Please post links iwhen asking questions in future, didn't you read the sticky?
I assume you're talking about the projects linked below:
1)
http://www.electronics-lab.com/projects/misc/014/index.html2)
http://www.electronics-lab.com/projects/misc/015/index.htmlNumber 2 won't work because a CMOS NAND gate can't output enough current to draw a relay.
Number 1 uses a 555 timer which can be configured to give a <50ms delay but it might not work with a relay because the contacts will take a finite time to open or close.