Pretreating Parts for Powder Coating: A Step by Step Guide

The devil is in the details. Did a powder coater coin this idiom? Unlikely – but they may as well have. Most customers don’t realize that when a metal part arrives at Kaser Blasting & Coatings, it undergoes an intense, multi-step pretreatment process before ever reaching the coating stage. Here’s how we pretreat steel and aluminum for powder coating.

Step one: a deep de-greasing.

Particularly dirty parts are treated with an alkaline cleaner, ensuring that all greases and oils are stripped away. Left unattended, old oils will bubble through the powder coating during the curing process, ultimately ruining the coating and compromising the durability.

Step two: a water rinse.

Once the part is clean, it undergoes a thorough water rinse, removing all traces of alkaline cleaner. This step requires meticulous attention to detail: if any cleaner is left on the part, the powder coating will not adhere properly. 

Step three: varies depending on the substrate.

If the part is steel, step three involves treatment with a proprietary phosphate solution, specially tailored to Lincoln water – this builds a conversion coating on the substrate.  A conversion coating prepares the substrate for powder application, and creates a barrier against future corrosion damage. Aluminum and stainless steel parts are treated with acid etchant, which prepares the surface for maximum coating adhesion.

Steps four and five: rinses.

We use purified water to rinse off any remaining chemicals. Then, if the part is aluminum or stainless steel, Kaser will apply a zirconium seal rinse. This conversion coat promotes adhesion and protects the aluminum or stainless steel against corrosion.

The finished product suffers if we shortchange any part of the process. On the other hand, if we were thorough with pretreatment, the powder coating will be smooth and durable, extending the life of the part and protecting it against damage.

Learn more about pretreating steel and aluminum for powder coating here.



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