How To Prepare a Part for Coating Application
How you prepare your object to be coated is one of the most critical parts to ensuring a proper high quality finish. The reason is that a proper finish provides a base for adhesion of your coating and a clean surface so that the coating is able to provide it’s intended qualities such as shine and protection. Preparation can be done primarily in two different ways, mechanically or chemically. We will cover the two methods and their uses in this article.
Mechanical preparation – Mechanically preparing a surface means using a physical abrasive to remove old coatings and to provide a roughened surface for paint adhesion. This can be achieved through use of a sandblasting outfit or sandpaper or other abrasive option. The benefit to this type of preparation is it provides a strong surface for base coat adhesion. It is also required sometimes by coating manufacturers or companies who will use the end product at times. Mechanical preparation can be faster as well than chemical preparation. Additionally, it allows for varying degree of coating removal. For example, you can remove all the paint of a surface, partial paint removal, or anything in between. Additionally, when done with proper equipment it can be a very safe way of part preparation.
Chemical preparation – Using an acid etch primer or similar chemical to prepare an item for coating can be an effective tool as well. The advantages to this are it can often clean and prepare a part with a single step, unlike mechanical preparation that will often require both mechanical and then a solvent wipe to remove excess metal dust. Additionally, when used in a dip tank with large parts or with small parts it can be the fastest way to prepare a part. The downside is the danger associated with harsh chemicals. This can also be less thorough preparation due to it not completely removing hard to remove paint.
Ultimately the type of preparation you use will be based on the requirements of your job. Some jobs will require mechanical and some chemical. The thing is if you experience poor paint adhesion, uneven finish appearance, or poor quality finish it is often best to look to how you are prepping. Is the part sandblasted thoroughly enough, is the part wiped with a cleaner prior to painting, has it been given enough time to dry if using a chemical preparation. These are all potential things to consider if your finish is not the quality you expect.