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Cleaning and Priming Before Powder Coating
Cleaning and priming surfaces are crucial to the successful outcome of the powder coating process.
Powder coating will bond better when the material it’s applied to is clean. To ensure surfaces are as prepped as possible, there are a number of steps that can be taken.
The pre-treatment of a part to be coated is the most important step in the entire coating process, regardless of the coating to be applied. If the component is not properly prepared, the applied coating WILL prematurely fail. If you have a metal that is oily and dirty, it will make the coating extremely hard to stick. So an important first step is to make sure you clean off the metal prior to coating.
Cleaning Before Powder Coating
In all of Microfinish’s coating operations there is a rigorous cleaning cycle. There are several steps we take to ensure it’s done right.
- Once you’ve prepped your metal for cleaning i.e., disassembling parts, It is important that greases, oils, dust and other contamination is removed in our heated alkaline spray wash.
- After the parts are washed, they are iron phosphated. The part will have an appearance, similar to the “bluing” on gun components. The iron phosphate increases the profile of the part by “roughing up” the surface with crystalline structures. This gives the powder coating a much better anchoring surface than applying powder directly onto an untreated substrate. Beside improving adhesion, iron phosphate improves the corrosion resistance of the part being powder coated.
- After, a seal can be applied over the phosphate surface, before the application of powder, to further increase the corrosion resistance of the coated part.
Priming & Surface Bonding
For 85-90% of the products that are powder coated, iron phosphate and a single coat powder is sufficient. In agricultural and earth moving equipment, which are exposed to harsh conditions, a primer powder coat is applied which is then top coated with a layer of powder. The primer is usually only partially cured, so that it is not over baked when being baked a second time to cure the top coat. It is believed, by leaving the prime to be fully cured with the top coat, there is some crosslinking between the layers of powder, thereby increasing the adhesion of the two applied coatings.
To ensure the best powder coating results, a clean metal is important. If you are looking for a manufacturer to help with your next powder coating project, give us a call today!
