WD-40 and Heavy Oil-Based Cutting Fluids

Question: these products create coating problems and contaminate my wash and pre-treat stages.

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these products create coating problems and contaminate my wash and pre-treat stages. I need documentation on this problem.


Based on your email address, I will assume that you do powder coating at your location. Without exception, compounds like WD-40 and heavy oil-based cutting fluids will cause significant coating problems. You will experience serious surface defects such as cratering, fisheyes and complete loss of adhesion. Therefore, it is a requirement that these be removed prior to powder coating. It would be simple enough to demonstrate these defects to your management or parent company.

An effectively designed and well-maintained pretreatment system with the proper chemicals should do an adequate job removing those oils. The fact that you say that they are contaminating your system with these oils is what puzzles me. If the pretreatment system is doing an adequate job removing these soils, you should not be experiencing any serious paint defects (at least related to the pretreatment system). Over time, these lubricants will build up in the first stage of the pretreatment system (cleaning stage). If not designed into the wash system, you need to have effective fluid management in order to separate most of the oils from your washer and extend the life of the cleaning bath.

Skimmers and coalescing systems are both effective at doing this. They could be used together or separately. A skimmer is less expensive but will only remove the oil that has split out from the cleaner. This will require a quiet zone in order to give the fluid adequate residence time in order to effectively split from solution. The coalescer can be used with an agitated bath. It essentially provides artificial quite time for the cleaner and oil to split. The coalescer will draw fluid from the tank and then run it through various possible types of media that will accelerate the separation process. Either one or both of these methods will extend the life of the cleaning bath, although it will eventually need to be dumped and recharged.


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