Originally Posted by twizted1
After seeing these pictures, the tank is a one piece design. The white & black that you are seeing are merely different layers of the tank which is very likely blow molded. The white is likely going to be virgin material with no color added, the black is likely virgin and reground material with color added. If the tank design/fab is similar to the tanks that I worked with at a fuel tank manufacturer will be multiple layers of material with a layer of less permeable material sandwiched between the inner and outer layers of material.
If the tank is of the construction I am describing, there is no separation between the white & black material shown in the picture.
*former engineer at a fuel tank manufacturer
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?