light_volume help

hi, i have a spiker rifle, and im working on projectiles for it. so far they look...familiar, to most of you im sure. what id like help with is getting the light volume to fade away once the projectile has lodged into a surface. i want the light to fade, BEFORE the spike vanishes, so it will appear that the hot spike cooled down. ill post a screenie to show exactly what i mean. i want that glow to vanish approximatly 2 seconds before the spike does

http://i188.photobucket.com/albums/z...ikepicture.jpg

THINGS I AM NOT LOOKING FOR IN THIS THREAD

criticism on the spiker itself

flames

offtopic comments

YES I KNOW THE SPIKE LOOKS ALMOST EXACTLY LIKE CMT'S OLD ONE, I DIDNT RIP IT I MADE IT MYSELF, ANYONE WHO KNOWS THE HEK KNOWS EXACTLY HOW A LIGHT VOLUME SUCH AS THIS IS SET UP, SO PLEASE NO RIPPING ACCUSATIONS

thank you for your help