Originally Posted by JRWooden
Cool! An expert!
So is a crack that starts in the outer black layer of the tank likely to stop at the interface, or at least be slowed down, due perhaps to the layer of less permeable material between the inner and outer layer?
Is the less permeable material (in between) just a coating or does it have some real thickness to it that you could see if you examined the tank closely?
I've not been in the industry in 5 years now...but from the best of my memory, the layer thicknesses were dependent on the customer requirements and testing. A crack that started in any layer would eventually propagate through. The crack may "stop" for a time, but will eventually crack the next layer.
All my input is based on the one company I worked for in the fuel tank industry, BMW's tanks may be built/designed/molded in a different process or using different materials than I have experience with.