I’m not looking to blame users instead of products, but I do feel instructions are worth following. In that way we can better sort probable cause.
I agree about following the instructions and results. I think its why you hear the horror stories about WD40 and a few other things.
Before all this fancy stuff showed up, we used WD40 for decades, and never had any of the issues you constantly hear about it today.
As far as instructions and FL go, in the year or so I was using it, they seem to keep changing, as did the product itself, from bottle to bottle.
Initially, you were supposed to heat everything with a hairdryer or leave it out in the sun, by the time I stopped using it, that part had gone away, for the most part, and if I remember right, you only did that for long term storage.
Regardless, even following the directions to the "T", didnt stop the guns cleaned with it form becoming slow and sluggish in function, even if they sat for just a short while, but especially if they sat for a longer period.
I wonder when that rust test above was done in the timeline of their product. When I first started using it, it was thick and creamy, and almost seemed like it needed the heat to run. By the time I stopped using it, it was very watery and would run off things it had stuck to before.
It was towards the end too, when things were "watery", that I ran into some rust issues with it on my one S&W revolver. I cleaned the gun as normal with it, and when I grabbed it again a week later to go shooting, there was a fine coat of rust on the hammer, and a couple of places on the frame. That was a surprise. Made me wonder too, if that water change, was them just literally watering things down to make even more money off it.
My revolvers are what really caught my attention on the sluggishness thing, as the cylinders got "stiff", and wouldn't spin freely when the cylinder was open, and the cylinder "spun".
By the time the rust showed up, I was about done with it anyway, as it really wasnt working all that great as a cleaner (forget copper fouling), and anything that sat for a short while, seemed gummed up and sluggish when you went to use it.