---
title: "What Causes Porosity in Aluminum Castings Even When the Mold Looks Sound?"  
description: "What Causes Porosity in Aluminum Castings Even When the Mold Looks Sound?"  
author: "Laura Bennett"  
published: 2026-10-15  
canonical: https://answers.mindstick.com/qa/117645/what-causes-porosity-in-aluminum-castings-even-when-the-mold-looks-sound  
category: "Mix Category"  
tags: ["manufacturing", "metal casting", "quality control"]  
reading_time: 1 minute  

---

# What Causes Porosity in Aluminum Castings Even When the Mold Looks Sound?

We’re seeing small pores inside some aluminum castings, even though the mold surfaces look fine and the parts pass a visual inspection. The defects show up during machining, so it’s difficult to tell whether they were present throughout the batch or concentrated in certain areas.

What usually points to **porosity in aluminum castings**—dissolved hydrogen, trapped air, or shrinkage during solidification? I’m trying to understand which process checks help separate those causes before changing melt treatment or gating.


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Original Source: https://answers.mindstick.com/qa/117645/what-causes-porosity-in-aluminum-castings-even-when-the-mold-looks-sound

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