I was thinking about using some TSP for degreasing the engine area of my chassis and prep the metal for POR-15 in this area. I read quite a bit about it on the web and it is described as a "wax and grease" remover as well as etching of painted surfaces in prep for new paint. Has anyone used TSP for anything related to degreasing and or painting their cars ?

Well, my experience is limited, but don't use it to degrease you engine block (final cleaning) before reassembly... Of course, nothing to do with body and paint...

My brother is a housepainter (and went through an extensive union training appreticeship), and he often uses TSP for cleaning, especially kitchens with cooking grease, because of those degreasing and etching properties...

I've used it for washing house walls also. Never heard it used on cars. Marine clean works great.

TSP (Tri-Sodium Phosphate) works great as a very-light grease cleaning/removal agent. It is cheap, mostly environmental friendly (there used to be phosphate issues), and takes very little in a gallon of water to do the job, and leaves hardly any residue. However, it probably will not work very well if you’re trying to de-grease a 35 year old engine that has never been cleaned up before. TSP is a great cleaning substance for around the home, but I wouldn’t wash my car with it.