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Finishing Aluminum Castings

Simplify the process of finishing aluminum castings by using high performance products from Vanchem

Finishing Aluminum Castings

Finishing Aluminum Castings

There are many steps involved in the process of finishing aluminum castings before the manufactured item is ready for painting. Using the example of a barbeque manufacturer, this article will briefly outline the steps of finishing aluminum castings from die-casting to painting.

After ingots are melted into a die-cast operation to produce parts such as barbeque bases and hoods, the part needs to be cleaned, phosphated, sealed, and rinsed before it can be painted. The pretreatment is tricky and you require a chemical supplier that really knows what they are doing. Vanchem is that supplier.

Two problems often occur immediately after the die-casting process. The mold release agent bonds to the surface of the aluminum, and the process of quenching (for cooling) leads to white oxide smut forming on the surface of the aluminum. For more on this topic, see our article on Degreaser Pretreatment of Aluminum or Phosphoric Acid on Aluminum.

Finishing aluminum castings begins with either a three or five step metal finishing process. To achieve a long lasting painted die-cast part, proper cleaning is central to finishing aluminum castings.

Vanchem’s VANCLEAN ALDC is the right product for this type of application.

VANCLEAN ALDC is a specially formulated cleaner-coater, which simultaneously cleans and coats when finishing aluminum castings is your goal. For high-end barbeques, it may be desirable to enhance the iron phosphate coating by running it through a straight iron phosphate like our FOSTEX 12F. To further enhance field performance, we recommend our RINSEAL 7 or RINSEAL 9 before final rinsing with DI or RO water (DI = deionized water, RO = reverse osmosis water).

Following the final rinsing stage, aluminum parts are dried under high heat. High heat is necessary to remove moisture including degassing entrapped air or carbon dioxide formed in the die-cast operation. This is known as degassing, which forces trapped gases within the die-cast metal to escape. If this step is not completed before the paint is applied, the paint may bubble during curing. At this point, the aluminum is ready to be painted to complete the finishing of aluminum castings.

Vanchem can assist you with all steps of finishing aluminum castings. For more information, contact our corporate headquarters in Burlington Ontario.