You provided some observations on the lack of control of the testing. I agree with you that the issues you point out will make providing absolute results impossible. e.g. Based on this test, this product will provide X hours of protection in a standardized salt spray test. (Not possible.)
However, I don't see any reason why the tests (at least the ones that took painst to avoid /contamination/cross contamination) would not provide accurate RELATIVE results. e.g. Based on this test, product X can be expected to outperform product Y in terms of corrosion protection.
You provided a list of "glaring problems" in the testing. A very thorough list.
Unfortunately unless there is a reasonable explanation for how those problems could be expected to actually CHANGE the test results then they amount to nothing more than nitpicking.
Please cease asking anymore of me.
Like the rabbit said to his friend who was being chased by a coyote: "Once you jump up, you gotta keep running!"
If you can reasonably explain how your list of "problems" will invalidate the test results then everyone who reads this thread will have learned something valuable about corrosion testing. Frankly, I'd like that since this is a topic that interests me considerably.
On the other hand, if you can't reasonably explain how your list of "problems" will invalidate the test results then everyone will have learned something about you.
Which gets us back to these three questions:
How would changing the specific steel alloy used in corrosion testing reasonably be expected to affect the RELATIVE results?
How would changing the environmental conditions (temperature/humidity) used in corrosion testing reasonably be expected to affect the RELATIVE results?
How would changing the specific test solution used in corrosion testing reasonably be expected to affect the RELATIVE results?