One cause of leaking joints is fluid-gasket incompatibility. Some materials swell and others become brittle. Elasticity and recovery decline faster than expected and fluid finds a way out. Temperature and pressure accelerate this material breakdown and hasten premature failure. Testing gasket material for performance becomes a very important exercise.
Your Situation May Be Unique
The published information about which gasket materials to use and avoid with various fluids is always only a guide. The range of fluids to seal is virtually unlimited, and environmental factors vary. The only way to be completely sure any given gasket material will perform satisfactorily is to put it in the application.
Sample Testing
Gasket replacement is often costly, so while there’s no better test than to see how it performs in-service this isn’t a practical approach. The alternative is to expose samples of the gasket material or materials being considered to conditions like those in the application.
The simplest approach is to immerse pieces of the candidate materials in the fluid. Retain a control sample to allow quick comparisons to the initial material condition. Recover a test piece periodically to check for deterioration, or set up multiple samples for a range of test durations. Overall test duration should be as long as possible to replicate the in-service conditions.
If equipment is available, heat or cool the material to the temperature expected. Obviously, temperature cycling is hard to replicate, as are clamping loads. If the gasket material will be used outdoors, and particularly if it’s likely to see sunlight, place one or more samples outside.
Evaluation
Ideally, you would measure thickness to assess swelling, and look at compression under load and recovery. Often though, visual examination and feel are enough to gauge if the material is going to survive in the application.
Ask Hennig
Testing gasket material still doesn’t guarantee a long life, but it does reduce the probability of premature failure. Compared to the trouble of replacing a leaking gasket the effort is often worthwhile. Hennig Gasket is always happy to supply gasket material samples for evaluation. If you’d like to run your own tests, contact us today.
