Hi Don -
 
Had a similar problem many years ago with some cast Al housings for an aerospace application.  After much testing and messing around with pressure, vacuum, He leak (using a mass spec) and other items, we arrived at a low pressure air bubble test, with the housing immersed in warm water.  We used this method for quite some time, until we discovered that the prevailing industry and governent specifications had methods for sealing castings to prevent porosity.  We commenced sealing and were able to phase out the casting level leak tests.  Sorry I no longer have the spec's involved at my fingertips, but I would expect that your casting house can be of assistance in this matter.  In our case, sealing turned out to be fully satisfactory, and far more economical in terms of both time and dollars.
 
Check the ASTM indexes - I would imagine that the subject is addressed there.
 
Regards - Kelly
 
 
-----Original Message-----
From: Steffen, Don E <[log in to unmask]>
To: [log in to unmask] <[log in to unmask]>
Date: Thursday, February 15, 2001 7:48 PM
Subject: [TN] Method of Leak Testing


Technetters

I am a Quality Engineer on a Safety Product that has a Leak Test requirement. We are using a die cast aluminum housing that has a porosity issue. I want to find out if there are any one in the TECH NET world that might have some experience in leak detection methods. Water is out of the picture. Because of the vertura effect, water can be sucked into a housing. I am presently using water for troubleshooting purposes, but everything that is applied to water is scrap. I have tried Helium gas but this is not always reliable and repeatable. Is there anyone out there that can help me out in this dilemma?



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