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Old 08-19-2020, 09:35 AM   #10
rotorwrench
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Join Date: Jun 2010
Location: San Antonio, Texas
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Default Re: I found a crack in an odd place while pressure testing

Real small tight grain inclusions in cast iron can be sealed with sodium silicate or water glass. Brazing works well due to the lower heat that is required to solder a small spot and then let it cool slowly so it doesn't crack on you. Pin it with cast iron pins or put an NPT plug in it if it's not too large. All are acceptable methods for repair of small cracks or pin holes. I've seen leaks where the core wire didn't meld in with the cast iron during the pour. It will leave a pin hole that would be easy to plug.

Last edited by rotorwrench; 08-19-2020 at 09:40 AM.
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