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I think it is amazing that the range of available products for specialized applications has grown so exponentially over the last 10 years or so. I can remember when Loctite red and Loctite blue plus some cleaner covered it all! You can go to Permatex's web site and read about all of thier products. Quite an education. I really, really like the gel products... a bit more expensive but not so wasteful.
Blue is best for fasteners you can see, Red is for fasteners you can't see or that would give you an OMG near death experience (as opposed to an Ah $h!t) moment if it came loose.