Here’s a lovely before-and-after shot of an Amco enameled aluminum juicer (bought at a local Williams Sonoma store) after only a few cycles in the dishwasher. Though this particular juicer came with no instructions whatsoever, the product description online clearly states “dishwasher safe.”
The manufacturer apparently missed the materials science class in which aluminum’s susceptibility to water corrosion in the presence of anything that dissolves the passivation layer was covered. I recall learning that aluminum parts could literally be destroyed in even a brief cleaning operation with detergents with high pH levels.
What happened to my juicer is also what guarantees that beach chair salesmen never lose their jobs, as salt water dissolves the passivation layer that ordinarily protects aluminum from its otherwise high rate of oxidation.
Aluminum also has high electronegativity. As the photo shows, there is clearly a ferrous hinge pin holding the two halves of the aluminum casting together, ensuring the kind of galvanic couple that guarantees that between citrus juices and high pH-level detergents, you are going to see all sorts of exotic reactions.
Geez, it’s a fricking battery!
While the baked enamel coating on this part was clearly intended to protect against exactly this type of thing and is harder and more wear resistant than paints, it clearly failed in its duties. The manufacturer probably chose it because it’s cheaper (it’s often a one-coat process) and more decorative than paint. Clearly those were the wrong performance trade-offs in this application!
Stainless steel or some sort of filled polymer seems like it would be a better choice, or clear instructions on NOT running the part through your dishwasher. Williams Sonoma doesn’t seem to carry the product any more and at least one retailer’s website notes that the product is currently out of stock — let’s hope that gets changed to permanently out of stock.
This post originally appeared on our sister publication Electronics Weekly’s website.