EagleEye,
You are right about one thing, this new compressor will surely not still be working 60 years from now. But since I'm now 69, I won't be either. The attraction to me was, of course, the price, but more than that is portability. The old Craftsman compressor weighs about 75 pounds and has no wheels. I could not justify the several hundred dollars that it would cost to acquire a USA manufactured compressor, so I did not hurt the American product because I would have just stuck with the old compressor.
Re: how long to pressurize: The key is the third sentence at the beginning of the page "As long as your sprayer has a pressure relief valve, you can pressurize it with a compressed air source and spray away for quite a while longer than you would from hand pumping. " The first clause is IMPORTANT. Do not pressurize any sprayer that does not have a pressure relief valve (PRV). Assuming you do have a sprayer with a PRV, simply add air until the PRV begins venting. You will then have a maximum charge. The charge will last longer if you fill the tank with liquid to 1/2 capacity. Always release all pressure before storing the sprayer. Always check hose connections to ensure the hose does not pop off while you are using the sprayer. All common sense, I suppose.
Sunbeam, We are talking about air and water based spray products such as herbicides, insecticides, and fungicides, not napalm.
I bet you would have a blast with a diet coke and mentos...Come to think of it, was this you????
http://www.youtube.com/watch?v=g4kBNBEJKD8&feature=related 
