuum cleaner, clean dry compressed air, or a clean dry brush. It must then have a uniform metallic colour and correspond in appearance to the prints designated Sa 3.

Before the painting and coating processes, surface of the steel must be cleansed from all kind of oil, rust and paint residue. In transformator tanks, sanding is the most efficient way to obtain a smooth and clean steel surface. During sanding process, sand is shooted to the surface of the steel with the help of high pressure air. Thus the surface is cleaned colloding the layer of the part, as much as desired. Grit size can be changed according to purpose. Since thin metal plates are used for transformator tanks, silica sand which has extra fine types, is used in mild volume sanding.

Sanding process is one of the steps which aims to protect the steel against oxidation. If steel is exposed to the atmosphere, a chemical reaction occurs between the steel and oxygen. Humidity and rain quicken this oxidation process. This issue is generally called as rusting and it weakens the steel day by day, at some point makes it unusable. In order to prevent oxidation of steel, the item must be coated with a protective material and/or must be painted. Thus, the item can be used safely for years.

Transformator tanks are going under approximately SA2.5 sanding process with the sanding cabinets, within Okuyan Metal Mühendislik San. and Tic. Co. Ltd. Also drying, airing and filtration processes which are necessary for sanding vessels are done in our company. 

Language

News

Since its been founded , Okuyan Metal Co. Ltd. has completed numerous projects successfully and now offering to you its experience, know-how and the understanding of ethical bussiness in manufacturing transformator tanks, corrugated walls and radiators. Our company makes customer oriented production in its facilities furnished with high quality, cutting edge equipments.

Our factory address:
Keresteciler Sanayi Sitesi 1.Cadde No:69-71 Saray
Kazan-ANKARA-TURKEY

Phone:
+90 544 626 2797

Fax:
+90 312 815 3108

Search

Okuyan Metal Co., Ltd.

Okuyan, put its signature to many succesfull projects, services with its experience, knowledge and commercial ethics, in the area of transformer tanks.

Download Catalouge

To download services and product catalouge of
Okuyan Metal Co., Ltd.
to your computer,
please click here.

Contact Us

Address: Keresteciler Sanayi Sitesi 1.Cadde No:69-71
Saray-Kazan-ANKARA
Phone: +90 544 626 2797
Fax: +90 312 815 3108
E-Mail: This email address is being protected from spambots. You need JavaScript enabled to view it.