Micro Cracks

    Many times we are asked if we can seal micro cracks in various substrates. The simple answer is "maybe", but it depends.

    To understand the answer, one first has to understand cracks and crack propagation. Cracks are generally the result of mechanical or thermo stresses that a part is either subjected to in operation, or in its manufacture. They are small and omni-directional. They can intersect and cause porosity like leakage in operation. More importantly, unlike porosity which has a rounded shape, cracks have a point and can expand in that pointed direction. In general, sealing the crack is not the problem, subsequent propagation is. Therefore, the maybe in sealing success is more related to the on-going pressure tightness of the part because of new crack formation.

    We have developed several different processes to deal with cracks. Most of these processes require extensive cleaning, enhanced impregnation cycles and careful thermo control during processing. The results in many instances have been very successful, with the leakage previously experienced due to the cracks eliminated for the entire duty cycle of the part.

    Technical services provided by Ramsey Network Systems, Inc.